Geology and paleontology of Canal Zone and adjoining parts of Panama


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Geology and paleontology of Canal Zone and adjoining parts of Panama
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Woodring, W. P ( Wendell Phillips ), 1891-1983
U.S. Govt. Print. Off. ( Washington )
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Geology and Paleontology Of Canal Zone and Adjoining Parts of Panama


Gift of the Panama Canal museum

Digitized by the Internet Archive
i n 2013

Geology and Paleontology Of Canal Lone and Adjoining Parts of Panama


GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-A .4 contribution to the history of the Panama' land bridge

UASch 3



FRED A. SEATON, Secretary


Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C.


Page Pacg
Abstract ------------------- ----------------- 1 Geology-Continued
Introduction --------------------------------------- 2 Igneous rocks ------------------------------Historical background ----------------------------2 Cretaceous(?) volcanic and intrusive rocks ----- 52
Purpose and scope of report ---------------------- 3 Tertiary volcanic and intrusive rocks .----------- 53
Orthography of geographic names ------------------ 4 Granular intrusive rocks ----------------- 53
Acknowledgments --------------------------------4 Dike rocks -----------------------------54
Annotated bibliography --------------------------5 Volcanic rocks and tuff --------- 5
Geology ------------------------------------------- 10 Chemical composition ----------------- 55
Stratigraphy ----------------------------------- 10 Age ----------------------------------- 56
Outline of stratigraphy ----------------------- 10 Structure ----------------------------------- 57
Cretaceous(?) system -------------------------13 Structural history --------------------------- 57
Eocene series ------------------------------- 13 Structural features ---------------------------58
Gatuncillo formation ---------------------13 Mineral resources ------------------------------- 58
Eocene or Oligocene series ------------------- 22 Metallic mineral deposits -------------------- 58
Marine member of Bohio(?) formation ----- 22 Nonmetallic mineral deposits ----------------- 59
Oligocene series ----------------------------- 24 Oil possibilities ------------------------------60
Bohio formation -------------------------24 Description of Tertiary mollusks -----------------------62
Caimito formation, exclusive of Madden Gastropods ------------------------------------ -62
basin and Pacific coastal area ----------- 28 Family Trochidae --------------------------- 62
Tuffaceous strata in Chorrera area -------- 31 Family Turbinidae -------------------------- 64
Bas Obispo formation and Las Cascadas Family Phasianellidae ------------------------65
agglomerate -------------------------- 31 Family Phasianellidae? -----------------------66
Oligocene and Miocene series ----------------- 32 Family Neritidae ----------------------------66
Caimito formation of Madden basin and Family Thiaridae? ---------------------------68
Pacific coastal area -------------------- 32 Family Littorinidae ------------------------- 6S
Miocene series ------------------------------ 34 Family Vitrinellidae ------------------------- 69
Culebra formation, including Emperador Family Rissoidae ----------------------------76
limestone member ---------------------34 Family Rissoinidae -------------------------- 77
Cucaracha formation -------------------- 39 Family Xenophoridae ------------------------77
Panam6. formation, including La Boca Family Hipponicidae -------------------------78
marine member and Pedro Miguel ag- Family Hipponicidae? ------------------------78
glomerate member ---------------------39 Family Crepidulidae -------------------------79
Gatun formation ------------------------ 42 Family Calyptraeidae ----------------------- 79
Pliocene series ------------------------------ 47 Family Naticidae --------------------------- 84
Chagres sandstone, including Toro lime- Family Turritellidae -------------------------97
stone member ------------------------ 47 Localities at which fossils were collected ----------------112
Pleistocene series ----------------------------50 References cited.----------------------------------- 131
Correlation of Tertiary formations in different Index ---------------------------------------------137
areas ------------------------------------ 50


[Plates 1, 2 in pocket, plates 3-23 follow p. 145]
PLATE 1. Geologic map of Canal Zone and adjoining parts of Panam ---------------------------------------In pocket
2. Geologic map of Gaillard Cut area, Canal Zone -------------------------------------------------- In pocket
3. Foraminiferal limestone from Gatuncillo formation of Madden basin, Panama.
4. Echinoid-bearing limestone from Gatuncillo formation of Madden basin, Panamii.
5. Boulder conglomerate of Bohio formation at Salud Point, Barro Colorado Island, Canal Zone.
6. Poorly sorted conglomerate of Bohio formation on Transisthmian Highway near Las Cumbres, just south of
continental divide, Panamd.
7. Alhajuela sandstone member of Caimito formation at north abutment of Madden Dam, Canal Zone.


PLATE 8. Emperador limstone member of Culebra formation on west bank of Panama Canal at canal station 1619, Canal
9. Coralliferous limestone at base of La Boca marine member of Panami formation on Rio Masambi 200 meters upstream from east bank of Panamia Canal, Canal Zone.
10. Strata in middle part of CaG:tun formation on east side of Catun Third Locks excavation, Canal Zone.
11. Toro limestone member of Chagres sandstone resting on marly siltstone in middle part of Gatun formation in
road cut 3 kilometers southwest of Gatun, Canal Zone.
12. Toro limestone member of Chagres sandstone in road cut 3 kilometers north-northwest of Gatun, Canal Zone.
13. (Chagres sandstone in road cut 3 kilometers south of Lagarto, Panam.
14-. Middle and late Eocene mollusks from Gatuncillo formation.
15. Late Eocene or early ()ligoene mollusks from marine member of Bohio(?) formation and late Oligocene mollusks
from middle member of (C'aimito formation in Gatun Lake area.
16. Early Miocene mollusks from Culebra formation and La Boca marine member of Panam. formation.
17. Middle and late Miocene mollusks from Gatun formation.
18. Middle and late Miocene mollusks from Gatun formation and early Pliocene mollusk from Chagres sandstone.
19, 20. Middle Miocene mollusks from Catlun formation.
21, 22. Middle and late Miocene mollusks from Catun formation.
23. Middle Miocene mollusks from Gatun formation.
FivuRE 1. Map of Panamnd showing principal areas of Tertiary marine sedimentary formations and area covered by plate 1_ 11 2. Unigulate mnetapodial from transition zone between Colebra and Cucaracha formations---------------------- 38
3:. Reconnaissance geologic map of Caribbean coastal part of Panamnt immediately west of (C'anal Zone- ------- 45 4. Correlation of Tertiary formations in different areas --------- 51




Most of the area covered by the present report lies in the Late Oligocene time also witnessed the deposition in the marine central Panama area of Tertiary marine sedimentary rocks, area of heterogenous strata overlying the Bohio formation. which extends obliquely across the trend of the isthmus. The These strata are almost entirely marine and are grouped as the central Panaml area contains a sequence of Tertiary deposits, Caimito formation. The Caimito overlaps the Bohio in the for the most part marine, ranging in age from middle Eocene northern part of Madden basin and apparently also northeast to early Pliocene. In the southwestern part of the Canal Zone of Gatun Lake, where it evidently rests directly on the basement. and farther west a thick sequence of volcanic rocks borders the The overlap indicates continuation of the minor movements marine area. In the Gaillard Cut area, along the Panama that affected the distribution of the Bohio formation. The
Canal, the marine and volcanic rocks interfinger. Caimito formation is made up chiefly of tuffaceous sandstone,
The oldest rocks, forming the basement on which the Tertiary tuffaceous siltstone, conglomerate, tuff, agglomerate, and formations rest, are more or less altered basaltic and andesitic limestone. In the Quebrancha syncline it includes the ecolavas. Altered tuffs containing microscopic marine fossils are nomically important Quebrancha limestone member, which is interbedded with the lavas. These basement rocks are of quarried for the manufacture of cement. The lower member
Cretaceous(?) age. Sometime during Late Cretaceous, Paleo- in the Gatun Lake area (or perhaps the entire formation) is cene, or early Eocene time they were strongly deformed and thought to grade southward into the Las Cascadas agglomerate perhaps at about the same time were intruded by dioritic and of the Gaillard Cut area. dacitic rocks. This is the strongest regional deformation in the Alternating marine and volcanic deposits were laid down in the known geologic history of this part of Panamd. Gaillard Cut area in early Miocene time. These deposits make
The middle and upper Eocene Gatuncillo formation rests with up, in ascending order, the Culebra formation, including the marked unconformity on the basement rocks. The Gatuncillo Emperador limestone member, the Cucaracha formation, and the is widely transgressive and is essentially uniform lithologically, Panamd formation, including the La Boca marine member and consisting principally of fine-grained detrital rocks. There is the Pedro Miguel agglomerate member. Though the Culebra no indication of nearby volcanism during middle and late formation contains much tuffaceous material, it consists of Eocene time. dark thin-bedded shale, mudstone, and siltstone; calcareous sandVolcanism reached a climax during Oligocene and early stone, and limestone-all laid down during a minor marine
Miocene time. The volcanic centers, which presumably are transgression. The Cucaracha formation consists almost entirely
now concealed by later volcanic rocks, evidently were located of nonmarine tuff, altered to bentonitic clay. Tuff and relain southern Panama not far west of the Canal Zone. A tongue tively fine grained agglomerate are the chief constituents of the of Oligocene(?) volcanic rocks, interpreted to have accumulated Panamd formation proper; silty mudstone, sandstone, limestone, at the periphery of a volcanic pile, extends eastward across the and tuff make up the La Boca marine member; coarse-grained canal in the northern part of the Gaillard Cut area. These agglomerate the Pedro Miguel agglomerate member. The La volcanic rocks, consisting of agglomerate, tuff, and thin ande- Boca marine member represents a reinvasion of the sea that sitic flows and flow breccias, constitute the Bas Obispo formation transgressed across the Cucaracha and Culebra formations onto and Las Cascadas agglomerate. They are considered of Oligo- the Bas Obispo formation. Two of these lower Miocene formacene(?) age because of their inferred relation to Oligocene tions, the Culebra and Cucaracha, are readily eroded. They deposits in the adjoining marine area. form topographic basins between hills of agglomerate and basalt,
The Oligocene deposits in the marine area are heterogenous and these topographic basins determined the course of the canal. and contain much volcanic debris. The earliest of these deposits The Panama formation is the youngest Tertiary formation in the are basaltic boulder conglomerate and basaltic graywacke Gaillard Cut area and in the Pacific coastal area east of the
forming the Bohio formation. This coarse debris, directly Canal Zone. overlying the fine-grained rocks of the Gatuncillo formation, Tuffaceous sandstone and limestone deposited in Madden indicates movements in the source areas. As a result of these basin during early Miocene time are grouped with the underlying movements the Bohio formation overlaps the Gatuncillo forma- strata of late Oligocene age in that area as the Caimito formation. tion in the Pacific coastal area east of the Canal Zone. The Though the lower Miocene part of the Caimito formation of Bas Obispo formation is thought to grade northward into the Madden basin is thought to include the equivalent of the lower Bohio. Though the Bohio represents for the most part an Miocene formations of the Gaillard Cut area, there is no satisextension of nonmarine deposits into the marine area, it includes factory faunal or lithologic correlation from one area to the other. marine deposits. Marine upper Eocene or lower Oligocene The lower Miocene formations of the Gaillard Cut area and the
strata in the western part of the Gatun Lake area are interpreted deposits in MIadden basin considered to be their equivalent as a marine member in the lower part of the Bohio(?); the basal represent the early half of the early Miocene, which corresponds part of the Bohio in the Quebrancha syncline includes lower to the late Oligocene of some paleontologists. The youngest Oligocene marine siltstone; and the upper part of the formation deposits in Madden basin (the Alhajuela sandstone member of on Barro Colorado Island and in the Pacific coastal area contains the Caimito formation), however, are younger than the disputed thin upper Oligocene marine deposits. Oligocene or Miocene. Madden basin is the only area where


late lower Miocene marine deposits have been found. They With one exception, accounts of the geology that
are alhnost exactly in the center of the present isthmus. were published before French operations started are
The ()ligocene and lower Miocene volcanic rocks include of historical interest only (Garella, 1845, 1849, pp. 519widespread rennants of basalt flows in the (Gaillard Cut and of historical interest only (Garella, 1845, 1849, pp. 519adjoining areas. The climax of volcanism during Oligocene and 524; Wagner, 1861; Maack, 1874, pp. 164-167; Wyse, early Mlioene time was a companied by marked intrusive Reclus, and Sosa, 1879, pp. 153-163; Boutan, 1880). activity. Stocks of quariz diorite, diorite, and dacitic and The exception is Boutan's account. His scientifically andesitic rocks, dikes of andesite, and dikes and irregular bodies and historically important paper, published in 1880, a of basalt represent that interval of intrusive activity and ar few years after the earliest description of the microscopic not known to be younger. few years after the earliest description of the microscopic
The Gatun formation was deposited during a middle and late petrology of American rocks, was based on a microMiocene marine transgression. The Gatun of the area covered scopic examination at the Ecole de Mines of rocks he by plate 1 is assigned to the middle Miocene. The upper part collected along the Panama Railroad just before French at lthe west end of the outcrop area is considered late Miocene. operations got under way. He also had a better idea The relations between the Gatun formation and the Caimito h
formation-the next older formation in the Gatun Lake and of the age of the sedimentary rock formations than his Caribbean coastal areas-are unknown. The apparent absence predecessors. Chaper's report (1890), written during of lower Miocene deposits in those areas indicates discontinuity, liquidation of the first French company, does not add and transgressive overlap of the Caimito is shown by relations much to Boutan's. at the east end of the outcrop area of the Catun, where it directly During the operations of the first French company overlies the basement rocks. At least minor movements (and o g tions of t French pan
perhaps regional deformation) took place before the Gatun was collections of fossils were sent to the French paleontolodeposited. How far inland beyond its present outcrop area the gist Henri Douvill&. His age assignments (Douvill6, (latun formation extended is not known. If it extended far 1891), published after liquidation of the first company, inland, presumably it extended through Madden basin. The placed the geology on a firmer footing. only tuffl in the Gatun formation is very fine-grained and The most important publication during the period evidently was (hderived from a distant source. of F
The (Chagres sandstone, including the Toro limestone member, of French operations was prepared by the French represents a minor early Pliocene transgression. The Chagres geologist Marcel Bertrand in collaboration with a crops out in a narrow belt along the Caribbean coast. The Toro Swiss engineer who had worked on the canal, Philippe limestone member consists of thin basal calcareous strata de- Ziircher (Bertrand and Ziircher, 1899). It was based posited in shallow water. These shallow-water deposits suggest on the work lone by the French companies and on a that the formation did not extend much beyond its present inland by D l (1898 The
border. The Chagres contains little tuffaceous material. new set of age assignments by Douvill4 (1898). The
The imo(deratelv strong deformation of the pre-Gatun Tertiary account by Bertrand and Ziircher emphasized the folformations is of regional extent, the results of the second regional lowing major features of the geology along the canal: d(leformation, but is not well dated. It may have taken place the pyroclastic rocks and associated lavas southeast of (during early Miocene time or during Pliocene time after deposi- the big bend in Rio Chagres at the present site of tion of the C(hagres sandstone. The Gatun formation and Chagres sandstone are only mildly deformed, but mild deforma- Gamnboa are the oldest rocks; the strata overlying them tion in the Caribbean coastal area may have taken place at, the are in general progressively younger toward both the same time as stronger deformniation elsewhere. Caribbean Sea and the Pacific Ocean; the fossiliferous
Pleistocene deposits, characterized by much black organic strata are of Oligocene and Miocene age. The volmaterial, are found in valleys that were cut in the Chagres standstone and older formaions and later filled (during sub- ct rocks re now thought to be of the same age as emergence. Near the coast the Pleistocene strata include fossilif- the oldest sedimentary formations along the shores of erouis marine deposits. Gatun Lake. Otherwise Bertrand and Zilrcher's conSeventy-eight species and subspecies of Tertiary mollusks, clusions have been confirmed by later investigations representing 15 families of gastropods, are described and 13 and are accepted at the present time. others are recorded. Fifty of the 91 forms are from the Gatun In the meantime R. T. ill visited Panam in 1895, formation. These 91 forms are estimated to represent about a
seventh of the total available molluscan fauna in the marine before the second French company resumed operations. Tertiary formations. He evidently did not have access to most of the subINTRODUCTION surface records and there is no indication that he was
aware of Douvill4's 1891 note. His report (1898) was
HISTORICAL BACKGROUND supported by paleontologic work by Dall. Hill thought
Marked advances in knowledge of the geology of the the oldest strata, probably pre-Tertiary, to be on the
present Canal Zone coincide with three periods of active Pacific coast. Through some misfortune, one of his investigations bearing on construction of the canal or collections of fossils was mislabelled before it reached
on proposed changes affecting it: French operations Dall's hands. As a result of the mislabelling, Dall
(1881-89 and 1895-99), American construction (1905- referred part of the Gatun formation to the Eocene,
13), and Third Locks and Sea-level Conversion Route an error that affected American geologic literature for
studies (1938-48). many years.


Soon after American operations were started, Ernest as the Culebra formation, also are younger than that Howe was employed by the Isthmian Canal Commission formation. to study the geology. Though he was in the Canal
n PURPOSE] AND SCOPE OF R EPORT Zone only five months during 1906 and 1907, his
reports clearly set forth the essential features and went The National Museum's collection of fossil nmollusks a long way toward systematizing the stratigraphic from the Canal Zone represent a collecting span of a nomenclature (Howe, 1907, 1907a, 1908). Appoint- century. Not many collections, however, were received
ment of D. F. 'MacDonald, formerly of the U. S. prior to 1911, when the fossils collected by MacDionald
Geological Survey, as resident geologist during the last began to arrive. It was expected that the mollusks two years of the construction period (1911-13) led to would be studied by W. 11. l)all, the (lean of American further advances and to the gathering of much infor- Tertiary invertehr!ite Daleontologists. For the most mation (MacDonald, 1913, 1913a, 1915, 1919). Only part he got no further than generic identification of the first of the four publications by MacDonald just MacDonald's early collections. Therefore the mnolcited is generally cited on the following pages in the lusks-the most abLindant fossils then availablediscussion of the stratigraphy. The others contain were omitted when Bulletin 103 was assembled. A practically identical descriptions, aside from new names. considerable number of mollusks fron the richly fosMany of the fossils described in the present report were siliferous Gatun formation, collected while the canal collected by MacDonald or by MacDonald and was being constrLcted, were described by Toula (1909, Vaughan, when Vaughan collaborated with him in the 1911) and by Brown and Pilsbry (1911, 1913) before latter part of 1911. The stratigraphy, as worked out the publication of Bulletin 103. Other Gatun species by MacDonald and Vaughan, was described in Bulletin have been recorded in scattered publications, and also 103 of the U. S. National Museum (Vaughan, 1919). a few from other formations (Culebra formation and Z n f -t sE m p r a d l m e s o n e m e re b e r o r o l i m e s t o n e Though Bulletin 103 was issued in 1919, many of its its Emperador limestone e o l n
parts were published separately in 1918, and Jackson's member of Chagres sandstone). Nevertheless the part on the echinoids was issued separately in 1917 National Museum collections represent much valuable and again in 1918. In the preparation of Bulletin 103 information, which is not in useable form until the Vaughan enlisted the services of a group of paleontolo- fossils are adequately studied. The present report is gists, who described practically all the Canal Zone designed to meet that nee(d. fossils then available in the National Museum collec- The collections obtained before and during contions, except the mollusks. Not all the fossils described struction of the canal are especially valuable, for very in Bulletin 103 are mentioned in the summaries on the few of them can be duplicated. Some of them, parfollowing pages. Calcareous algae (X. A. Howe, 1918), ticularly in Gaillard Cut, represent excavated prisms land plants (Berry, 1918), Bryozoa (Cau and Bassler, of rock: many other localities are now submerged; 1918), decapod crustaceans (Rathbun, 1918), and still others are inaccessible through the rapid disbarnacles (Pilsbry, 1918) are omitted, integration of rock and the rapid growth of at thick
The third period of marked advances resulted from cover of vegetation.
investigations, including the study of some 2,000 cores, To take advantage of the store of information of the Geological Section of the Special Engineering gathered by the Geological Section of the Special Division of the Panama Canal, carried out under the Engineering Division, field work in the Canal Zone was direction of T. F. Thompson. The surface and sub- undertaken during the dry season early in 1947. By surface studies undertaken by this staff of geologists that time it was evident that work in the fairly cornwere for the most part directly related to the Third plete succession of lower and middle Tertiary marine Locks and Sea-level Conversion Route projects. The formations in Panami east of the Canal Zone was published reports prepared by the Geological Section needed to interpret the less complete partly marine include sunmiaries of the geology and more detailed succession of the same age in the Zone. Further field work was carried out early in 1949 and early in 1954.
descriptions of particular areas (Thompson, 1943, The work in 1954 was limited to Barro Colorado Island 1943a, 1944, 1947, 1947a). The oldest rocks, older and nearby parts of the Gatun Lake area. The than any along the canal, were found to consist of a geology of Barro Colorado is to be described in a basement of unknown age overlain by deposits of separate publication.
Eocene age. Agglomerate along the southeastern part The field work was designed as a stratigraphic and
of the canal, formerly correlated with agglomerate paleontologic project-not as a mapping project, which underlying the Culebra formation, overlies the Culebra. would have been very time-consuming. Some kind Marine deposits in the same region formerly identified of map, however, was needed to show the localities


at which fossils were collected. A decision was reached are recorded. These 91 forms are estimated to repreto compile a geologic map, based on the material in sent about a seventh of the total available molluscan the publications and files of the Geological Section of fauna to be described. Fifty of the 91 are from the the Special Engineering Division, supplemented by Gatun formation, anll indication of the size of the Gatun scattered personal observations. The resulting map fauna. oin the scale of 1:75,000, issued as a separate publication Fuller discussion of the age and correlation of the in 1955, is reproduced with minor alterations as plate formations is planned for the final part of the report. 1 of the present report. The quality of the map is That part also is to contain a discussion of the broader very uneven. Parts of it show the geology in con- aspects of the succession of faunas, including their bearsiderable detail; other parts are greatly generalized ing on the history of the PanamA land bridge and the and represent rapid reconnaissance. Despite its de- light they shed on paleoecology. fects, however, it shows the geologic setting of the
Canal Zone and adjoining parts of PanamA. The only ORTHOGRAPHY OF GEOGRAPHIC NAMES
comparable map was published by MacDonald (1915, Spanish orthography, including accent marks, is used
pl. 4; 1919, pl. 153) on a scale of about 1:260,000. The for geographic names in PanamA. In the Canal Zone, base used for the 1955 map does not show the recent however, many names of Spanish origin are anglicized suburban expansion of the city of PananmA. and for such names accent marks are omitted. The
At first the present report was planned to consist of a major streams cross the boundary, and therefore "rio" discussion of the stratigraphy, summaries of the occur- or "quebrada" is used for all the streams that are rence of fossils other than mollusks, and description of named, regardless of location. The plan just outlined the Tertiary mollusks. While the work was in progress, results in "PanamA" for the name of the country, the an incomplete carbon copy of a manuscript by Mac- capital city, and a geologic formation, but "Panama Donald on the geology of PanamA was found among Railroad" and "Panama Canal" for two features in
Dali's effects at the U. S. National Museum. This the Canal Zone. report, prepared soon after MacDonald's tour of duty ACKNOWLEDGMENTS
as resident geologist in the Canal Zone, was mentioned
by MacDonald (1913, p. 579) and Vaughan (1919, p. v). Brig. General J. H. Stratton, (retired, then Col.), It was not finished because Dall's work on the fossils Supervising Engineer in charge of the Special Engineerwas not completed. One of MacDonald's duties as ing Division, and T. F. Thompson, Chief of the Georesident geologist was to recommend rock for use as logical Section of the Division, placed every facility at concrete aggregate, as armoring for breakwaters and my disposal during the field work in 1947, and Mr. earth dams, and for other construction purposes. In Thompson again in 1949, when the Division had praccarrying out this assignment he examined outcrops of tically completed its work and its staff was greatly igneous rocks, studied thin sections of them, and ar- reduced. Mr. Thompson has a wide familiarity with ranged for chemical analyses of some of the rocks to be the geology of the Canal Zone and PananiA, which he made in the chemical laboratory of the U. S. Geological freely shared, and he guided me to many localities where Survey. His description of the rocks, which is more fossils are available. Other geologists of the Geological complete than his published notes, and the chemical Section were very helpful. Special acknowledgment analyses are included in his manuscript. They have should be made to S. K. Bartholomew, L. H. Henderbeen incorporated inii the present report, although the son, S. M. Jones, J. M. Matthews, T. G. Moran, J. R. analyses have already been puliblislihed. Schultz, R. II. Stewart, J. A. Tavelli, and L. C. Woolfe.
Though the present report includes more than stra- The general geologic map (pl. 1) is based for the most tigraiphy and paleontology, the title-chosen for brev- part on material gathered by geologists of the Geoity-is too comprehensive. Many aspects of the geology logical Section: principally a published map of the are omitted or are only briefly considered. This report Gatlun Lake area by S. M. Jones (1950, pl. 2); a map is, in fact, a progress report so far as the geology is of the Quebrancha syncline by T. F. Thompson, a concerned. Much of the area covered by plate 1 has not small part of which was published (Thompson, 1944); yet been studied and it may be a long time before the a map of an area east of Gamboa, between Rio Chagres entire region is adequately studied. and Madden Highway, by L. C. Woolfe; strip maps
The syst enalitic paleontology deals with the mollusks along the proposed sea-level canal (Thompson, 1947a, in about 260 collections from all the fossiliferous Terti- figs. 29-32); strip maps of the Chorerra route by J. R. ary formations, which range in age from middle and late Schultz. Mr. Thompson and Mr. Stewart offered Eocenle to early Pliocene. In chapter A, 78 species and valuable suggestions for filling in gaps. I, however, subspecies of gastropods are describedd and 13 others must assume responsibility for the map's shortcomings,


which will become apparent as additional work is done. the canal-notably on the canal slides-despite menG. E. Lewis, of the U. S. Geological Survey, and J. G. tion or discussion of geologic features. The three exMarks, of Creole Petroleum Corporation, assisted in ceptions are 'MacI)onald's U. S. Bureau of Mines
preparation of the Spanish explanation. The sea- Bulletin 86, issued in 1915, the National Academy of
level canal strip maps already mentioned were used for Sciences 1924 report on slides, and MacDonald's
the more detailed map of the Gaillard Cut area (pl. 2). 1947 posthumous publication on the same subject. The field photographs, from the files of the Special No attemI)t has been made to glean incidental geologic Engineering Division, are available through the kind- observations from early literature. A great lumber
ness of Mr. Thompson. of travelers crossed the isthmus during the California
Large faunas of smaller Foraminifera from the Gatun- gold rush, first by boat up Rio Chagres to Las Cruces cillo and Bohio formations, collected in 1947 and 1949, (a short distance above the )resent site of Gamboa) were identified by H. H. Renz and P. J. Bermidez, and thence by muleback, and later by the Panama
both of Caracas, Venezuela. Larger Foraminifera Railroad, which was completed in 1855. Some of the
collected at the same time were identified by W. S. travelers who wrote about their journey in books or
Cole, of Cornell University and the U. S. Geological nongeologic periodicals may have recorded observaSurvey (Cole, 1952 (1953)); corals by J. W. Wells, of tions on the geology.
Cornell University and the U. S. Geological Survey; 1845. Garella, Napolcon, Projet (t'un canal de jonction de
echinoids by C. W. Cooke, of the U. S Geological l'Oc6an Pacifique et de 1'Ocean Atlantique A, travers
Survey (Cooke, 1948). M. N. Bramlette, of the l'isthme de Panama, 233 p., maps, profiles, Paris.
Scripps Institution of Oceanography and the U.S. Ch'lper 4 (p. 35-46), "AperS. geologique sur la
constitution des terrains de l'isthme", is generalized
Geological Survey, furnished notes on smaller Forami- and of little interest. The 1:200,000 hachured
nifera found in the Caimito and Culebra formations topographic map, prepared in 1844, is an important
and in the La Boca marine member of the Panamdi for- historical document.
mation. R. A. Stirton, of the University of California, 1849. Garella, Napol6on, Project of a canal to connect the kindly furnished drawings of a mammal bone and coin- Atlantic and Pacific oceans across the Isthmus of
L, Panama: U. S. 30th Cong., 2nd sess., House Rept.
ments concerning that interesting fossil. Samples of
145, p. 506-590, maps, profiles.
lava and tuff from the basement complex were examined Translation of preceding publication.
by W. S. Burbank, of the U. S. Geological Survey, who 1853. Moore, J. C., Notes on the fossil Mollusca and fish from
also kindly read the part of the report dealing with the San Domingo: Geol. Soc. London Quart. Jour.,
igneous rocks. v. 9, p. 129-132.
Extensive collections of mollusks from the Gatun A note at the end of this paper (p. 132) is the first
record in a scientific journal of the discovery of
formation, deposited at Stanford University by Mr. M1iocene fossils in the present Canal Zone. The
Thompson, were generously loaned by Miss A. Myra fossils were found "about 2/12 niles from the shores
Keen. For permission to examine types and other of Navy Bay [Limon Bay] * in a cutting of the
specimens I am indebted to H. A. Pilsbry, A. A. Panama Railway" [near Mindi].
Olsson and Miss Anne Harbison, of the Academy of 1855. Deck, Isiah, Notes on the geological features of the
Panama Railroad: Mining Mag., v. 4, p. 240-215,
Natural Sciences of Philadelphia; W. S. Cole, of Cornell New York.
University; the late G. D. Harris, of the Paleontological Fossils were observed at Monkey Hill [Mount
Research Institution; J. W. Durham, of the University Hope] but not at Gatun.
of California; and L. G. Hertlein, of the California 1855. Conrad, T. A., Report on the fossil shells collected in
of Sciences. For much advice I am indebted California by Win. P. Blake, geologist of the expeAcademy edition under the command of Lieutenant R. S. to H. A. Rehder, of the U. S. National Museum, and Williamson, United States Topographical Engineers;
R. T. Abbott, formerly of that institution, where this appendix to the preliminary geological report of
work was carried out. William P. Blake: U. S. Pacific R. R. Expl., U. S.
33rd Cong., 1st sess., House Ex. Doe. 129, p. 5-20.
ANNOTATED BIBLIOGRAPHY Includes three species of mollusks collected by
The following briefly annotated bibliography lists Blake. The type of one species (Gratelipia? mactropsis) is in the National Museum.
publications on the geology and paleontology of the 1857. Blake, W. P., Geological report [Williamson's reconnaisCanal Zone and adjoining parts of Panama'. It includes sance in California]: U. S. Pacific R. R. Expl., v. 5,
publications containing information on those subjects, pt. 2, 370 p., 11 pls., maps, sections.
though the publications are primarily devoted to other Observations on trip across Panaimi are recorded
thoug h t(p. 1-2). A few fossils were collected "at Gatun,
areas. With three exceptions, it does not include or Monkey Hill?." The species indicate they were
publications on engineering aspects of construction of collected at Gatun.
413788-57- 2


1857. Conrad, T. A., Descriptions of the fossil shells [William- Includes mollusks from Vamos Vamos, Gatun,
son's reconnaissance in California]: Idemin, app., and Monkey Hill [Mount Hope].
art. 2, p. 317-329, pls. 2-9. 1891. Douvill6, Henri, Sur l'Age des couches traverses par le
Conrad's 1855 descriptions are repeated and poor canal de Panama: Acad. Sci. Paris Compte Rendu,
illustrations are added. t. 112, p. 497-499.
1857. Conrad, T. A., Description of the Tertiary fossils collected First modern age assignments. The fossiliferous
on the survey [Williamson's survey in California and strata are assigned to Oligocene and Miocene.
Oregon]: Idem, v. 6, pt. 2, p. 69-73, pls. 2-5. 1896. Guppy, R. J. L., and Dall, W. H., Descriptions of
Includes five species of mollusks collected by Tertiary fossils from the Antillean region: U. S.
Newberry at Gatun. Natl. Mus. Proc., v. 19, p. 303-331, pls. 27-30.
1861. Wagner, Moritz, Beitrige zu einer physisch-geographis- Includes two species of mollusks from Gatun and
chen Skizze des Isthmus von Panama: Petermanns Monkey Hill [Mount Hope].
Mitt., Erginzungsheft 5, 25 p., map. 1898. Hill, R. T., The geological history of the Isthmus of
Geologic observations are incidental and unim- Panama and portions of Costa Rica: Mus. Comp.
portant. Reddish conglomerate and fragmental Zool. Harvard College Bull., v. 28, p. 151-285,
rocks at city of PanamA are assigned to Permian. 19 pls., 24 figs.
1874. Maack, G. A., Report on the geology and natural history Geology of Panama Railroad and French canal.
of the isthmuses of Choco, of Darien, and of Panama, 1898. Douvill6, Henri, Sur l'Age des couches traversees par in Selfridge, T. O., Reports of explorations and le canal de Panama: Soc. Gaol. France Bull., 3me
surveys to ascertain the practicability of a ship-canal ser., t. 26, p. 587-600.
between the Atlantic and Pacific Oceans by the way Some of Douvill6's 1891 age assignments are
of the Isthmus of Darien, p. 155-175, Washington. changed; others are reinforced by additional data.
Geologic observations along Panama Railroad 1899. Bertrand, Marcel, and Ztircher, Philippe, Etude g~olo(p. 164-167) are inconsequential. Maack, like gique sur l'isthme de Panama: Compagnie Nouvelle
Wagner, suggested a Permian age for red conglom- du Canal de Panama, Rapport de la Commission,
crate at Panami. app. 1, p. 83-106, map, structure sections, Paris.
1879. Wyse, L. N. B., Reclus, Armand, and Sosa, P., Rapports Most satisfactory of earlier accounts of geology of
sur les 6tudes de la commission internationale canal route. The map (scale 1:100,000), which has
d'exploration de l'isthme am6ricain, 294 p., 2 maps, 10-meter (or several tens of meters) contours along
Paris. route of canal and up Rio Chagres to Alhajuela, is
Account of geology along route of proposed canal, the last and the best of the French maps.
like earlier accounts, is of historical interest only. 1899. Bouvier, E. L., Calappa zurcheri, crabe nouveau des List of rocks collected (p. 279-280) was prepared by terrains miocknes de Panama: Mus. Hist. Nat.
Daubrde. Paris Bull., t. 5, p. 189-192, 1 fig.
1880. Boutan, E., Note sur la constitution g6ologique de Locality where this fossil was found is not specified.
l'isthme de Panama: Annales de Mines, 7th ser., 1901. Hershey, O. H., The geology of the central portion of the t. 18, p. 5-58, 2 pls. (map and profiles). Isthmus of Panama: Calif. Univ., Dept. Geol.,
Interesting account of geology along route of Bull., v. 2, p. 231-267, map.
proposed canal, based on microscopic examination, Panaml formation at and near PanamA is briefly
at Ecole des Mines, of rocks collected along Panama mentioned (p. 245-246). Hershey's age assignments
Railroad. are much too old.
1881. Gabb, W. M., Descriptions of Caribbean Miocene fossils: 1904. Cushman, J. A., Pleistocene foraminifera from Panama:
Acad. Nat. Sci. Philadelphia Jour., 2d ser., v. 8, Am. Geologist, v. 33, p. 265-266.
p. 337-348, pls. 44, 45. List of 14 species from a locality near Mindi.
Includes eight species of mollusks collected by 1904. Lemoine, P., and Douvill4, R., Sur le genre Lepidocyclina
Newberry at Gatun. Gimbel: Soc. G6ol. France Man. 32 (t. 12), p. 1-42,
1886. Wyse, L. N. B., Le canal de Panama, 399 pp., maps, pls. 1-3.
woodcuts Paris. Includes Lepidocyclina chaperi and L. canellei,
w scustsrio both named for engineers of first French company.
Discussion of geology (pp. 12-20) is drawn from 1907. Howe, Ernest, Report on the geology of the Canal Zone:
earlier accounts. Fossils at scattered localities are
Isthmian Canal Comm., Ann. Rept., 1907, app. E,
mentioned. Shaded relief map of canal route is on p10- ,l 1 .
scale of 1: 100,000. 108-138, p. 147.
Principal features of Canal Zone geology.
1890. [Chaper, -- -], Description g6ologique des terrains 1907. Howe, Ernest, Isthmian geology and the Panama Canal:
traverses par le canal: Commission d'6tudes in- Econ. Geology, v. 2, p. 639-658, pl. 8.
stitude par le liquidateur de la compagnie universelle, Economic aspects of geology are emphasized.
Rapport 6, 30 p., Paris. 1908. Howe, Ernest, The geology of the Isthmus of Panama:
According to Douvill6 (1898, p. 589, footnote), Am. Jour. Sci., 4th ser., v. 26, p. 212-237.
Chaper, an engineer of the first French company, Stratigraphy and paleontology are emphasized.
wrote this account. It does not add much to 1909. Toula, Franz, Eine jungtertidre Fauna von Gatun am
Boutan's. Black fossiliferous limestone at Vamos Panama-Kanal: K. k. Geol. Reichsanstalt Jahrb.,
Vamos, however, is mentioned. Band 59, p. 673-760, pls. 25-28, 15 figs.
1890- Dall, W. H., Contributions to the Tertiary fauna of Mollusks, otoliths, and a few other fossils from
1903. Florida: Wagner Free Inst. Sci. Trans., v. 3, 6 pts., Gatun formation, Tiiostly from Gatun Locks site
1,654 p., 60 pls. and spillway of Gatun Danm.


1911. Brown, A. P., and Pilsbry, H. A., Fauna of the Gatun 1913. Cossmann, M., Etude comparative de fossils mioe6niques
formation, Isthmus of Panama: Acad. Nat. Sci. recueillis h la Martinique et A l'isthmne de Panama:
Phila. Proc., v. 63, p. 336-373, pls. 22-29. Jour. Conchyliologie, t. 61, pp. 1-64, pls. 1-5.
Mollusks from Gatun Locks site, one of which also Includes mollusks from Gatun formation at Mindi
occurs at Monkey Hill [Mount Hope]. and Monkey Hill [Mount IHope].
1911. Toula, Franz, Die jungtertidre Fauna von Gatun am 1915. Douvill6, Henri, Les couches A orbitoides de l'isthme de
Panama-Kanal; 2. Teil: K. k. Geol. Reichsanstalt Panama: Soc. G6ol. France Compte Rendu Som.,
Jahrb., Band 61, p. 487-530, pls. 30, 31. 1915, no. 16, p. 129-131.
Mollusks and a few coral, echinoid, and crab Oligocene age of limestone on upper Chagres
remains. [Gatuncillo formation] is reiterated, despite presence
1912. Dall, W. H., New species of fossil shells from Panama of a discocyclinid. Strata at Pefia Blanca [Caimito
and Costa Rica: Smithsonian Misc. Coll., v. 59, formation] and Pedro Miguel [probably Culebra
no. 2, 10 p., March, 1912. formation] are considered to be of Aquitanian age.
Includes 11 species of Pleistocene mollusks 1915. MacDonald, D. F., Some engineering problems of the
collected near Mount Hope and 1 species and variety Panama Canal in their relation to geology and topogcollected at Toro Point [Toro limestone member of raphy: U. S. Bur. Mines Bull. 86, 88 p., 29 pls.,
Chagres sandstone]. 9 figs.
1912. de Boury, E., in Cossmann, M., Essais de paldoconch- The name "Toro limestone" is proposed. Deologie compare t. 9, 215 p., 10 pls., August, 1912. scription of some formations is more detailed than in
The fossil from Toro Point described by Dall five MacDonald's earlier publications.
months earlier as Epitonium (Sthenorytis) toroense 1917. Sheldon, P. G., Atlantic slope Areas: Palacontographica
is described by de Boury as Stenorhytis chaperi (p. Americana, v. 1, no. 1, p. 1-101, pIs. 1-16.
177). A new name, Area balboai (p. 69), is proposed for
1913. de Boury, E., Catalogue raisonn6 de la collection de a species from Culebra formation.
Scalaria vivants et fossiles du Museum de Paris: 1917. Jackson, R. T., Fossil echini of the Panama Canal Zone Mus. Hist. Nat. Paris Nouv. Arch., 5me ser., t. 4, and Costa Rica: U. S. Natl. Mus. Proc., v. 53, p.
p. 209-266, pls. 12-16. 489-501, pls. 62-68, 4 figs.
Includes another description of Stenorhytis chaperi Echinoids from Emperador limestone [member of
(p. 252). Culebra formation] and Gatun formation.
1913. Brown, A. P., and Pilsbry, H. A., Fauna of the Gatun 1918. Howe, M. A., On some fossil and Recent Lithothamnieae
formation, Isthmus of Panama; pt. 2: Acad. Nat. of the Panama Canal Zone: U. S. Natl. Mus. Bull.
Sci. Phila. Proc., v. 64, p. 500-519, pls. 22-26, 5 figs., 103, p. 1-13, pls. 1-11.
1912 (1913). Calcareous algae from Caimito formation [misMollusks from Gatun formation, from "the Pecten identified as Culebra formation and Emperador
bed at tower N, Las Cascadas" [Emperador lime- limestone member] and Pleistocene deposits. Reisstone member of Cuelbra formation], and mollusks sued in complete volume, 1919.
and a crab from "the lignitic layers near tower N, 1918. Berry, E. W., The fossil higher plants from the Canal
Las Cascadas" [Culebra formation proper]. Zone: Idem, p. 15-44, pls. 12-18.
1913. Brown, A. P., and Pilsbry, H. A., Two collections of Plants from Bohio, Culebra, Cucaracha, and
Pleistocene fossils from the Isthmus of Panama: Gatun formations. Reissued in complete volume,
Idem, v. 65, p. 493-500, 3 figs. 1919.
Numerous Pleistocene mollusks and a barnacle
collected near Mount Hope and at north end of 1918. Cushman, J. A., The smaller fossil Foraminifera of the
collected near Mount Hope and at north end ofPamaCnlZe:Irp.4-7ps.13.
Gatun Locks are listed, and 6 species and subspecies Panama Canal Zone: Idem, p. 45-87, pls. 19-33.
of mollusks are described. Foraminifera from Caimito [misidentified as
of mlluks ae dscried.Culebra] and Culebra formations, Emperador lime1913. MacDonald, D. F., Geology of the Isthmus: Canal Culebra] and Culebra formation, Emperador limestone member of Culebra formation, La Boco marine
Record, v. 6, no. 27, p. 213-215, Feb. 26, 1913. member of Panama formation [misidentified as
member of PanamA formation [misidentified as
A preliminary account. Stratigraphic nomenA preliminary account. Stratigraphic nomen- Culebra formation], Gatun formation, and Pleistoclature is same as in next item, but it would be in- e ra Rio] n omto 19
appropriate to cite a weekly periodical of limited cene strata. Reissued in complete volume, 1919.
distribution for new stratigraphic names. 1918. Cushman, J. A., The larger fossil Foraminifera of the
1913. MacDonald, D. F., Isthmian Geology: Isthmian Canal Panama Canal Zone: Idem, p. 89-102, pls. 34-45.
Comm., Ann. Rept., 1913, app. S, p. 564-582, pls. Foraminifera from Caimito formation [misidenti65-77. fled as Culebra formation and Emperador limestone
With exception of names published later, this pub- member], Culebra formation and Emperador limelication is cited in present report for MacDonald's stone member, and La Boca marine member of
stratigraphic geology. Published in latter part of Panama formation [misidentified as Culebra forma1913; transmittal of volume is dated Sept. 15. tion]. Reissued in complete volume, 1919.
1913. MacDonald, D. F., Geologic section of the Panama 1918. Jackson, R. T., Fossil echini of the Panama Canal Zone
Canal Zone (abstract): Geol. Soc. America Bull., and Costa Rica: Idem, p. 103-116, pls. 46-52,
v. 24, p. 707-710. figs. 1-3.
Aside from omission of first two paragraphs, this Reissue, with slight changes, of 1917 publication
is a republication of the earlier "Canal Record" having same title. Reissued in complete volume,
account. 1919.


1918. Canu, Ferdinand, and Bassler, R. S., Bryozoa of the 1922. Olsson, A. A., The Miocene of northern Costa Rica:
Canal Zone and related areas: Idem, p. 117-122, Bull. Am. Paleontology, v. 9, no. 39, 309 p., 32 pls.
pl. 53. Includes mollusks from Gatun formation of Canal
Two species from Emperador limestone [member Zone and one species from Toro limestone member
of ('ulebra formation]. Reissued in complete of Chagres sandstone (Pecten macdonaldi).
volume, 1919. 1923. Vaughan, T. W., Studies of the larger Tertiary forami1918. Rathbun, M. J., Decapod crustaceans from the Panama nifera from tropical and subtropical America: Natl.
region: Idem, p. 123-184, pls. 54-66. Acad. Sci. Proc., v. 9, p. 253-257.
Species from Caimito [misidentified as Culebral, Includes Lepidocyclina miraflorensis from a loCulebra, and Gatun formations, and Pleistocene cality, apparently now submerged, evidently represtrata. Reissued in complete volume, 1919. senting La Boca marine member of PanamA
1918. Pilsbry, II. A., Cirripedia from the Panama Canal Zone: formation.
Idemn, p. 185-188, pl. 67. 1924. Hanna, G. D., Rectifications of nomenclature: Calif.
Five species from so-cllled Pliocene [Alhajuela Acad. Sci. Proc., 4th ser., v. 13, p. 151-186.
sandstone member of Caimito formation], Gatun Three new names are proposed for Canal Zone
formation, and Pleistocene strata. Reissued in fossil mollusks.
complete volume, 1919.
1919. Vaughan, T. W., Contributions to the geology and pale- 1924. National Academy of Sciences, Report of the Committee
ontology of the Canal Zone, Panama, and geologi- of the National Academy of Sciences on Panama
cally related areas in Central America and the West Canal Slides: Natl. Acad. Sci. Mem., v. 18, 84 p.,
Indies: U. S. Natl. Mus. Bull. 103, 612 p., 154 pls., 51 pls., 19 figs.
27 figs. Appendix B on geology, by MacDonald, includes
Separate parts of this volume are listed in present structure sections of part of Gaillard Cut. Appenbibliography as 1918 or 1919 items. dix C is a discussion of chemical and physical prop1919. Vaughan, T. W., Fossil corals from Central America, erties of Cucaracha formation.
Cuba, and Porto Rico, with an account of the Ameri- 1924. Vaughan, T. W., American and European Tertiary can Tertiary, Pleistocene, and Recent coral reefs: larger Foraminifera: Geol. Soc. America Bull., v.
Idem, p. 189-524, pls. 68-152, figs. 4-25. 35, p. 785-822, pls. 30-36, 6 figs.
Species from Caimito formation [misidentified as Includes Miogypsina cushmani, from Culebra forCulebra formation and Emperador limestone memn- mation, and M. panamensis from strata now referred
her], Culebra formation and Emperador limestone to Caimito formation.
member, and La Boca marine member of Panami 1924- Douvill6, Henri, Revision des LDpidocyclines: Soc. Gdol.
formation [misidentified as Emperador limestone 1925. France M6m., new ser., M~m. 2 (t. 2), 115 p., 7
member of Culebra formation] are described, and pls., 83 figs.
species from Pleistocene strata are listed. Includes Lepidocyclina canellei and L. chaperi,
1919. MacDonald, T). F., The sedimentary formations of the and a new species from upper valley of Rio Chagres,
Panama (Canal Zone, with special reference to the L. decorala, which has not been recognized in later
stratigraphice relations of the fossiliferous beds: collections (see Cole, 1952, [1953], p. 3).
Idem, p. 525 -545, pls. 153, 154, figs. 26, 27. 1925. Dall, W. IT., Illustrations of unfigured types of shells in
The name "Chagres sandstone" is proposed. the collections of the United States National MuAside from that new name and slight changes in scum: U. S. Natl. Mus. Proc., v. 66, art. 17, 41 p.,
some age assignments, discussion of stratigraphy is 36 pls.
essentially similar to that in MacDonald's 1915 ac- Includes a Pliocene species (Sthenorytis toroense)
count. Includes measured stratigraphic sections. and two Pleistocene species (Corbula macdonaldi and
1919. Vaughan, T. W., The biologic character and geologic cor- Yoldia perprotracta) described by Dall in 1912.
relation of the sedimentary formations of Panama 1925. Maury, C. J., A further contribution to the paleontology in their relation to the geologic history of Central of Trinidad (Miocene horizons): Bull. Am. PaleonAmerica and the West Indies: Idem, p. 547-612. tology, v. 10, no. 42, 250 p., 43 pls.
Paleontology, age, and correlation of formations Includes a species from Culebra formation (Scain Canal Zone. pharca balboai) and two from Gatun formation
1919. Sears, J. D., Deposits of manganese ore near Boqueron (Scapharca dariensis and Clementia dariena).
River, Panama: U. S. Geol. Survey Bull. 710, p. 1926. Hodson, Floyd, Venezuelan and Caribbean Turritellas:
85-91, figs. 1-3. Idem, v. 11, no. 45, 50 p., 30 pls.
Manganese prospects near Rio Boquer6n. South- Turritella altilira is illustrated.
ernmnost prospect is shown on plate 1 of present 1926. Vaughan, T. W., The stratigraphic horizon of the beds report. containing Lepidocyclina chaperi on Haut Chagres,
1921. Berry, E. W., A l)alm nut from the Miocene of the Canal Panama: Natl. Acad. Sci. Proc., v. 12, p. 519-522.
Zone: U. S. Natl. Mus. Proc., v. 59, p. 21-22, 3 At type locality, San Juan de Pequeni in upper
figs. Chagres valley (locality 3 of present report),
Found in Gatun formation. Lepidocyclina chaperi is associated with upper
1921. Cooke, C. W., Orthaulax, a Tertiary guide fossil: 1. S. Eocene species.
Geol. Survey Prof. Paper 129, p. 23-37, pls. 2-5. 1926. Woodring, W. P., American Tertiary mollusks of the
Orthaulax gabbi is recorded from Caimito forma- genus Clementia: U. S. Geol. Survey Prof. Paper 147,
tion [not so specified] and Culebra formation. p. 25-47, pls. 14-17, 1 fig.


Includes Clementia dariena, which occurs in Gatun 1936. Tucker, 11. I., The Atlantic and Gulf coast Terln iry
formation and is doul)btfully recorded from Culebra Pectinidae of the United States: Am. Midland
formation. Naturalist, v. 17, p. 471-490, 4 pls.
1927. Vaughan, T. W., Larger Foraminifera of the genus Includes Pcten macdonaldi, from Toro lirnest one
Lepidocyclina related to Lepidocyclina manelli: U. S. member of Chagres sandstone.
Natl. Mus. Proc., v. 71, art. 8, 5 p., 4 pls. 1937. Coryell, 1. N., and Embich, J. R., The Tranquilla shale
Includes Lepidocyclina miraflorensis. (upper Eocene) of Panama and its foraminiferal
1927. Palmer, K. V. W., The Veneridae of eastern America, fauna: Jour. Paleontology, v. 11, p. 289-305, pls.
Cenozoic and Recent: Palaeontographica Ameri- 41-43, 1 fig.
cana, v. 1, no. 5, 428 p., 45 pls. Foraminifera from a locality on Rio Chagres,
Includes described fossil species from the Canal now flooded by Madden Dam.
Zone. 1937. Coryell, 11. N., and Fields, Suzanne, A Gatun ostracode
1927. Hodson, Floyd, IHodson, H1. K., and Harris, G. D., fauna from Cativa, Panama: Am. Mus. Novitates
Some Venezuelan and Caribbean mollusks: Bull. 956, 18 p., 47 figs.
Am. Paleontology, v. 13, no. 49, 160 p., 40 pls. Ostracodes from lower part of Gatun formation.
Includes species from Gatun formation. 1941. Vaughan, T. W., and Cole, W. S., Preliminary report on
1929. Anderson, F. M., Marine Miocene and related deposits the Cretaceous and Tertiary larger Foraminifera of
of north Colombia: Calif. Acad. Sci. Proc., 4th ser., Trinidad, British West Indies: Geol. Soc. America
v. 18, no. 4, p. 73-213, pls. 8-23. Special Paper 30, 137 p., 46 pls., 2 figs.
Includes mollusks collected from Gatun formation Includes Operculinoides panamensis.
at spillway of Gatun Dam. 1941. Merriam, C. W., Fossil Turritellas from the Pacific coast
1930. Li, Chih Chang, The Miocene and Recent Mollusca of region of North America: Calif. Univ., Dept. Geol.
Panama Bay: Geol. Soc. China Bull., v. 9, p. 249- Sci., Bull., v. 26, no. 1, p. 1-214, pls. 1-41, 19 figs.
279, 8 pls., map. Turritella altilira is illustrated.
Includes species characteristic of Gatun forma- 1942. Olsson, A. A., Tertiary deposits of northwestern South
tion, stated to have been dredged at Pacific entrance America and Panamd: Eighth Am. Sci. Cong. Proc.,
to canal. v. 4, p. 231-287.
1930. Rutsch, R., Einige interessante Gastropoden aus dem Tertiary formations of Panam.
Tertihir der Staaten Falc6n und Lara (Venezuela): 1943. [Thompson, T. F.], Geology: Panama Canal, Dept. OperEclogae Geol. Helvetiae, Band 23, p. 604-614, pl. 17. ation and Maintenance, Special Eng. Div., Third
Type of Distorsio gatunensis is discussed and Locks Project, pt. 2, chap. 3, 33 p., 21 figs.
illustrated. General discussion of geology of Canal Zone.
1930. Reeves, Frank, and Ross, C. P., A geologic study of the 1943. [Thompson, T. F.], Foundations and slopes: Idem, pt. 2,
Madden Dam project, Alhajuela, Canal Zone: U. S. chap. 5, 138 p., 6 pls., 136 figs.
Geol. Survey Bull. 821, p. 11-49, pls. 4-13, figs. 1-5. Detailed geology of Third Locks sites.
Geology of Madden Dam site and area to be 1944. Thompson, T. F., Geological explorations in the vicinity
flooded by Madden Lake. of Rio Quebrancha for the Panama Cement Com1931. Pilsbry, H. A., The Miocene and Recent Mollusca of pany: Panama Canal, Dept. Operation and MainPanama Bay: Acad. Nat. Sci. Phila. Proc., v. 83, tenance, Special Eng. Div., 34 p., 10 pls., 4 figs.
p. 427-440, pl. 41, 3 figs. Geology of part of Quebrancha syncline, east of
Eight of the species described by Li in 1930 are Canal Zone.
Miocene fossils. One (Clementia dariena) is labelled 1945. Nicol, David, Restudy of some Miocene species of "Gatun Locks and Spillway" and all have matrix Glycymeris from Central America and Colombia:
characteristic of Gatun formation at and near Gatun. Jour. Paleontology, v. 19, p. 622-624, pl. 85.
1931. Hodson, Floyd, and HIodson, H. K., Some Venezuelan Includes Glycymeris canalis.
mollusks: Bull. Am. Paleontology, v. 16, no. 59, 1946. Vaughan, T. W., Initiation of geological investigations in 94 p., 24 pls. the Panama Canal Zone: Science, v. 104, no. 2696,
Includes Mlacoma gatunensis. p. 209
1932. Vaughan, T. W., and Cole, W. S., A new species of Geologic investigations during construction period
Geologic investigations during construction period Lepidocyclina from the Panama Canal Zone: Wash- after 1910 are attributed to a suggestion from
ington Acad. Sci. Jour., v. 22, p. 510-514, 9 figs. Lord Bryce to President Taft.
Lepidocyclina pancanalis is described. The type
locality, which is also the type locality of Miogypsina 1946. Keen, A. M., and Thompson, T. F., Notes on the Gatun panamensis and Nummulites panamensis, represents formation (Miocene), Panama Canal Zone (abstract):
panamensis and Nummulites pana mensis, represents Go.Sc mrc ulv 7 .120
Caimito formation, but is not so specified [locality Geol. Soc. America Bull., v. 57, p. 1,260.
56 of present report]. Three faunal zones are recognized.
1933. Vaughan, T. W., Studies of American species of Foram- 1947. Nicol, David, Tropical American species of Glycymeris
inifera of the genus Lepidocyclina: Smithsonian from the Tertiary of Colombia, and a new species
Misc. Coll., v. 89, no. 10, 53 p., 32 p1s. from Panama: Jour. Paleontology, v. 21, p. 346-350,
Includes Lepidocyclina canellei and L. vaughani. pl. 50.
1934. Collins, R. L., A monograph of the American Tertiary Includes Glycymeris schencki from Gatun formapteropod mollusks: Johns Hopkins Univ., Studies tion.
in Geology, no. 11, p. 137-234, pls. 7-14. 1947. MacDonald, D. F., Panama Canal slides: Panama Canal,
Includes a species from Gatun formation, Vagi- Dept. Operation and Maintenance, Special Eng.
nella caribbeana. Div., Third Locks Project, 73 p., 52 pls., 5 figs.


A posthumous publication. Discussion of geology 1953. Cole, W. S., Some late Oligocene larger Foraminifera from
includes some modification of MacDonald's earlier Panama: Jour. Paleontology, v. 27, p. 332-337, pls.
views. Geology of slide area in Gaillard Cut is 43, 44.
shown on detailed map (scale, 1 inch=465 feet). Species in MacDonald's collections from Culebra
1947. [Thompson, T. F.J, Geology: Panama Canal, Rept. formation, including Emperador limestone member,
Governor under Public Law 280, 79th Cong., 1st and La Boca marine member of Panama formation.
Sess., Annex 3, 30 p., 8 figs. 1954. Bramlette, M. N., and Riedel, W. R., Stratigraphic value
Geology of proposed sea-level canal is summarized, of discoasters and some other microfossils related to
1947. [Thompson, T. F.], Geology: Idem, App. 8, 84 p., 38 figs. Recent coccolithophores: Jour. Paleontology, v. 28,
Geology of proposed sea-level canal. Areal geology p. 385-403, pls. 38-39, 3 figs.
is shown on strip maps, scale 1:40,000 and 1:20,000. Includes records of discoasters from Gatuncillo
1948. Cooke, C. W., Eocene echinoids from Panama: Jour. and Culebra formations.
Paleontology, v. 22, p. 91-93, pl. 22. 1955. Woodring, W. P., Geologic map of Canal Zone and adEocene echinoids collected in Madden basin during joining parts of Panama: U. S. Geol. Survey, Misc.
field work for present report. Geol. Invest., Map I-1, scale 1:75,000.
1949. Woodring, W. P., and Thompson, T. F., Tertiary forma- Reproduced with minor alterations as plate 1 of
tions of Panama Canal Zone and adjoining parts of present report.
Panama: Am. Assoc. Petroleum Geologists Bull., 1956. Terry, R. A., A geological reconnaissance of Panama: v. 33, p. 223-247, 2 figs. Calif. Acad. Sci. Occasional Paper 23, 91 p., 3 pls.,
Summary of stratigraphy and paleontology of 8 figs.
Tertiary formations. A general account of the geology of Panama,
1949. Cole, W. S., Upper Eocene larger Foraminifera from the including Canal Zone. Published after present
Panama Canal Zone: Jour. Paleontology, v. 23, p. report was prepared.
267-275, pls. 52-55. 1957. Cole, W. S., Late Oligocene larger Foraminifera from
First published record of Eocene deposits in Canal Barro Colorado Island, Panama Canal Zone: Bull.
Zone. The fossils were collected at locality 29 of Am. Paleontology, v. 37, no. 163, p. 309-338, pls.
present report. 24-30.
1949. Bermidez, P. J., Pavoninoides, a new genus of the Milio- Description of species from Bohio and Caimito
lidae from Panama: Cushman Lab. Foram. Research formations of Barro Colorado Island.
Contr., v. 25, pt. 3, p. 58, 1 fig.
Pavoninoides panamensis, from "marly limestone GEOLOGY
of the Oligocene (probably middle), Madden Lake." STRATIGRAPHY
Though the locality is indefinite, the limestone pre- OUTLINE OF STRATIGRAPY
sunmably is in Gatuncillo formation.
1949. Rubio, Angel, Notas sobre geologfa de Panam6: Panam6, The region covered by plate 1 embraces all except the
Ministerio de Educaci6n, Depto. de Cultura y Pub- extreme western part of a Tertiary marine sedimentary licaciones, 183 p., 32 figs. area which may be designated the central Panamai
Compilation of data on geology of Panama.
area (fig. 1). The boundaries of the areas shown in 1950. Pilsbry, H. A., a)d Olsson, A. A., Review of Anticlimax, a
with new Tertiary species (Gastropoda, Vitrinelli- figure 1 represent the approximate known extent of dae): Bull. Am. Paleontology, v. 33, no. 135, 22 Tertiary marine formations, not the outlines of deposip., 4 p)ls. tional basins. In the central PanamA area, Tertiary
Includes Anticlimax gatunensis and A. telcospira, marine formations extend across the continental divide.
from lower part of Catun formation.
from lower part of Ga tun formation. The stratigraphy in the region covered by plate 1
1950. Jones, S. M., Geology of Gatun Lake and vicinity, T
Panama: Geol. Soc. America Bull., v. 61, p. 893-922 is notably different from place to place. For the 2 pls., 2 figs. purpose of description six main regions are recognized:
Geology of (atun Lake area. Includes a geo- Quebrancha syncline, Madden basin, Gatiun Lake area,
logic mapl), scale 1:125,000. Caribbean coastal area, Gaillard Cut area, Pacific
1952. Drooger, C. W., Study of American Miogypsinidae, So coastal region in Panami cast of the Canal Zone.
p., 3 pls., 14 figs., Zeist, Netherlands.
includes species from Caimnito formation and Quebrancha syncline and Madden basin are structural
Culebra formation, including Emperador limestone features east of the Canal Zone. Gaillard Cut, designmemb)er. nated Culebra Cut during the construction period, is
1952. Thompson, T. F., Ring dikes of the continental divide the part of the canal excavation beginning opposite the
region, Panama Canal Zone (abstract): Geol. Soc. south end of the Panama Railroad bridge across Rio
America Bull., v. 63, p). 1346, 1952. s t t a a d ig ssR
iting-sliaped and cup-shaped dikes surrounding Clagres at Gamboa and extending southeastward,
hills of agglomerate in (Gaillard Cut area, across the continental divide, to the north end of 1953. Cole, W. S., Eo eie anid Oligocene larger Foraminifera Pedro Miguel Locks. The correlation of the forminations
from the Panama Canal Zone and vicinity: U. S. in different areas is shown in figure 4.
Geol. Survey Prof. Paper 214, 41 p., 28 pls., 2 figs.,t on which the Tertiary formations rest
1952 [19531. The basement o which the Tertiary formations rest
Eocene al(l Oligocene larger Foraminifera col- consists principally of altered and strongly deformed
elected (urin g field work for present report. volcanic rocks, including tuffs that contain marine

P Ch C R I B! E A Ns

Punta Manzanilla

Put Snt iaafl


V0 Put V'una Naanj

U i PA, AMAr>, Ae4up~j EA
U~~vL'W"' dpcI w

FIUR .-a o anm~ hoig inepl resofTrtay irie eimnar oraios n ae cvre y lae1.BsefomAerca eorphcl oiey' 1otttl apofHspnFOmriS


fossils. The volcanic rocks are intruded by dioritic The upper part of the Caimnito formation of Madden rocks. This basal complex is probably of Cretaceous basin, including the formally named Chilibrillo limeage, but so far all that is known about its age, in the stone and Alhajuela sandstone members, consists of region covered by pla e 1, is that it is older than middle marine deposits of early Miocene age. Nonmarine and Eocene. It is much older than MacDoaald's (1913, marine lower Miocene deposits in the Gaillard Cut area pl. 4) igneous complex-a map term he used for vol- are subdivided into relatively thin formations: in ascendcanic and intrusive rocks of Oligocene and early ing order, the Culebra formation (including the EmMiocene age. perador limestone member), the Cucaracha formation,
The middle and upper Eocene Gatuncillo formation and the Panami formation (including the La Boca rests with marked unconformity on the basement marine member and Pedro Miguel agglomerate memrocks. It has been identified east of the Canal Zone ber). These three formations contain more volcanic and in the eastern part of the Zone. Lithologically it material than supposedly equivalent deposits in Madden is more uniform than the Oligocene and lower Miocene basin. The marine Culebra formation transgresses formations. northward across the Las Cascadas agglomerate.
Formations of known or inferred Oligocene age are According to present interpretations, the La Boca of wide extent and very heterogeneous. They are marine member of the Panam' formation interfingers
marine and nonmarine, volcanic and nonvolcanic, at with the upper part of the Cucaracha, or overlaps the least nonvolcanic aside from tuffaceous debris. They Cucaracha and Culebra formations and rests on the Bas represent all of Oligocene time and for the most part Obispo. All three formations and some of the lower arc conformable to each other and to the Gatuncillo Miocene of Madden basin are assigned to the upper formation. In the Pacific coastal area, however, the Oligocene by some paleontologists. Bohio formation overlaps the Gatuncillo formation and The two Tertiary formations younger than those of in the northern part of Madden basin the Caimito early Miocene age are found only in the Gatun Lake formation overlaps the Bohio. Except in the Gaillard and Caribbean coastal areas. These youngest formaCut area, the Oligocene formations are marine or partly tions are marine and, like the Eocene Gatuncillo formamarine: the Bohio and Caimito formations. Though tion, are more uniform lithologically than those of the Bohio formation (the older of the two) appears Oligocene and early Miocene age. The middle and to be for the most part nonmarine, marine strata are upper Miocene Gatun formation is famous for its wellfound in it at different horizons. Isolated outcrops in preserved fossils. Though the field relations between the Gatun Lake area, inferred to represent a tongue of the Gatun and Caimito formations are unknown, the marine strata in the lower part of the Bohio formation, two formations evidently are separated by a disconcontain mollusks considered of ea1y Oligocene age and tinuity and perhaps by slight discordance. East of the larger Foraminifera assigned to the late Eocene. Canal Zone the Gatun overlaps onto the Cretaceous(?) Smaller Foraminifera of early Oligocene age are found basement. The Gatun of the region covered by plate 1 in the basal part of the Bohio in the Quebrancha is considered to be middle Miocene. The Gatun at the syncline. In both the Gatun Lake and Pacific coastal west, end of the outcrop area, about 50 kilometers areas thin marine deposits in the upper part of the southwest of Col6n, in the western part of the region Bohio contain late Oligocene fossils. The Caimito shown in figure 3, is assigned to the late Miocene. formation overlies the Bohio and is for the most part The lower Pliocene Chagres sandstone is the youngest marine. Late Oligocene fossils, particularly larger of the Tertiary formations. It overlies and partly Foraminifera, are wid(lespread in the Caimito. In overlaps the Gatun formation. The thin Toro limeMadden b)asii, however, the lower part of the formation stone member lies at the base of the Chagres in the is late Oligocene and the upper part is early Miocene. eastern part of the outcrop area.
In the Gaillard Cut area the place of the Bohio and All the Tertiary formations are somewhat tuffaceous Caimito formations apparently is taken by the wholly but the oldest and youngest contain the least tuffaceous noimarine and volcanic Bas Obispo formation and Las debris, the Oligocene and lower Miocene the most. Cascade s agglomerate. They aire considered Oligo- Moreover, the Oligocene and lower Miocene formations c(,ne(?) on the basis of their inferred relations to the show a progressive southwestward increase in volcanic Bohio and Caimiito formations. The BasObispo forma- and intrusive rocks, until in the southwestern part of tion -the older of the two-seems to grade north- the region covered by plate 1 there is nothing but westward into the Bohio formation. The Las Cascadas volcanic and intrusive rocks. The change is strikingly agglmjnera te is thought to be lhe equivalent of the lower shown on plate 1; in fact, more so than would be the pairt, or perhaps all, of the Caimito formation of the case if the map were equally detailed throughout. The (Gaitn liake area. volcanic rocks themselves and also the intrusive rocks


are undifferentiated in the southwestern part of the associated rocks throughout the (Caribbean region map area. Ihese undifferentiated rocks, however, (Woodrinig, 1954,1)p.722-725). Late (Cretaceous Fornmadjoin a strip along the canal where greater detail is inifera (Globotruncana and ihmbelita) are reportedjto shown than elsewhere on the map. have been found in northwestern Paniami, near the
Costa Rican border, in siliceous limiestonie that. preCRETACEOUS(?) SYSTE sumably represents the same major unit as the baseThe oldest rocks in the Canal Zone and nearby, much ment rocks of plate 1. The basement, however, may older than any seen along the canal, are chiefly altered include rocks older and younger than Cretnceous. The lavas and dioritic rocks. 'ihese extrusive and intrusive altered tuffs samp)led near Rio Gatin are not the kinds rocks are briefly described or mentioned under the of rocks that would be chosen as being likely to contain heading "Igneous rocks." Altered tuffs and other fossils. Yet thin sections of the three types sampled altered sedimentary rocks are associated with the lavas. show indeterminable Foraminifera and Radiolaria. If None of these rocks, sedimentary or igneous, was further work on the basement rocks is undertaken, it
studied during the field work and they were observed doubtless is only a matter of time until identifiable only casually. They crop out in the eastern part of fossils are found. The siliceous limestones are particthe Zone and extensively in PanamA east of the Zone, ularly promising for microscopic fossils. making up the basement on which the Tertiary formations rest. This basement on the borders of Madden EOCENE SERIES
basin was designated the volcanic complex by Reeves GATUNCILLO FORMATION
and Ross (1930, p. 18). Formations of Paleocene and early Eocene age are
Everywhere the basement forms high, rugged forested unknown in the central Panamnti area. They may, uplands and mountains. The composition, structure, however, be represented in the basement complex or by and age of these rocks are important aspects of Pana- overlapped deposits in the structurally deeper parts of manian geology that remain to be studied. Contrary the area. The oldest known Tertiary formation is the to the expectation of geologists not familiar with the Gatuncillo formation, which lies directly on the Cretropics, the high-gradient streams in the rugged terrain taceous(?) basement. characteristic of the basement offer a wealth of rock The Gatuncillo formation was named by Thompson outcrops. Moreover, the streams are so numerous that (1944, p. 12-13) as the Gatuncillo shale. The type a closely spaced network of outcrops is available, region is in the valley of Rio Gatuncillo on the east
Strongly deformed altered tuffs were seen at a few limb of the Quebrancha syncline. The name Tranlocalities. Three samples of different grain size, rang- quilla shale has priority, but that name was defined ing fiom very fine-grained to very coarse and agglomer- inadequately, principally on the basis of foraminiferal atic, were collected on the Transisthmian Highway 2 samples from a locality in Madden basin later flooded kilometers east-southeast of the bridge across Rio by Madden Dam (Coryell and Embich, 1937, p. 289; Gatin. They were examined by W. S. Burbank, who for location of Tranquilla see Reeves and Ross, 1930,
found them to be moderately to strongly bchloritized pl. 5). and carbonatized. The coarse-grained rock contains The Gatuncillo crops out in the eastern part of the
andesiticandlatitic fragmentsandsomedevitrifiedglass. Canal Zone and east of the Zone. It forms rolling The two samples of finer grain contain angular frag- lowlands, which stand in contrast to the rugged upments of feldspar, pyroxene, iron oxides, and quartz. lands characteristic of the basement complex. The These rocks of finer grain are sheared and fractured, thickness of the Gatuncillo is estimated to range from and cut by veinlets of calcite and a colorless mineral, 150 to 800 meters. The formation unconformably probably a zeolite. overlies the Cretaceous(?) basement. In the type
Sedimentary and pyroclastic rocks of the basement region and in other areas wherever the succession is complex at the Hyatt manganese prospects near Rio complete, the Gatuncillo is conformably overlain by Boquer6n, the southernmost of which is shown at the the Bohio formation. In Madden basin, however, north edge of the general geologic map (pl. 1), consist of the Bohio is overlapped by the Caimito formation. siliceous limestone, quartzite, sheared agglomerate, and In the Pacific coastal area the Gatuncillo does not fine-gramined tuff(?) altered to schist (Simons, in appear between the basement and the Bohio formation, Roberts and Irving, 1957, p. 121, 124). being overlapped by the Bohio. Collections of larger
Though the age of the basement rocks is unkown- Foraminifera sent to T. W. Vaughan many years ago other than that they are older than the unconformably by A. A. Olsson and R. A. Terry indicate that Eocene overlying middle and late Eocene deposits-they deposits reappear farther east in the Pacific coastal probably are Cretaceous, like widespread volcanic and area in the valley of Rio Bayano, 45 kilometers east-


northeast of the eastern edge of the area shown on those off the north side of the Transisthmian Highway
plate 1 (Terry, 1956, p. 32). 50 meters east of the bridge across Rio Gatuncillo
Though the Gatuncillo consists chiefly of mudstone (locality 20) and along the road leading southward from and siltstone, it includes bentonitic mudstone, sand- the Transisthmian Highway to Nuevo San Juan
stone, and limestone, and at the base conglomerate of (localities 22, 23). On Quebrada Fea (the stream on variable thickness, the east side of Rio Gatuncillo valley 4 kilometers
northeast of the Transistuhinian Highway bridge across
STRATIG;RAPHY AND LITHOLOGY Rio Gatuncillo), however, algal-foraminiferal limestone
Rio Agua Sucia area.-The Rio Agua Sucia area has a thickness of at least 10 meters. Conglomerate
lies west of the Quebrancha syncline, between the and sandstone at the base of the formation are exposed
Azota Caballo and the Agua Sucia faults. Before on the Transisthmian Highway. The conglomerate,
it was realized that the deposits in the Rio Agua resting on Cretaceous(?) altered volcanic rocks, has a
Sucia area are of Eocene age, the name Rio Duque thickness of 30 to 90 centimeters and is made up of
shale was proposed for them (Thompson, 1944, pebbles and cobbles of altered volcanic rock. It is
p. 21-23). The area is crossed by the Trans- overlain by soft medium- to fine-grained sandstone
isthmian Highway. Cuts along the highway ex- grading upward into soft silty fine-grained sandstone.
pose minudstone, siltstone, and sandstone of the The thickness of the sandstone is 6y meters. Gatuncillo formation. Mudstone and siltstone are M1adden basin.-The largest outcrop area of the
more prevalent in the southeastern part of the area, Gatuncillo formation is in the northern and northsandstone in the northwestern part. The mudstone is eastern parts of Madden basin. Much of the outcrop mniore silty than in the Quebrancha syncline; sandstone area, however, is flooded by Madden Lake. The
is more prevalent than in other areas; and northwest- Eocene deposits of Madden basin were included in the ward, which also is stratigraphically upward, the sand- Bohio formation by Reeves and Ross (1930, p. 17-18), stone is of coarser grain than in other areas. Sand- although they are strikingly unlike those of the Bohio. stone at locality 27 is medium-grained, poorly sorted, The thiclkness of the formation is difficult to estimate, and contains much carbonaceous debris. The strata but probably is not more than 300 meters.
at locality 28 consist of poorly sorted gritty sandstone. Limestones are more extensive and individual units The northwestward increase in grain size suggests that of limestone are thicker than in other areas. As elsethe depositional margin of the central Panami area where, algal or algal-foraminiferal limestone is most
was not far to the north. common, but other kinds of limestone are repreSo far as observed, limestone is not common. Algal- sented. Algal and algal-foraminiferal limestone in foraminiferal limestone, about 15 meters thick, forms the upper part of the Gatuncillo at locality 14 is fully a little hill at locality 25, and foraminiferal limestone 30 meters thick. It is separated by sandy strata from crops out at locality 23a. an overlying algal limestone that reaches a thickness of
Ouebrancha syncline.-In the type region, on the about 15 meters. Similar algal limestone, also about
east flank of the Quebrancha syncline, the maximum 15 meters thick, forms the natural bridge (puente
thickness of the Gatuncillo formation is estimated to natural) on Rio Puente. A cliff on the north side be 800 meters, apparently greater than in other areas. of Rio Puente, 800 meters in a direct line upstream An earlier estimate of 3,(0O feet (900 meters) probably from the natural bridge, exposes almost the same is excessive (Woodring and Thompson, 1949, p. 227). thickness of limestone. Silty somewhat fissile echinoidFiue-grained rocks mudstone and siltstone- make up bearing limestone (plate 4), soft yellowish marly limethe bulk of the formation. Limestone, bentonic mud- stone, moderately soft coralliferous limestone, and stone, sal)(dstone, and conglomerate are minor con- hard algal limestone, all representing a thickness of 10 slitu ens. Typical fine-gr'ained rocks are readily acces- meters, are exposed in a partly demolished hill at sible on Rio Quebrancha about 100 meters upstream locality 11. There are numerous other exposures
from the TransisthiIian Highway bridge (locality 21). of limestone in Madden basin; in fact, all the fossils The limestones are algal and foraminiferal and most of from that area were found in limestone. That limethem have a thickness of less than a meter, such as stone may occur at the base of the formation is shown by the following section measured on the south
I The localitics at which fossils wei t collected are listed on pages 112-130 and, un- .
is otherwiseo specified in the list, are lto niu the general geologic map (pl. 1). side of Rio Pequeni:


Section of basal part of Gatuncillo formation on south side of Rio basin of Rio Frijol and the smaller area farther east.
Pequeni near head of Madden Lake (locality 1) The thickness of the formation along Rio Frijol is Gatuncillo formation: Maers estimated to be between 300 and 400 meters. The
Limestone, thin-bedded nodular-weathering; low- lithologic types are similar to those elsewhere: mudest 1 meter more granular and somewhat sandy. stone, siltstone, sandstone, and thin beds of limestone.
Scattered angular pieces and few pebbles of base- Some of the sandstone contains carbonaceous debris.
ment rocks (diameter of largest 8 centimeters)
throughout lower half, more numerous in some For a discussion of the Gatuncillo formation in the
layers. Lepidocyclina abundant; many Yaberinella Gatun Lake area seaward from the Rio Frijol area
in one layer. Collection (locality la) 3 to 4.5 see page 61.
meters above base ----------------------------10. 6 Gamboa area.-A narrow band of Gatuncillo rocks
Unexposed (possibly sandy or silty strata) --------- 1. 5 lies in the lowland north of the high ridge north of
Limestone, thin-bedded, in thicker beds than overlying limestone. Contains Lepidocyclina and Gamboa. The strata dip northeastward and appear to
Yaberinella. Collection (locality 1) 0.5 meter be overlain in normal succession by the Bohio formaabove base ----------------------------------- 1. 5 tion. If the high ridge is underlain by basement rocks,
Unexposed (possibly sandy or silty strata) -------- 1.5 as shown on plate 1, and if the Gatuncillo is not Limestone, few boulders of altered volcanies at base .5 bounded by faults to the south or north, the thickness Basement of altered volcanic rock.
Basement of altered volcanic rock. of the Gatuncillo is not more than 150 meters. The
Thickness of section ----------------------15. 6 only outcrop of the Gatuncillo seen in this area consists
of calcareous mudstone containing a thin layer of Fine-grained and sandy rocks presumably make up limestone (locality 37).
the bulk of the formation. Fine-grained rocks are not Rio Casaya area.-Outerops of fossiliferous rocks of
readily accessible, but they doubtless could be found the Gatuncillo formation were found by R. H. Stewart by traversing streams. Sandy strata form a treeless along Quebrada de Oro, a northwestward-flowing
area surrounding locality 11 and sandy strata in the tributary of Rio Casaya about 4 kilometers southeast
upper part of the formation near locality 13 include of Gamboa (locality 38). The stream may be
practically pure quartz sand. recognized by mine-machinery debris and caved adits.
Rio Agua Salud area.-The Rio Agua Salud area is Limestone, sandstone, and siltstone of the Gatuncillo
the long, narrow strip of the Gatuncillo formation on formation are intruded by dacite porphyry. These the upthrown side of the Chinilla fault, in the eastern sedimentary rocks are partly silicified. They probably part of the Canal Zone. Coring along the alinement are faulted against the Caimito formation, although no
for a diversion channel for Rio Chagres-part of the fault is shown on plate 1.
Sea-level Canal project-showed the presence of the No outcrop areas of the Gatuncillo formation are
Gatuncillo formation in this area, the first record of known southwest of the Rio Casaya area. Though Eocene deposits in the Canal Zone. R. H. Stewart the formation seems to be thinning southwestward, it
and T. F. Thompson recognized larger Foraminifera may extend farther in that direction beneath the
of the Gatuncillo formation in cores from core hole Oligocene and lower Miocene strata penetrated by the SL84 (locality 29), drilled in 1947, and in float limestone canal and the undifferentiated volcanic rocks farther at the core-hole locality. Their age identification was southwest. confirmed by W. S. Cole, who described the Foraminifera (Cole, 1949). The three localities in the Rio FOSILS AND AGE.
Agua Salud area are core holes (localities 29-31), Smaller Foranmi fiera.-In most, of the areas smaller
which started and bottomed in the Gatuncillo forma- Foraminifera are abundant in mudstone and siltstone.
tion. The strata penetrated consist of mudstone, silt- Coryell and Eminbich described species collected at stone, silty sandstone, calcareous siltstone, silty lime- Tranquilla, a village on Rio Chagres flooded by
stone, and limestone. The depth of penetration ranged Madden Lake, and assigned the fauna to the upper from 30.7 to 54.1 meters. Eocene (Coryell and Embich, 1937). II. H. Renz and
Rio Frijol area.-The Rio Frijol area includes the P. J. Bermiddez kindly identified the following species
outcrop area of the Gatuncillo formation in the drainage in five samples:


Small( i' Fora mm if'ra from Gaba acilia formation *Smaller Foram in ifera from Galancillo formation-Continued
[Identifications by If. If. Remn and P. 4. Berna'idez] [Identifications by It. HI. Renz and P. J. Bermfihez]

Localities Localities
j ct'
el c, EL C lC

-- -~ -, --.I0,(I/IK ------------------------------------------------- ------- ----B ubnjncla Brady---------------------- --X -illomtirphina ~ ~ ~ ~ ~ ~ s ------------------------------------lL rss dObin------------------ ---Anqalcina paoractiesis Coryell and hvnai uhnnadBr
Linbich------------------------7 X > td--------Casiuaode p ---------------------- X-----------f.A lznni utal----------- X ahobosmia Braay------------- Cuha
sp ----------------------------- ----an H ris ----------------------- ---- X X X --A nm aith-------------------------- -----,-- -asdlnmc ----------- hlsoeamxin Ntl -------- ------7 ---Asac.a ., ala-Z-------N-tta---------------------- -- -- c.C mdaRus-----------------'rtblmn alznni --us----an
Sp -------rr --------------------------- 7 --annamod ------------------------------- -----C aodoCameana N-t--a---------- ----7- -- X
Bsolin ala--------------an-------- ------X---------------------e ou f. C .. omoidn Cush----- ----byrmeai ushan ------------ X --------- i)--------------------------------------- X---- X 7-Ilana---------n-a----------------- --- 7ndha an------------X lnauCsh nadJrvs--------------------Bo f.vB. aiaanlnis Cushman--n-----------------------hr---o-on------f x a-p-ru --us---byranmi C--s----a------------------ -------------------a anicde Stcaninf(Cshman)----------- ---- X 7 -gr.acilonis Cushman and Applin --------------------7f elonatni Cusa and Jarvis----------- ---7 -cf. B. gaciloeis Cushman and p- ------------------------- X---------------ppiin-----------X ------- -- Cibci cocoensisz -C-shman--------7 X X7-----jaculonasi Cushman and Ston -- X -------- 7n cf. u C' ocNiris (C----------- ------------ ---cf. B. cookeit Cushman andGdr
Stpon----------------------------- X------- -pi-nidu Berttez-----------------X ---- X7-mamla Coryhmland En1114 S ne-------------- ------ ---?nxcfC.pans a Nutail------------ ----------X-----cf. B. lcntrirosa Galloway and cf. C. pse udoun gcrian us (CushsI)--------------------------- x------ -- I--------- p ---------------------------- x---- x---- X
n p ~--------------------------------7 ---- 7 -Biim ina a (1(1zO(atsis Cushmian ---- x --- >
consan qa mca Parker amid 1r Ciazvalinoides cabinsis Cushman and
InrUdez----------------------- x K Bernidez-------------------------7 X X 7 X -cf. I, (00 pcrcnsis ('ushitnan- --- ----- --- --- havanensis Cushmuan and Berqli(tyabalensis Cole -------------- -- --- --- 11U(Idz------------------------------------- X-X --cf. B. immpe ndcns Parker an(I Ber- sp------------------------------------------7 X

mnue\ --- --- Corn usiira, olygogyra, Iantken of
Jaclksouc(nsii C('hib ---------C- an Cush --------------------------- ---- X-----------cf. B;. j(-i.'Vonc(sis var. canla t Cuyclam mina cf. C. pacifica, Beck ----------- >X X -Cumshnmn ------------ -- 81 -'___--------------------------x -------palm e rao IParker amd lh-rmiideiz -V - Denlalin a f. D. co man is d'()rigf X

(cf. B. palmicrac Pairk~er aimnd B 'r- cf. 1). (00 pcrenlsis ( smas n ---- --- --- --ma i'dez ------------------------------------ ef1.i eonat Neugeboren-- --' --V------Xa'ih ulxbgi XV s( iilacvis Ilantkemi ------- -If. It. jiyi a d'Or]iagnm ,v- Sp)------------------------------ x xx---- ---lax pa mcnis C olep ----------------- ---- ---- ----7x --sp-- ---1-- ----) isrorbis sp----------------------------- -


8nialler Foraininifera fronm Gutuncillo formation -Continued Snowlier Foram in ifera front Gaun Cillo f orifl (tiofl-( ont inutl
[Identifications by H. H. Ronz and P. J. Berm~dez] [Identifications by HI. HI. Renz antI P. J. Bermndezl

Localitie's Lti ties

cl v 7:

Doohacln rc N tal ---- -- --- --- X lnktiaaaa iessC si -cf. D. nutliC s m n--- - -- -- Y- u rstrlsB o nm
-- -- - - - - - - x xx Ilpo ha aods c. H ioln i

r e ) - - - - - - - - -. - - -p- - - - - -E-.sle i cf E7avg t (Reuss -- - x-- -aICId n ly ns( r in -

B o s - - - - - - YB r d e - - - - - - I X I C

Dorign(ylilda (euttzal) -------------------------- ----nnaaaac~s3Csnin--cf. ---n--------C ----a---------- ------- ---- supricisa (urulis ------ma --------- - --. 7 -sp--------------------------Nutall)-------- X--------'K Illoha oie e.I.dhonsi
Epolisglackdulin aia Cushager-------- ------- --- Cshma and--------n------------------mtcf.Erttan (Galloay and Mor- Iatgrnlaecnc utl
rndey)---------------------------- ----------------------Enosleiacf E ievgaa Ress -- Lijinna ceqoans ('Reuss -------- --- __ ---cf. maginta (alkecan L.rri~ uegnani (ilii andsn__Boys------------------- 7 > Brmuez------------------ -----------vrarg.ynat(Seguena)--ch--------------------------- chlsoa(es)-----sp--------------------------------- X
Fodc ri Eruteni Cshmn Hand Br--X --------mtiez------------------------------Laeni yl acucd REuss---------------------umbkonatuis (Russ)-n-------------< cf-- --- ----on (Wlla----)---vel. amd itiept Koch---- -- --- -- ----- --- -- -Gl n uln sp- - -- - - -- X7-
Fronieria tierenisa Hant------k--en-- -- s ---------------------------Lengudta suoaav h----jcsonni C------------------------ ------ x Lagndaria cf. sigmoidta NeuvGladuina.en ---er-------------------X ---S[)---------------------------------------------X------------------Glbiern --p-----s-s-Bo--i------------------------------oosoadli(sha)------I--cf.hteni Ho. andni Wallace------< ----SP---------inten (any)--------------- ----K < agnam f 1 brvuaNn

Ellisor ------------------------------ cf. G. hannai Cushmian and Ellisor -------------- X X f. Ml. suberassa Schwager ------------ sp --- ---- --- ---- --- --- ---- --- x --- ---cf. 31'. trianguluris var. punamcflsis Corvell and Embich ------------ ------>x
Oloborotalia centralis Cushman and Olobulina cf. G. gibba d'Orbigny -----------X------------ Alarginulinopsis cocoactisis (Cushmian)---rotundota (Bornexnann) -----------X------------------------------------ -------------------------------- ---- X------sp -------------------------------- x X -------- 31otanzia? sp----------------------- ---- ---- --------Kx
Giiinbelina. cubensis Palmer ----------- ---- X--------X Nodogenerina. heteroscuipta Bernv~dez------ X
Martini (Pjipers) ---------------- ---- ---- Gyroidinoides girardana (Reuss) ---------------- soldanji var. octocamerata (Cush- iultilineata (Borneinann) -------- ---------------
man and Hanna) --------------<


Smal% r Forarninifera fromn Gat uncillo formation-Continued Smaller Foraminifera from Gatuncillo formation-Continued
[Idenutificationis by 1H. H. Reoz aid 11. J. Bermnidez] jIdentifications by H. H. Renz and P. J. Bermfidez]

Localities Localities

.5 TI0 Cd. 0C3a

17 21 24 31 35 17 21 24 31 35

Nonion danvillense Howe and Wallace- X ---X X X Saracenaria acutanricularis (Fichtel
pornipilloides (Fichtel and Moll) --- -----X----------------and Moll) -----------------------X -------cf. V'. pornipilloides (Fiebtel and cf. S. hanikeni (Cushman -------- ---- ---- -------X
Moll) ------------------------------- X -----ef. S. latifrons (Brady) ---------------X X--------sp ----------------------------X X --X -- cf. S.schencki Cushman and Hobson --------------------------------- X------Orthiorph ma cf. 0. rohri (Cushman
and Stainforth) ------------------- -------- X-----------Shnkel f .ptoa(uha
Osangularia ?nexicana (Cole) ------------------X X --- and Bermiidez) ------------------- X ---------SI)---------------------------- x x------------- sp ------------------------------------ x------Planudaria sp ---------------------------------------X
Planulina, marialana Hladley --------------------------X Sigmoilina tennis (Czjzek) ----------------X ------solurala Cushman and Berrnidez- X-------X-----------Sigmomorphina sp ------------------ X -----X

Plectina, nuttalli Cushman and Stain- Siphogenerina sp ------------------------ X ---X -forh -------------------- --- --- --- X --- Siphonina advena Cushman -------------------X --- X
P fo---------------------------- ------- ------------- -tenuicarinata Cushman ---------- ---- ---- -----X
niorreyae Cushman -------------- ---- X ------ ihndsrac.S nuia(uh
t'auqlani Cushman --------------x X X X X --- poooaiae.S nulea(uh
Sp ------------------------------------x--------- man and Berrnidez)------------------------------- X
aff. S. curvatura (Cushman) ------ -------- -----X -Plea roslornella alternans Schwager -----X------- cf. S. dentaliniformis (Cushman
cf. plweae erndde ------ --- ---X --- ---and Jarvis) ---------------------------X--------cf. P. praegerontica Cushman and c.S utli(uha n
Stainforth -------------------------------------------Jarvis) ----------------------------------X -SI)-------------------------------- -------- pazicistriata (Galloway and Morrey) ---------------------------- X X--------Pseudo glandulina larvigata (d' Or- puintensis Corvell and Embich____ X -------bigny) -------------------------- ---- -------- ---cf. P. larvigata (d'Orbigny) --------------------X -- recta (Palmer and Berimidez) --------------X--------ot'ata (Cushiman and Applin) --------------X ---- aff. S. siibspinosa (Cushman) ------X -------radicula (Linii6)----------------- X---------------- vcrneu~li (d'Orbigny)------------- ---- -------- X X
cf. P. radicula (Linn6) --------------- X------- var. emaciata (Palmer and
SI)------------------------------ ---- x x -- Bermddez)------------------------------- X
p -- - - -- - - - X x -- X X
I'idlcvi c( f. P. bulloides (d'Orbigny) --- X----------- ---- Siphotcxhdlaria sp ------------------- ---- X------------p--------------------------- x ---- x x -Pyrgo pseudoinornata Cushman and Spirolocuilina cf. S. texana Cushman
Staiiiforth --------------------------- X----- -----------and Ellisor -------------------------- X ------sI)------------------------------------- X ---- x------ p ---------------------X------- ---- ---- X
Spiro plecta mrin a planuabs (Coryill
Quinqticlocutlina sp------------------------- ---- X ___ X and Embich) --------------------- X-------------X
Iobulu.s cf. Rt. dicanipylus (Franzenau) ----- ---- ------X -- Tc.xtularia hockleyensis var. rnalkinac
tcrryi Coryelt and Enihich ------- -----X----------------Corvell and Embich -------------------X----- ---- ---spp~~ ~ ~ ~ /------------- X x e f. T. recta Cushman ------------ X----------------RIol(Zalita flU'ficaifla Cushmn ----X -----X -- Textularia? sp ---------------------- X -----1----


Smaller Foraminifera from Gatuncillo formation-Continued of the pelagic species-with assemblages from other regions
Identifications by H. H. Renz and P. J. Bermddez] where the stratigraphic position and age are fairly well estabSlished. It should be mentioned, however, that the boundary Localities between the lower part of the upper Eocene and the upper part
o- f the middle Eocene, on the basis of smaller Foraminifera, is S uncertain throughout the Caribbean region.
S3 Two main upper Eocene faunal units are represented: an
S : earlier (localities 24, 31, 17, and 35) and a later (locality 21).
S The earlier unit itself suggests two minor units: the older repreSsented by localities 24 and 31, the younger by localities 17 and 35.
-_ The faunas from localities 24, 31, 17, and 35 are characterized
17 21 24 31 35 by the occurrence of Bulimina jacksonensis (or a related form), Globorotalia centralis, and Hantkenina alabamensis or H. supraTextulariella sp -------------------------------------X suturalis. They show distinct affinities with faunas of the
Triloculina cf. T. globosa (Hanna and Jackson group of southeastern United States, the Jicotea inmemHanna) ---- X------------ ber of the Jabaco formation and the San Luis formation of Cuba
cf. T. subrotundata (Montagu)__ .. -... X --------(Bermdidez, 1950, p. 249-258), the Pauji formation of Venezuela
sp ..----------------------------x x -------- (Nuttall, 1935), and the lower part of the Mount Moriah formation and the Hospital Hill marl in the San Fernando group of Uvigerina adelinensis Palmer and Trinidad (Cushman and Renz, 1948).
Bermddez ----------------------- X ------------ ---- The fauna from locality 21 has upper Eocene and lower
ef. U. atwilli Cushman and Simon- Oligocene affinities. It lacks Globorotalia centralis and Hantson ....----------------------------------------- X kenina. The presence of a form related to Bulimina jacksoncf. U. chirana Cushman and Stone X-------- X -- ensis, however, indicates a late Eocene age. This fauna suggests
curta Cushman and Jarvis ------------------- X X relationship with that of the Consuelo formation of Cuba
gardnerae var. nuttalliana Howe (Bermildez, 1950, p. 258-262).
and Wallace--------------------- X -----------Larger Foraminifera.-The first Eocene fossils from
spinicostata Cushman and Jarvis- X X X X Panama' were recorded in 1891, when Douvill& wrote spinulosa Coryell and Embich X ------------ that calcareous algae and heterostegine and orbitoid
cf. U. spinulosa Coryell and Em- that calcareous algae and heterostegine and orbitod
bich ------------------------------------x Foraminifera were found in limestone at San Juan in
sp.. ----------------------------x x --------x the upper Chagres valley (Douvill, 1891, p. 498, 499).
mexicanus (Nuttall) He thought the fossils to be of Oligocene age. By the
c. .Vaginu mexicanus (Nuttall) time his second note on the age of the beds along and
cf. V. mexicanus (Nuttall)--------------------ner.hecaalwa.h.tatth
sp ----------------------------- x near the canal was published, he recognized that the
Valvulineria cushmani Coryell and orbitoid found at San Juan represents the genus LepidEmbich -----------------------------------------X ocyclina (Douvill&, 1898, p. 598-599), later named
gasparensis Bermddez----------- ---- X ------------ L. chaperi as a tribute to the collector, an engineer of
Virgulina cf. V. danvillensis Howe and the first French canal company (Lemoine and R.
Wallace ....---------------------- ---------- X--------Douvill&, 1904, p. 14). In a still later publication
cf. V. dibollensis Cushman and Douvill reiterated the Oligocene age, as he was not
Applin....------------------------ X ------------ then aware of the presence of Lepidocyclina in the
cf. V. advena Cushman----------X X -------- Eocene (Douvill6, 1915, p. 129-130). At that time,
pachyheilus Hadley ---------------------X X -sp ------------- X however, he recorded the occurrence of a stellate
discocyclinid ("Asferodiscus") in association with Lepidocyclina in another sample of limestone from the upper Barring unknown structural complications and over- Chagres valley. Vaughan (1919b, p. 549, table oppolaps, localities 24 and 31 represent the lower third of site p. 595) left these strata in the Oligocene, despite the Gatuncillo formation, localities 17 and 35 the Cushman's suggestion (in a footnote to Vaughan's
middle third, and locality 21 the upper third. The table) that they should be referred to the upper Eocene.
following comments concerning the five samples were San Juan was located on Rio Pequeni and is submerged prepared by Messrs. Renz and Bermdidez: by Madden Lake. (For location see Reeves and Ross,
1930, pl. 5.) E. R. Lloyd collected at San Juan in A considerable number of species and varieties are unidenti- 1919 before Madden Dam was built (locality 3 of fled, either because they are undescribed or because comparative present report). When this collection was sent to material was not available.
The smaller Foraminifera in the five samples represent various Vaughan in 1926, he found that at its type locality levels in the upper Eocene. The age determinations are based Lepidocyclina chaperi is associated with late Eocene on a correlation of the faunas-with special emphasis on some species (Vaughan, 1926).


Larger Foramiaifera are the most abundant and wide- table of identified species, they were found in the area. spread fossils in limestone and calcareous mudstone of The partly silicified limestone that yielded mollusks the Gatuncillo formation. Loose specimens weathered under acid treatment also yielded many specimens
out of both kinds of rock are most suitable for identi- which probably are Lepidocyclina pustulosa. They are fication, as oriented thin sections can be prepared. At hollow, however, and therefore indeterminable. Float mainy localities these fossils weather out of hard lime- limestone in the Rio Casaya area contains somewhat stone because they are silicified or partly silicified, silicified specimens of a saddle-shaped Lepidocyclina, whereas the limestone is not silicified. Plate 3 shows probably L. chaperi. slective silicification and iron staining in a slab of lime- Samples of larger Foraminifera were collected at 27 stone collected at locality 14. At locality 13 specimens localities. Those from 15 localities were selected, on a of a small Lepidocyclina, probably L. pustulosa, are basis of favorable preservation and geographic and stratcompletely silicified and covered with beekite excres- igraphic range, for study by W. S. Cole, whose report cences, producing fantastic effects. Though no larger was published in 1953 (Cole, 1952 [1953]). His identiForaminifera from the Rio Casaya area appear in the fications are as follows:

Larger Foraminifera from Gata n rillo formation
[Cole, 1952 (1953), p. 4]

Localities I

Rio Rio GanmMadden basin Quebrancha syncline Rio Agua Agua Frijol boa
Sucia area Salud area area

I la 2 4 10 11 19 22 23 26 27a 28 29 33 37

Yalwrinclla jamacensis Vaughan ---------------------- X ---------------- ___-
Operculinoidcsfloridensis (Heilprin) -------------------------- -------- ---- --------------jacksonensis (Gravell and HIa) ------------------------------moodybranchensis (Gravell and Hanna)--------------------------- --- .-- -- ---orala s (Cushlm an) . . . . . .. . ------Vaughani (Cushlnman)---------------------------- ...-. .-----------------------Nammulites 2 striatoreticulatus L. Rutitn .-------- ---- ----. ..--- X .
IlHeterostegina ocalana Cutshman ---------- K -. .------
Fabiania cubensis (Cushlinan and Bermtidez)---------- 'X X -- x
Helicostagina soldadensis. (Grinsdale)-------------------------------------------------------- -- --

Lepidocyiclina (Lepidocyclina) montqomcriensis Cole-------------------- ---- ----
(Pliolepidina) gubernacula Cole ---------------------------------------------- x - --.
macdonaldi Cushman---------------------- X :. X .
pastulosa H. Douvill6---------------------- '-' X X X -------- x
pustulosa tobleri H. Douvill6-------------------- X x --------- -- 'K
(Nephrolepidina) chaperi Lemoine and R Douvih6 - -- -- K .

Ielicolepidina spiralis Tobler ------------------------------ ------ --- -- ---- 'K -Isltcroryclina georgiana (Cushman)---------------------------------------mnariannensis (Cushliman) ------------------------------ -------- --------- x---- -----minima (Cushlanan) ..-------------------------------------.----.. .. . 'K --
P'.seodophragmina (Proporocyclina) flintensis (Cushman) ------------------------------------- _..- ---The locality numbers in Cole's publication are field numbers. For correlation with report numbers of present report see p. 112-116.
Cited by Cole as Camerina.


Lepidocyclina pustulosa, L. macdonaldi, and L. chaperi Corals from Gatuncillo formation
are abundant and widespread. Discocyclinids (Astero- [Identifications by J. W. Wells]
cyclina and Pseudophragmina) were collected at 7 of the 15 localities, Helicolepidina spiralis at 6 localities, Localities
Fabiania cubensis at 6, Helicostegina soldadensis at Rio
only one. Yaberinella jamaicensis was found in the Madden Agua
basin Sucia
basal part of the formation (localities 1, la), associated o,
with Fabiania cubensis. Nummulites striatoreticulatus 8 11 12 16 2
is a relatively large nummulite for an American species. Operculinoides is extraordinarily abundant at locality Helioporasp ----------------------- X
10. Astrocoenia incrustans Duncan------According to Cole (1952 [1953], p. 4-5), the larger Aslreopora n. sp ........ .
Foraminifera of the Gatuncillo formation are dominated Diploastrea n. sp. aff. D. crassolamellata by species characteristic of the upper Eocene rocks of (Duncan)-------------------- -----Trinidad and Florida. He also pointed out that two of Goniopora aff. G. taberi Wells- X _--- -Porites (Synaraea) n. sp------------------the species (Yaberinella jamaicensis and Fabiania Favia cf. F. weisbordi Wells ----- -- -cubensis) are recorded only from the middle Eocene, Colpophyllia sp ----------..X
but that there are good grounds for considering that the Antillia cf. A. hadleyi Wells------ X
former ranges upward into upper Eocene in Jamaica and Millepora aff. M. alcicornis Linn6 ------ X
the latter into upper Eocene in Cuba.
Corals.-Corals are fairly common in limestone, for
the most part hard limestone that yields only random Wells reports that the new species of Diploastrea is
sections. Specimens that weathered out of softer marly closely allied to the widespread late Oligocene D. limestone and calcareous mudstone were collected at crassolamnellata and that the fossils from locality 11
five localities. Such fossils, which generally are poorly constitute the first record of a pre-Pleistocene alcicornispreserved, were found to be abundant only at locality like Millepora in America. He points out that most
11, where slabs of limestone from a partly demolished of the other species show close relationship to upper
hill are disintegrating. The collections were examined Eocene Cuban corals and a less marked relationship to by J. W. Wells, who identified the following species: middle Eocene corals from St. Bartholomew.

Mollusks from Gatuncillo formation (Nerilidae to Turritellidae)
Madden basin Rio Frijol Casaarea ya
6 7 9 11 12 16 32 34 3S

Velates perversus (Gmelin), subsp.? -- ------------------------------- >, X .. .
Hannatoma? ef. H. emendorferi Olsson---------------------------------------------------------Xenophora sp----------------------------------------------------
Hipponix sp--------------------------------------------------------------------------------------------Calyptraea cf. C. aperta (Solander)---------------------------------
Polinices? sp ---------------------------------------- --------------- -----------Neverita? sp--------------------------------------------------------Sinumii sp ----------------------------------------------------------------------------------------------Amaurellina? sp--------------------------------------------------------- ---------Pachycrommium? solenaeum Woodring, n. Sp --------------------------------------- -----------------------Turritella cf. T. carinata Lea--------------------------------------
cf. T. samanensis Olsson------------------------------------------- __ .
sp ----------------------------------------------------------------__ X ....


llu.ks.- A few microscopic mollusks were re- Foraminifera from the basal part of the formation are covered from forainiferal mudstone and siltstone. now available. The collection of mollusks from the Molds of mollusks weather out of limestones in Madden Rio Casaya area includes species of middle Eocene basin. The largest number of species represented by affinities, such as Turritella of. T. carinata, which are such molds was found at localities 11 and 12. Some- not represented in other collections. Stratigraphic what calcareous sandstone in the Rio Frijol area con- control, however, is completely lacking in the Rio tains a few species. The best preservation is shown by Casaya area. silicified fossils collected in the Rio (Casaya area (locality 38). These silicified fossils are casts composed of EOCENE OR OLIGOCENE SERIES
granular silica. They occur in partly silicified lime- MARINE MEMBER OF BOHIO(?) FORMATION
stone and therefore can be extracted by treatment with Marine strata of early Tertiary age in the Gatun Lake acid. area are tentatively designated the marine member of
The species listed on p. 21 are represented in the the Bohio(?) formation, pending further data on their families covered by Chapter A of the present report. stratigraphic relations. They are thought to represent
The mollusks of the Gatuncillo formation include a marine tongue, or tongues, in the lower part of the species of Tethyan affinities, an example of which is essentially nonmarine Bohio formation, which is deblatcs perverse. Hlannatomna is an American genus, scribed on pages 24-28. That interpretation, however, found in the Eocene of Peril, Colombia, and Venezuela, is a matter of inference. It is adopted principally and in lthe Oligocene of Peril. It is not certain, how- because in one of the outcrop areas the strata include ever, that Ilannatoma occurs in the Gatuncillo forma- rocks similar to those of the Bohio formation. tion, as the aperture and growth line of the species Whatever the stratigraphic relations of the unnamed identified as Ilannatoma? cf. H. emnendorferi is unknown. strata may be, a separate formation name may evenTurritella cf. T. carinata, and other species from the tually be preferred for them. As a matter of fact, a Rio Casaya area not included in the preceding list, in- name was casually used for them many years ago-a dicate a middle Eocene age, but the bulk of the fauna name incorrect in orthography and no longer suitable: suggests late Eocene. Vamos i1 Vamos beds or Vamos i Vamos formation
Echinoids.- Echinoids collected at locality 11 were (Hill, 1898, p. 179, 205).
identified by C. W. Cooke (1948)as Cubanaster' acusai, Though the thickness and extent of this unit are Wei.s bordclla dalli, IV. cubae, Schizasler armiger, and unknown, the thickness probably is at least 100 meters. Eupatagu.s ecblvi. Cubanaskr acuiai is very abundant
in slabs of silty limestone that are strewn about at STRATIGRAPHY AND LITHOLOGY
locality 11 (pl. 4). Incomplete remains of Eupatagus Vamos Vamos.-The unnamed marine strata were were seen at other places in the southern part of Mladden first observed near a now submerged village on Rio basin. According to Cooke, four of the five species at Chagres that had the intriguing name Vamos Vamos. locality 11 are found in the upper Eocene Ocala lime- The approximate position of the fossiliferous strata is stone of Florida, two in the upper Eocene of Cuba, and shown as locality 40 on plate 1. Though the name one in the middle Eocene of St. Bartholomew. Vamos Vamos suggests American slang, my colleague
Age.-Tlhe Gatuncillo formation is considered to be G. E. Lewis informs me that "vamos" is a colloquial of middle and late Eocene age. The faunal evidence equivalent of the more elegant "vimonos" and that consistently indicates that the greater part of the for- reiteration for emphasis is common in many languages. nation is late Eocene. Contrary to a former opinion The name appears on Garella's 1:200,000 map, prepared (Woodring and Thompson, 1949, p. 228), the formation, in 1844 and published in 1845 (Garella, 1845). Hill perhaps only a small part of it, evidently includes had his own hybrid version of the name: Vamos A middle Eocene, at least iiin Maddel(n basin and the Rio Vamos (Hill, 1898, p. 179), gallicized to Vamos a Vamos Casaya area. Yaberiella janaicensis was found in by MacDonald (1919, p. 542).
two collections at the very base of the formation, but The strata described as those at Vamos Vamos not, in other collections. Though that species occurs actually were exposed in a cut on the southwest side in both middle and upper Eocene in Jamaica, its ap- of the French Canal, about 2 kilometers northwest of parently more closely restricted range in Panamii the place where the canal joined Rio Chagres just upsuggests that the basal part of the Gatuncillo is middle stream from the village of Vamos Vamos. (See map, Eoceio. Unfortunately no other collections of larger pl. 1, accompanying publication cited under Bertrand and Ziircher, 1899.) These fossiliferous strata were
The eric nails for the first three species have bee, changed to e ith first mentioned by Chaper (1890, p. 7) and wee de)u1111 ns rieclass ic;l ion (Duriam, J. W., A new family of clyvpeastroid echioids: (189 1 ). we d J,,ir. 1'h: al, ogy, 2, p. 677 33titzs., 194). scribed by Hill (1898, p. 179-180), Howe (1907, p.


113; 1908, p. 219), and MacDonald (1919, p1). 542). Section of marine member of Bohio(?) formation on north coast of
According to these descriptions, the strata dipped Trinidad Island
toward the northwest and consisted of dark tuffaceous Siltstone, sandy. Locality 42c, 4.5 meters above base e__ 6 silty sandstone, containing practically black calcareous Sandstone, ledge-forming, silty, medium-grained, calcareous, concretions, and small-pebble conglomerate. Fossils containing few pebbles, few worn small heads of
were found in the calcareous concretions and also in the calcareous algae, and worn sheil tips of Turritella.
sandstone. MacDonald reported a thickness ol 95 Locality 42b--------------------------------- 1
feet (29 meters) at locality 40. Siltstone, sandy. Locality 42; locality 42a represents a
feet (29 meters) at locality 40. thin calcareous layer---------------------- 3
Hill thought the strata at Vamos Vamos to be
younger than the foraminiferal marl exposed farther Thickness of section ----------- 10
east (Hill, 1898, p. 179), and so did Bertrand and FOSILS AND .E
Ziircher (1899, p. 88). (The foraminiferal marl, now
submerged, is presumed to be part of the Caimito Larger Foraminifera.-No Foraminifera of any kind
formation.) Howe concluded that the coarse conglom- are in the collections from Vamos Vamnos and none
erate and volcanic breccia at Bohio, still farther east, were observed in the exposures near Palenquilla Point. and the strata of finer grain at Vamos Vamos represent The following larger Foramninifera were identified by different facies of the same formation: the Bohio formia- Cole in two collections from Trinidad Island: tion (Howe, 1908, p. 221). MacDonald and Vaughan
assigned the strata at Vamos Vamos to the Gatun Larger Foraminifera from marine member of Bohio(?) formation, formation (MacDonald, 1919, p. 542). Though Trinidad sand
little data on the structure and stratigraphy of the [Cole, 1952 (1953), p. 51
marine member of the Bohio(?) formation are now 42 42b
available, that unit seems to be exposed on an anticline, Operculinoides jacksonensis (Gravell and Hanna) -----. X as suggested on plate 1. kugleri Vaughan and Cole -------------------- X
trinitatensis (Nuttall) ----------------------Palenquilla Point.-When Mr. Thompson was re- Nummulites striatoreticulatus (L. Rutten)----------minded of the record of dark fossiliferous calcareous Fabiania cubensis (Cushman and Bermdidez)--------concretions at Vamos Vamos, he remembered that hlie Lepidocyclina (Pliolepidina) macdonaldi Cushman.... X
had seen such concretions near Palenquilla Point, (Pliolepidina) pustulosa H. Douvill ------------X >
which is close to the submerged Vamos Vamos locality. itedpustulosa tobleri 11. Douvill- ---------------. 1 itedby Cole as Carnerina.
Tuffaceous siltstone, tuffaceous medium- and coarsegrained sandstone, and lenses of conglomerate made up Cole pointed out that all the larger Foraminifera
of basaltic pebbles, cobbles, and boulders are exposed collected at Trinidad Island are found elsewhere in at scattered localities on the east side of the peninsula deposits of late Eocene age; in fact, all except two ending at Palenquilla Point. The coarse basaltic (Operculinoides kugleri and O. trinitatensis) are found in
fragments generally have a maximum diameter of 10 the Gatuncillo formation. Moreover two (Fabiana
centimeters, exceptionally 30 centimeters. Loose dark cubensis and Lepidocyclina pustulosa) occur in the fossiliferous calcareous concretions were found at the middle Eocene, but none in the early Oligocene. edge of Gatun Lake at locality 41 and in place in Mollusks.-A collection of mollusks from Vamos
medium-grained sandstone halfway between that lo- Vamos was forwarded to the U. S. National Museum
cality and Palenquilla Point. At other places medium- by Alexander Agassiz in 1891. Other collections were grained sandstone contains molds of mollusks. The made by Hill and by Vaughan and MacDonald. All
basaltic conglomerate suggests the Bohio formation. these collections presumably represent the same genWhether these marine strata will be found in an ex- eral locality. For some reason Hill sent in three lots
tensive area south and southwest of Palinquilla Point, that have different field numbers. Dall used specias suggested on plate 1, remains to be determined. mens from the Agassiz and Hill collections to describe
Trinidad Island.-The same stratigraphic unit forms four species he named Glyptostyla panamensis, iactra Trinidad Island. The following section is exposed on (Mactrella?) dariensis, Cardium (Fragum) gatue nse, the north coast of the island: and Pitaria (Lamnelliconcha) hilli in his monumental


Tertiary Fauna of Florida (Dall, 1890-1903, p. 233, tematic descriptions of chapter A of the present report. 895, 1100, 1268). The collections from localities 41a Species in the families covered by chapter A of the and 41b were received too late to be included in the sys- present report are tabulated below.

Mollusks from marine member of Bohio(?) formation (Phasianellidae to Turritellidae)

f Localities

Vamos Vamos Palenquila Point Trinidad

40 40a 40b 40d 40e 41 41a 41b 42 42c

Tricolia calypta Woodring, n. sp- ----------------------------------------- -- X
Calyptraca sp -------------------------x x
Natica (Natica?) sp------------------------------------------ _X---------X------------- X X
Tectonatica sp--------------------------------- --------- -- ----------- ---- X
Polinices? sp --------------------------------------------------------------------X -- --- X... ...
Neverita? sp------------------------------------------------------------------------------------------Neverita (Glossaulax) boliarensis tapina Woodring, n. subsp----------------- ...-X X X -Sinum sp ---------------------------------------------------------__-- X --- X ..
Globularia (Ampulella) sp ..--------------------------------------- X X X
(Ampulella?) nana Woodring, n. sp------------------------------------------------- -X -XPachycrommium? proinunm Woodring, n. sp -------------------------------------- I -- X > X
Turritella adela Woodring, n. sp ------------------------------------------x x ? x X
cf. T. caleta Olsson---------------------------------------------- X X X - -X

The mollusks of the marine member of the Bohio(?) and, above all, the absence of typical Eocene genera are formation are unlike those of the Gatuncillo formation. thought to outweigh the Eocene affinities and to indiTricolia calypta and the unnamed Tectonatica are the cate an early Oligocene age. That age, however, is earliest known American species of genera that appear not based on faunal similarity to the early Oligocene of in the Paleocene and Eocene, respectively, of Europe. western Europe or southeastern United States. The Neverita bolivarensis, tapina is a subspecies of a late most marked faunal similarity is with the late Eocene Eocene Colombian species. Pachycrommium? proi'um, of Colombia and the late Eocene and early Oligocene
the other globularines, and Turritella addela also have of Peril. Eocene affinities. Turritella cf. T. caleta appears to be Pending resolution of the apparently conflicting allied to the Oligocene Peruvian T. caleta. testimony of the larger Foraminifera and mollusks, a
Age.--In view of their stratigraphic range elsewhere, late Eocene or early Oligocene age is assigned to the the eight forms of larger Foraminifera point to a late marine member of the Bohio(?) formation. Eocene age (Cole, 1952 [1953], p. 5-6). Had these OLIGOCENE SERIES
fossils been found only in the sandstone that contains BORIO FORMATION
p)ebbles, worn small heads of calcareous algae, and worn The Bohio formation proper, excluding the doubtful shell tips of Turritella (locality 42b), the possibility of marine member just described, has fairly uniform reworking might be considered, despite the lack of any lithologic features. It is characterized by the preother evidence for reworking. Five of them, however, ponderance of poorly sorted debris, mostly basaltic: were found also in siltstone (locality 42). So far no very coarse debris in the form of boulders and cobbles, early O(ligocene fauna of larger Foraminifera in the and finer debris forming beds of sandstone, or more (aribbean region l'sS been described, although larger properly graywacke, and the matrix of conglomerate. 'Foramniifetra of that age quite certainly are represented The debris evidently came principally from the south in the While Liniestoneof Jamaica, in similar limestones and southwest. Boulder conglomerate is the dominant in Hl,it i ard the 1Doniican Republic, and in Cuba. type of rock in the Gatun Lake area, the southern part
1)all in fornied I ill that the NVamos Vamnos mnollusks of Madden basin, and the Pacific coastal area. In the are Foene ( lill, 18s98, p1). 271, 273). Some of the Quebrancha syncline conglomerate is replaced by grayspecies found there and( at th'e other localities have wacke grit. In the Gatun Lake area the formation Eoncele affinities, but others have later afflinities (Wood- apparently grades southeastward into agglomerate of ring and IThlomlpsoi, 1949. lp. 231). The latter allinit ies the Bas Obispo formation.


The poorly sorted conglomerate and the poorly for the French locks near the village of Bohio, mentioned
sorted graywacke contain no marine fossils and seem in early descriptions of the Bohio formation. to be nonmarine. Marine fossils are found in thin The poorly sorted coarse-grained matrix of the conunits in the upper part of the formation, in algal lime- glomerate and similar graywacke forming separate stone and in both poorly sorted and fairly well sorted beds is made up chiefly of angular grains of basalt in subgraywacke. If the tentatively designated marine a clay-like binder. On Barro Colorado Island carmember of the Bohio(?) formation is indeed the equiva- bonaceous debris is common in medium- to coarselent of the lower part of the Bohio, it represents a grained subgraywacke containing scattered pebbles, northwestward replacement of nonmarine conglomerate generally poorly rounded Marine fossils were found by marine sandstone, siltstone, and conglomerate, in such sandstone in the upper part of the formation on
Hill named the Bolio formation, but used the spelling Barro Colorado Island at locality 42g and 42i. They Bujio (Hill, 1898, p. 183). The name was derived also were found at locality 42d in medium-grained from Bohio or Bohlo Soldado, a village on the Panama subgraywacke that is better sorted and has little Railroad located on a bluff overlooking Rio Chagres carbonaceous debris. The fossiliferous sandstone at and now under the waters of Gatun Lake north of locality 42d contains somewhat calcareous irregular Barro Colorado Island. In Spanish orthography the lumps. name, anglicized in the Canal Zone, is Bohio. Though Though conglomerate and sandstone predominate, the little islands north of Barro Colorado Island are the formation includes tuffaceous siltstone. closer to the location of the village, the Bohio Peninsula The Bohio formation and Bas Obispo formation may be considered the type region. appear to intertongue. Both Hill and Howe described
In his description of outcrops Hill casually used agglomerate (volcanic breccia of their terminology) many names that have the form of formal stratigraphic exposed in a quarry at Bohio (Hill, 1898, p. 183; names. His expression "Bujio formation" evidently Howe, 1907, p. 112; Howe, 1908, p. 216-217), and Howe was intended to mean no more than "the formation at described subsurface evidence indicating equivalence of "Bujio." Four of his names-Bujio (Bohio) forma- agglomerate and conglomerate (1908, p. 217-218). tion, Culebra clays (altered to Culebra formation), According to Howe, between Darien and Gamboa a few Empire limestone (altered to Emperador limestone patches of conglomerate could be seen overlying agglommember of Culebra formation), and Panamd forma- crate before the flooding of Gatun Lake (1908, p. 215,
tion-bhave been preserved. "in the neighborhood of Mamei, Gorgona, and MataIn complete sections the Bohio formation overlies chin"). According to Jones, in the same region the Gatuncillo formation. So far as known the two conglomerate and sandstone of the Bohio formation formations are conformable, except in the Pacific grade into agglomerate of the Bas Obispo (1950, p. coastal area, where the Bohio overlaps the Gatuncillo 899-900). and rests on basement rocks. The thickness of the MacDonald (1913, p. 568) estimated the thickness
Bohio ranges from about 75 meters to perhaps as much of the Bohio in the Gatun Lake area to be almost 1,000 as 450 meters. feet (300 meters).
Quebrancha syncline.-The Bohio formation in the
STRATIGRAPHY AND LITHOLOGY Quebrancha syncline consists of a graywacke grit
member and an overlying volcanic member. Both
Gatun Lake area.-Boulder conglomerate is the most members have been described by Thompson (1944, p. characteristic rock type of the Bohio formation in the 13-17). The grit member is made up of poorly sorted Gatun Lake area. As shown on plate 5, the conglomer- coarse, angular grains and scattered pebbles of basalt ate is a rude assortment of boulders, cobbles, and and thin lenses of conglomerate, in which basalt prepebbles. Boulders predominate and reach a diameter dominates. The pebbles have an observed maximum of 2 meters. Basalt is by far the dominant rock in the diameter of 10 centimeters. In other words, the graycoarse constituents. In general the coarse constituents wacke grit closely resembles conglomerate in the Gatun are better rounded in the northwestern part of the Lake area, but has a much finer texture. Like the outcrop area, including Barro Colorado Island, where conglomerate, the grit appears to be nonmarine. Thin the view reproduced as plate 5 was taken. Conglomer- marine siltstone, however, was found in the basal part ate like that shown on plate 5 borders the launch chan- of the member. The maximum thickness of the memnel between the two small islands just northwest of the ber is estimated to be 450 meters. first peninsula on Barro Colorado Island west of Salud The volcanic member has a thickness of 30 meters. Point (Orchid Island and de Lesseps Island, not labelled It consists, in ascending order, of porphyritic basalt on plate 1). This channel is the site of the excavation (18 meters), agglomerate (9 meters), and greenish waxy


l(Ilntoltic clay (3 meterss. Sphleroidal exfoliated Sinaller Foramiinifera front basal part of graywacke grit member of mnasses, which weather out of the basalt and are very Bohio formation at locality 39 in Quebrancha syncline dural e, were found by Thlomipson to be useful gides [Idezitifications by H. H. Renz and P. J. Bermfidez]
inl mapping. This thin. volcanic inember evidently is Alabamina cf. A. scitula. Brady
a product, of the eruptions that produced thme Bas Ammnospirata mnexicana (Cushman)
OJbisp o format ion and thie Las Cascades agglomlerate. Angulogerina sp. Studv of the volcanic rocks may yield clues as to Astacolus nuttalli (Todd and Kniker)
whether thle volcanic mnemlber is the equivalent of part Bathysiphon eocenica Cushman and Hlanna of the iBas O)bispo or of part, of lte Las Cascadas. Bolivina alazanensis Cushman
iiadd n ba.Niu .-The JBohio formation has been byrantensis Cushman
recogniized only in the southeastern part of NMadden cf. 1B. gracilis Cushman and Applin
basi. Te oucro are inthebasi exendssouli- plicatella var. mecra Cushmnan and Ponton
basi. Te otcro ara i thebasn etend soth- rhontboidalis t'Millett) eastw ard a cross the continental dlivide and joinls the tectiformnis Cushman Pacific coastal area. As in the Pacific coastal area, SIp. the formation consists chiefly of poorly sorted massive Bulimina alazanensis Cushman con glo mera te. The estimated mnaximumi thickness is Chrsalogoni um aspea radCyma n tanot
200 meters. Thle absence of the IBohio in the northern lrsogniapeutChmnndSifrb part, of Madlden basin is attributed to overlap by the Cibicides mexicanus Nuttall Cainito forinla ion. perlucidiis Nuttall
Ptijic coastal area.-Jn thme P~acific coastal area the SPP.
Boho frmaionovelap th Gaunclloforiaton Glavulin oides cu bensis Cushman and Bermdidez
Bohi fomat on ver~i~stheGatucilo fomaton yclaniina cf. C. deform is Guppy and Iles directly on basemient rocks. The ]3oh'o Dentalina alazanensis (Nuttall) thins abruptly eastward. On thie west, side of Rio cf. D. maucron ata Neugeboren
Cabra, where the formation rests onl coarse-rained semilaevis Hantken (diorite, the thickness is not more than 75 meters. The p
outcrop in the western part of thec area is very wide Discorbis araucana (d'Orbignly) Of NUttall Epon ides umbonatus var. multisepta Koch
because the grade of the slope south of the continental Gaudryina (Pseudogaudryina) aiazanensis Chusman (divide Is almost, the samle, as the dip of the formation. Glandudina sp. Cuts along the TrainsistImniai Highway exp)ose massive Globigerina ciperoensis Bolli poorly sortedl conglomerate (1)1. 6) and poorly sorted ouachitaensis Howe and Wallace
graywacke. Basaltic debris predominates aln th imbln cbnisPle
highway, but the proportion of basalt decreases east- Guttulina byramensis (Cushman) ward.~( Thin~ lenses of algal limestone are nterbedded sp.
wi th cotnlerate in the upper part of the format ion at Gyroidinoides cf. G. girardana (Reuss)
locaitis 4345.At, locality 44 the limestone hans an Karreriella miexicana (Nuttall)
locaitie 48-AS.Lagena striata (d'Orbigny)
exposed thIiickness of (60 centinmet ers, the greatest Marginulinel pseudohlirsuta Nuttall ob~served thickne~ss. s imilis d'Orbigny
Nodogen erina cf. N. itavanen sis Cushmnan and Berm 6dez FOSSILS AND) AGE
The bulk of the JBohio formation evidlentlv is iioi- Nodosaria longiscata d'Orbigny Marine, as suggested by Howe (1907, p. 112-1 13) and mliliua Brnemann
Mfa()onadl (1915, 1). 20). Siiiidwoesrcre f. N. pyrula d'Orbigny
from the format ion lin the JBohio Pennisula (Berry, cf. N. soluta (Rleuss)
191,8,, 1). :12). Marine fossils, however, est ablish the sp. presence ol, marinle strialta, in at least, thle basal anid upper J\onion ef. N. gratcloupi (d'orbigny)
plits 4 le frl illt in.porntpilioides (Ficlitel and Moll)
i~t1~sof he ormt in.Osa nqularia mtexicana (Cole)
AS ~ ~ f IiqI -, Ior au 'T~ Snyslstoe tebal lan idaria sp.
J)art of' Ih e gravwnci ue grit mnu eu of thle Bohio ait Planuilina nuirialana Hiadley heA litv y19 ini th ie uehra ali a syn ci in e, yiceldC t he cf. P. ivac'llerstorji (Schwvager) folib l" WiI g s aler Fo ia mui iera, I((' d eI l d11 y IT. 11, Pl'ct ina nuttalli Cusunian and Stainforthi Heiiz an .'.Bl11dz I 'lectofron dicularia (1102(1nensis Cushmian~
alto *~.j~euluoez flIxicanfl (Cushmnan)
?o ugho ni Cushunian


Pleurostomella alterans Schwager localities (42d, 42i) and a mixture of marine, brackishbierigi Palmer and Bermddez water, and fresh-water mollusks at a third locality
cf. P. naranjoensis Cushman and Bermddez (locality 42f). Howe recorded the presence of marine
Pseudoglandulina conica (Neugeboren). Pseudoglandulina conica (Neugeboren) mollusks in carbonaceous sandstone penetrated in a
Pullenia of. P. quinqueloba (Reuss) core hole at the French lock site near Barro Colorado
Quinqueloculina cf. Q. maculata Galloway and Heminway Island (Howe, 1908, p. 220-221).
Robulus cf. R. alazanensis (Cushman) The fossils from Barro Colorado Islands, all of which
articulatus var. texanus (Cushman and Applin) occur in subgraywacke interbedded with conglomerate,
iotus (Cushman)
sp. were received too late to be included in the systematic
Schenckiella sp. descriptions of chapter A of the present report. The
Sigmomorphina cf. S. trinitatensis Cushman and Ozawa species in the families covered by chapter A are as
Siphonina tenuicarinata Cushman follows:
Siphonodosaria nuttalli var. gracillinma (Cushman and Jarvis)
sp. Mollusks from upper part of Bohio formation on Barro Colorado
Spiroloculine texana Cushman and Ellisor Island (Trochidae to Turritellidae)
Uvigerina of. U. adelinensis Palmer and Bermddez
chirana Cushman and Stone 424 42ft 42g
gardnerae var. nuttalliana Howe and Wallace Solariella n. sp., cf. S. depressa DalL ----------spinicostata Cushman and Jarvis Neritina sp---------------------------------sp. Hemisinus (Longiverena) n. sp., cf. II. atriformis
Vaginulina sp. Cooke__------------------------------------
Vaginulinopsis alazanensis (Nuttall) Crepidula? sp-------------------------------- >
Virgulina of. V. dibollensis Cushman and Applin Notica (Naticarius) sp------------------------
Vuloulina pachyheilus Hadley Polinices sp--------------------------------- x ?
Messrs. Renz and Bermdidez prepared the following Sinum sp---------------------------------- X
n t Ghbularia (Globularia) aff. G. fischeri (Dall) ..... X ? comments concerning these fossils: Pachycrommium aff. P. guppyi (Gabb)---------- X
The Foraminifera collected at locality 39 are of early Oligocene Turritella cf. T. altilira Conrad------ X .----------X
age. They have distinct affinities with the early Oligocene n. sp., aff. T. venezuelana Hodson ----------X
faunas of the Alazin formation (or Huasteca formation) of the In chapter B of the present report, it is proposed to Tampico region in Mexico (Nuttall, 1932), the Tinguaro forina- describe the new species in the preceding list and to describe the new species in the precedmng list and to tion (or Finca Adeline marl) of Cuba (Bermddez, 1950, p. 264-270), and Zone I in the lower part of the Cipero formation of redescribe the species identified as Globularia aff. G. Trinidad (Cushman and Stainforth, 1945). fischeri. The last species mentioned is abundant at
Larger Foraminifera.-The upper part of the Bohio locality 42d and is the same as that from the Caimito
on Barro Colorado Island yielded Heterostegina antillea, and Culebra formations described under the same name Archaias compressus, Lepidocyclina canellei, L. giraudi, on page 94. The fossils found on Barro Colorado L. waylandvaughani, L. vaughani, Miogypsina antillea, Island are of late Oligocene age.
and M. gunteri (Cole, 1957). Cole identified the follow- Age.-The basal part of the Bohio in the Quebrancha ing species, which were collected at localities 43 and 45 syncline contains smaller Foraminifera of early Oligoin the upper part of the formation in the Pacific Coastal cene age and the upper part of the formation in the area: Pacific coastal and Gatun Lake areas, respectively,
contains late Oligocene larger Foraminifera and molLarger Foraminifera from upper part of Bohio formation in Pacific lusks. Whether the formation represents so great a coastal area. time span in each of the areas where it crops out is
[Cole, 1952 (1953), p. 6] not known at present. It represents, however, more
43 45 than the early Oligocene age previously suggested Heterostegina antillea Cushman-------------------- X X (Woodring and Thompson, 1949, p. 228). That it does
Lepidocyclina (Lepidocyclina) parvula Cushman------ X --- not include all of the Oligocene is shown by the late
waylandvaughani Cole ---------------------- Oligocene age of the overlying Caimito formation.
yurnagunensis Cushman -------------------- x --- Oligocene age of the overlying Caimito formation.
yurnagunensis morganopsis Vaughan---------- X X The larger Foraminifera in the upper part of the
(Nephrolepidina) vaughani Cushman ------------ x Bohio formation of the Pacific coastal area represent
(Eulepidina) favosa Cushman------------------ X X the widespread Caribbean Eulepidina fauna. That
gigas Cushman------------------------------ x --- fauna and the Antiguan coral fauna that, accompanies it
Mollusks.-The upper part of the Bohio formation at many localities is traditionally assigned to the middle
in the Pacific coastal area yielded pectinids, but no Oligocene, because Vaughan correlated the Caribbean
other mollusks. On Barro Colorado Island the upper deposits with the Rupelian of northeastern Italy on the
part of the formation yielded marine mollusks at two basis of the corals and because he thought a middle


()ligocene assignment fitted the occurrence of these representation of the ('aimito as overlying the Emperafossils in soutliheastern United States (Vaughan, 1919a, dor limestone (now assigned member rank in the Culep. 199-203, 207). The iulepidina fauna is found in the bra formation) was based on misidentification of both Chickasaway limestone of Ala)bama, the Suwannee Emperador and Caimito (MacDonald, 1913, pl. 68). limestone of Florida, and the Flint River formation of In complete sections the Caimito formation overlies Georgia usage, and the Antiguan coral fauna in the the Bohio formation or volcanic rocks that are thought Flint River formation. These three formations are to include the equivalent of the Bohio. Though the now assigned to the upper Oligocene (Cooke, Gardner, actual contact has not been observed, it evidently and Woodring, 1943. chart; MacNeil, 1944, fig. 1; Cole, represents a discontinuity. In the northeastern part 1952 (1953), p. 6). A middle Oligocene age is not of the Gatun Lake area the Caimito seems to overlap unreasonable, if the American deposits that are essen- the Bohio and Gatuncillo formations, directly overlying tially thie equivalent of the European Aquitanian stage the basement complex, and in the northern part of are assigrne(d to the upper Oligocene. In the present Madden basin the Caimito overlaps the Bohio and rests report, however, they are referred to the lower Miocene. on the Gatuncillo. In the southeastern part of the The age range of the Eulepidina-Antiguan coral fauna Gatun Lake area the lower part of the Caimito (or percannot be assumed to b)e narrowly restricted(l. It is a haps the entire formation), appears to grade into the reef fauna and(l may eventually he found to have a con- Las Cascadas agglomerate. Wherever the Caimito sid(era)le time range, like the Lower Cretaceous Urgo- formation is dated it is of late Oligocene age, except in vian reef fauna. In the Canal Zone an(d Panamn,4 the Madden basin, where it includes both upper Oligocene Eulepidina fauna occurs in the upper part of the Bohio and lower Miocene deposits. The Caimito of that area formation and at one locality in the Caimito formation is described under the heading "Oligocene and Miocene (locality 51), and the closest approach to an Antiguan series." The Caimito of the Pacific coastal area, which coral fauna is in the Caimito formation (localities 52 is entirely of Oligocene age, appears to be continuous and 57). The time span between the deposition of the with the Oligocene part in Madden basin and is disupper part of the Bohio in the Pacific coastal area and cussed under the same heading. deposition of the Caimito at localities 51, 52, and 57 in According to estimates, the thickness of the Caimito the Gatun Lake area doubtless is not great, but it ranges from 250 to 400 meters. would be rash to correlate these deposits closely. STRATIGRAPHY AND LITHIOLOGY
CAIMITO FORMATION EXCLUSIVE OF MADDEN BASIN AND PACIFIC Gatun Lake area.-Three members of the Caimito COASTAL AREA formation were recognized by Jones in the Gatun Lake
The Gatuncillo and Bohio formations are widespread, area: lower, middle and upper (Jones, 1950, p. 900-901), but are fairly uniform lithologically despite their wide- which correspond, respectively, to the basal, lower, and spread distribution. The Caimito formation is the upper members of his former usage (Woodring and youngest widely distributed formation. It is, however, Thompson, 1949, p. 232-233). According to Jones, lithologically heterogeneous. Deposits in too many the lower member is made up of conglomerate and areas have perhaps been included in the Caimito, but tuffaceous sandstone. The conglomerate resembles within the type region the formation is heterogeneous. conglomerate of the underlying Bohio formation, but In all the areas where the formation is identified it is includes pebbles of tuff. The sandstone and the matrix marine, or at least mainly marine, and contains much of the conglomerate contain acidic tuff. The lower volcanic debris. member is correlated by Jones with the Las Cascadas
The name for the Caimito formation was proposed by agglomerate, but perhaps the entire formation is to be MacDonald (1913, p. 569). He did not properly define correlated with the Las Cascadas. The lower member the name then or later, and he specified no type region. of the Caimito is recognized only locally. Its absence In the absence of evidence to the contrary, it may be elsewhere may indicate discontinuity or lateral gradaassumed that the type region was intended to be the tion into deposits grouped with the middle member. region that furnished the name. Caimito, or Caimito The middle member consists chiefly of tuffaceous Junction, was located on the present alinement of the sandstone, some of which is calcareous, and lenticular Panama Railroad near Darien in the Gatun Lake area limestone, mostly algal limestone. Tuff, tuffaceous (Macl)onald, 1913, pl. 68). On the basis of accepting calcareous siltstone, and conglomerate are other conthe Darien region as the type region, the Caimito forma- stitutents. Agglomerate and poorly sorted, coarsetion consists of the strata, mostly tuffaceous, overlying grained, tuffaceous, nonmarine sandstone in the norththe Bohio formation. MacDonald included in the eastern part of Barro Colorado Island evidently are
Caimito formation strata now assigned to the La Boca the equivalent of marine strata in the middle member. marine member of the Panamni formation and his Foraminiferal soft limestone, such as that at locality


54f, doubtless corresponds to the foraminiferal marl of and the calcareous siltstone member. They have beeln publications issued before the flooding of Gatun Lake. mapped and described by Thompson (1944, p. 17 21). Foraminiferal marl was exposed at localities on Rio The economically important Quebrancha limestone Chagres, including Pefia Blanca, the type of locality member, which is quarried for the manufacture of of Lepidocyclina canellei. The approximate location cement, wats named by Thompson (1944, p. 17) is a of Pefia Blanca is shown as locality 55 on plate 1. separate formation. The type region is on the east Hill claimed that forainiferal marl could be seen to limb of the syncline and includes the quarry of the rest unconformably on conglomerate (of the Bohio Panama Cement Company. The Quebrancha member
formation) near Bohio (Hill, 1898, p. 178-179), but has a thickness of 110 to 135 meters. Subsurface Howe (1907, p. 113) was unable to recognize the explorations and outcrops reveal that it is made up, in
locality Hill described. The rhyolitic tuff on Rio ascending order, of three parts: calcareous siltstone and Chagres at Barbacoas, where the original line of the calcareous medium-grained sandstone, limestone and Panama Railroad crossed the river about 9 kilometers thin partings of calcareous siltstone, and somewhat west of Gamboa, presumably is to be included in the marly foramniiniferal limestone consisting for the most Caimito. The tuff was found to be so similar to tuff part of closely packed specimens of Lepidocclina. in the Panami formation that Hill (1898, p. 201), The foraminiferal limestone is by far the thickest part. Bertrand and Ziircher (1899, p. 91), and Howe (1907, The calcareous siltstone member, which gradationally p. 117) did not hesitate to correlate them. Though overlies the Quebrancha limestone member, includes no data are available on the comparative volcanic calcareous siltstone, tuffaceous pumice-bearing siltconstituents of the different formations, the correlation stone, and calcareous mnediunm-grained sandstone. This is not accepted (p. 41). Hill casually used the expres- member has an estimated thickness of 150 meters sion "Barbacoas formation" for the tuff and "San and is the youngest unit in the Quebrancha syneline.
Pablo phase of the Barbacoas formation" or "San Rio Chagres area.-The lowland along Rio Chagres
Pablo formation" for underlying rock he described as north-northeast of Gamboa probably is underlain by conglomerate of volcanic material (IHill, 1898, p. te Caimito formation, but only a small art of it
184-85, 87).the Calmito formation, but only a small part of it, 184-185, 187). southwest of Nuevo San Juan was examined. CalTuff agglomeratic tuff, tuffaceous siltstone, and Ne p an sea al
.. careous coarse-grained pebbly sandstone at locality 93 discontinuous sandy tuffaceous limestone are the and limestone and siltstone farther west contain principal constituents of the upper member, the thickest Foraminifera, including orbitoids identified in the field and most widespread part of the formation (Jones, a Dii incdi a dL i ni imte
1 as Lepidocyclina canellei and L. taughani. Limestone 1950, p. 901). exposed at and near Las Cruces before the flooding
The thickness of the Caimito in the Gatun Lake of Gatun Lake yielded a few mollusks (localities 94, 94a). area is estimated to be at least 300 meters and may be
considerably more. FOSSILS AND AGE
Rio Mlandinga area.-Along a tributary of Rio Man- Large Fora iifera.-Larger Foaiifera are wideLarger Ioranuinifera.-Larger Foraminifera are widedinga, west of the canal and south of Gamboa, the spread and locally abundant in the Caimito formation Caimito formation is characterized by a unit of con- of the areas just described, particularly in limestone oalomerate and conglomeratic sandstone that has a glomerate and conglomeratic sandstone that has a and calcareous siltstone. No fossils of any kind,
thickness of between 75 and 100 meters. Conglomerate however, are known in the lower member in te Gatun however, are known in the lower member in the Gatun
is not rare in the Caimito of other areas, but it consists Lake area and larger Foraminifera from one locality of thin scattered beds. The unusual thickness of are the only fossils available for the upper member in
conglomerate prompted Jones to propose the name that area. Douv il l recorded larger Foraminifera and
.that area. Dourille' recorded larger Foraminufera and "Caraba facies of the Caimito formation" (Jones, 7
"Caraba faces of the Caimito formation" (Jones, calcareous algae in collections from localities near Pefia 1950, p. 901). The conglomerate is overland by fos1950, p. 901). The conglomerate is overlain by fos- Blanca and Bohio Soldado, and expressed the opinion siliferous silty calcareous sandstone (localities 59 and that they are Oligocene (Douvi, 1891, p. 498, 499).
that they are Oligocene (Douvill&, 1891, p. 498, 499). 60) and limestone. Locality 61 represents coralliferous Later e identified the small orbitoid from Peia Blanca Later he identified the small orbitoid from Pefia Blanca limestone in this area.
h as Lepidocyclina and reaffirmed the Oligocene age
The distribution of the conglomerate is unknown. .ag
The istibuton f th coglomrat is nkn~m.(Douvill4, 1898, p. 598-599). This small species, one The extensive area farther west along the south border (Douvil, 1898, p. 598-599). This small species, one of Gatun Lake, shown on plate 1 as doubtfully underlain of the most common in the Caimito, was still later by the Caimito formation, has not been examined, named L. canellei for the collector, an engineer of the
Quebrancha syncline.-The Caimito formation of the first French company (Lemoine and R. Douvil16, Quebrancha syncline consists of two members: in 1904, p. 20). L. vaughani, another common species, is
ascending order, the Quebrancha limestone member extraordinarily abundant in the Quebrancha limestone


member. The type locality of L. vaughani is in the Foraminifera were submitted to W. S. Cole, who
type region of the Caimito formation on the Panama identified the species in the following table. Recently
Railroad near Darien: locality 49, which was referred Cole (1957, p. 314) also recorded 8 species from the to the Emperador limestone member of the Culebra Caimito of Barro Colorado Island, all except one of
formation by MacDonald and Vaughan (MacDonald, which occur in the Caimito elsewhere. The exception
1919, p. 539, locality 6021). Seven samples of larger is Archaias comnpressus, which is still living.

Larger Foraminifera from Cairnmito formation of Gatun Lake area, Rio Mandinga area, and Quebrancha syncline
[Cole, 1952 (1953), p. 7]


Rio QueGattm Lake area Man- brandinga cha
area syncline

No branUpper mem- cha
Middle member mem- bers limeber recog- stone
nized member

48 51 53 56a 5, 59 62a

Operculinoidecs panamensi (CusInm)n)-------------------------------------------------- --------
Ietcrosteina antillca Cuslman------------------------------------------------------- x x
isractlkyi (Gravell and Hnna ----------------------------------------------------------------- ---- --panamensis Gravell --------------------------------------------------------------- X--------- --------X

Lepidocyclina (lepidocyclina) asterodisca Nuttall ------------------------------------------ --------------------
(Lepidoryclina) cancllei Lemnoine and R. Douvill6 X------------------------------------ x x x
parvula Cushman --------------------------------------------------------------X X--------X
waylandvaughani Cole ------------------------------------------------------------------------------- X
yurnagunensis Cushluiman------------------------------------------------------- ---- ---- X -------?rnaflanensis mnorganopsis Vaughan--------------------------------------------------' ------------X

(Nephrolpidina) dartoni Vaughan ------------------------------------ X
tournovcri Lenioine and R. Douvill6--------------------------------------------------------------------vauqghani (Cuishnman ----------------------------------------------------------- _----- X
(Eulepidina) andoxa Cushman: -----------------------------------------------------
Miogypsina (liogypsina) antilla (Culshman)--------------------------------------------------- ---------------(Miolepidocyclina) panuamensis (Cushmnian)-----------------------------------------------------X- -----------All the species in the preceding table occur elsewhere formation (MacDonald, 1919, p. 540, 541). Four of the in deposits of late Oligocene age. Though the table seven species identified by Vaughan occur in the upper
does not include the calcareous siltstone member of the Oligocene Antigua formation of the island of Antigua Quebranclha syncline, Lepidocyclina canellei has been and one in the lower Miocene Anguilla formation of the recognized by R. II. Stewart in that meniber (Woodring island of Anguilla (Vaughan, 1919a, p. 208, 209). and Thompson, 1949, p. 234). Numerous specimens of a coral in limestone of the
Corals.-Macl)onald and Vaughan found corals in Cahnimito at locality 61 in the Rio Mandinga area is
the middle member of the Caimito formation of the identified by J. W. Wells as Gotiopora cf. G. cascadensis.
Gatuni Lake area at localities 52 (Geological Survey Alollusks.-Mollusks hav-e been found in the areas
6024b) and 57 (Geological Survey 6026). Locality 52 described in the preceding pages, but they are nowhere
was assigned to the Emperador limestone [member of abundant. The species covered in chapter A of the
the Culebra formation] and locality 57 to the Culebra l)resent report are as follows:


Mollusks from Caimito formation of Gatun Lake area, Rio in the Gatuni Lake area, the age of which is unknown,
Mandinga area, and Quebrancha syncline (Calyptracidae to is tentatively grouped \vith the middle and upper
Turritellidae) nileinbers as late Oligocene.

Rio Que- Tuffaceous strata in the Chorrera area, west of the Gatun Lake area diMan-ran- Canal Zone and south of Gatun Lake, are shown by a area n- separate pattern on the geologic map (pl. 1) in a region
-.- -- -of undifferentiated volcanic rocks. Though the unqNo named tuffaceous strata consist principallyv of tuffaceous Middle member ers lime- siltstone, tuffaceous sandstone, and tuff, they hiclude eod .tomn bentonitic clay, conglomerate, and agglomerate. Leaf nized menm--- -- ', -- ----,
her impl)rints are the only fossils that have been found. 56 57 57a 6o 62 The unnamed strata, which may be the equivalent of
part of the Caimito formation of the Gatun Lake area,
Trochit f. T. trochiformis (Born) are d(loubtfully referred to the late Oligocene.
Trochita cf. T. trochiformis (Born) ........ --- ----. ar
Netica (Noticarius?) sp-----------Sinum sp__-------------------------X ? ---- BAS OBISPO FORMATION AND LAS CASCADAS AGGLOMERATE
Globularia (Globularia) aff. G. fischeri The Oligocene formations so far described contain
(Dall)------------ -: \--------(Pachycrommium? ll)f. P- trinitotenis more or less volcanic material, mostly in the form of
Pachycrommium? of. P.? trinitaewn
(Mansfield) -------------------------- --- tuffaceous debris. The Bas Obispo formation and Las
Turritella meroensis Olsson "_ Cascadas agglomerate are entirely volcanic. They are
(Torcula) altilira Conrad, subsp- -- interpreted to represent pyroclastic rocks and minor S flows that accumulated at the periphery of a volcanic pile. The center of the pile evidently was west of the
Collections of mollusks from Barro Colorado Island Canal Zone south of the continental divide, 1nut and Pato Horqueto Island are not included in the sys- presumably is concealed by later flows. At all events tematic descriptions of chapter A of the present report. that region is characterized by thick volcanic rocks. (Pato Horqueto Island is one of the Brujas Islands Still farther out from the center of the volcanic pile the northwest of Barro Colorado Island.) The Barro Col- Bas Obispo formation and Las Cascadas agglomerate orado collections, which represent a moderate-depth are thought to grade, respectively, into the Bohio and facies, contain unidentified species of Solariella? (locality Cainito formations. 541), Calyptraea? (locality 54m), Natica (Natica?) The volcanic rocks now included in the Bas Obispo (locality 54k), Polinices (locality 54h and probably formation and Las Cascadas agglomerate were described localities 54j and 54k), and Neverita? (locality 54m). as massive igneous rocks )v Hill (1898, p. 189-191), Conglomerate on Pato Horqueto Island yielded mollusks and as "roche de Ganmboa" by Bertrand and Ziircher of shallow-water facies, including Calyptraea sp., (1899, p. 86). They were named the Obispo formation Sinum sp., Ampullinopsis spenceri, and Turritella sp. or Obispo l)receia by IHowe (1907, p. 110-111). The Ampullinopsis spenceri, a representative of a genus emendation to Bas Obispo formation and the splitting mainly of Oligocene age not found heretofore in the off of the younger part as the Las Cascadas agglomerate Canal Zone, is to be described in chapter B. were proposed by MacDonald (1913, p. 568). The
Echinoids.-Fragmentary remains of Clypeaster are type region of both formations is in the northern part fairly common in some areas. C. W. Cooke identified of Gaillard Cut, where they are the oldest exposed a complete specimen from locality 60 as C. concamvus. formations. Their thickness is unknown, but the
Age.-A late Oligocene age for the fossiliferous parts combined thickness is presumably several hundred of the Caimito in the areas described in the preceding meters. According to plate 1, near Gamboa the Las pages is indicated by larger Foraminifera, corals, and Cascadas agglomerate rests on the Bohio formation, the mollusks. Most of the mollusks just listed would not Gatuncillo formation, or the basement complex. be out of place in either upper Oligocene or lower Confirmation of this overlap is needed. Miocene deposits. Ampullinopsis spenceri [late Oligocene of Antigua, Puerto Rico(?), western Pan nim(?), STRATIGRAPHY AND LITHOLOGY
Ecuador(?), and Peru(?)] and Turritella meroensis The Bas Obispo formation and Las Cascadas agglom(late Oligocene of western Panam, Ecuador, and Perd) erate probably would ordinarily be combined as one however, indicate late Oligocene. The lower member formation. They differ, however, in induration and


therefore have different properties in excavations. STRATIGRAPHY AND LITHOLOGY
Both crop out in the northern part of Gaillard Cut and ladde a basi.-Five members are tentatively recogin the Gambloa area northwest of the cut. The Las nized in the Caimito formation of Madden basin. Cascadas a glonlerate extends farther west along the The only formal member names that are used are canmal than the Bas Obispo formation. To the south- those that have already been proposed, for detailed west both merge into undifferentiated and unmapped work may show that some arrangement other than vdalanic rocks. that "adopted in the present report is preferable. Two
According to Howe and MacDonald (in the publi- members are grouped as the lower part of the formation nations just cited) and( to accounts published by geolo- aind the upper three as the upper part. In the followists of the Geological Section of the Special Engineering ing paragraphs the members are described in upward I)ivision, both formations consist, principally of stratigraphic sequence. :aglonwerite and tuff. The matrix of agglomerate of The (calcareous sandstone-siltstone member overlies the l8s ()bispo is hard sandy tuff so firmly indurated the Bohio formation or overlaps it, and rests on the 1haui the rock breaks through the larger constituents. Gatuncillo formation. Sandstone of this member, ('rude peddling is apparent in local thin deposits of the ranging from very fine-grained to very coarse-grained Bas ()bispo made up of imperfectly rounded pebbles and conglomeratic, is well exposed on Rio Chilibrillo amd cobbles. Such rock is not as well indurated as the upstream and downstream from the bridge on the road agglomerate. The matrix of aggloimerate of the Las from Buenos Aires to Casa Larga. The sandstone ('ascndas consists of soft fine-grained altered tuff and is variably tuffaceous, and at least on Rio Chilibrillo betitonitic clay. Beds of tuff in the Las Cascadas the member includes massive coarse-grained tuff. also are softer than those of the Bas Obispo. Both The exposures oiln Rio Chilibrillo indicate a thickness of formations inchilde andesitic and dacitic flow breccias at least 200 meters. and hoth iare cu(lit by a few aundesitic (likes and by The pyroclastic-clay member includes agglomerate, lumerouis basaltic dikes, tuff, bentonitic clay, conglomerate, and limestone.
AGE Agglomerate may be seen on the Transisthmnian HighFossils have not been found in either the Bas Obispo way near Rio Chilibre on the east side of the basin.
or s Casdas. The are oubtfully referred to The strata on the east side of the basin also include o)r La s Cascadas. They are doub~tfully referred to
three lenses of limestone, two of which are exposed on the Oligocene l)ecause of their inferred relations to the ree lenses of limestone, two of which are exposed on
the Transisthmian Highway. The thickness of the
1oluo .and Caidnito formations (p. '25, 28). The Bas
member on the east side of the basin is about 110 meters.
()hispo and Las 'Cascadas presumably represent most te west side of the bsin, where the member is
of the Oligocene, not only early Oligocene as previously represented by steeply dipping clay immediately north represented by steeply dipping clay immediately north
suggestedt (H oodringo anid Tinompson, 1949, p). 228)...
suggested (Wooring l pson, 1949, 228). of Rio Chagres and just west of the Transisthmian
OLIGOCENE AND MIOCENE SERIES Highway, the thickness is probably not more than 50
The Chilibrillo limestone member- the lowest memiThe (iaimito formation of Mladden basin, unlike that her in the upper part of the formation--consists of of other areas, includes both upper Oligocene and lower lenticular limestone that has a maximum thickness of Miocene deposits. As shown on plate 1, in the northern about 30 meters. Detailed mapping may show that part of the basin the Bohio formation is overlapped limestone of that thickness lies at more than one by the (Caimito. The thickness of the Caimito in the horizon. The name Chilibrillo was casually used by basin appears to be about 450 meters. The deposits Olsson (1942, p. 234). The type region is on the east now referred to the Caimito formation were designated side of the basin near Rio Chilibrillo. Entrances to the Culebra formation, Emiperador limestone, Cai- caves in the limestone are located at locality 81, about nmito(?) formation, and Gatun(?) formation by Reeves 150 meters west of the Transisthmnian Highway, and an(d Ross (1930, p. 14 -17). nearby.
The strata in the Pacific coastal area assigned to the The calcareous sandstone member overlies the lower part of the Caimito appear to be a direct extension Chilibrillo limestone member, or in its absence overlies of that part in Madden basin. These strata in the the pyroclastic-clay member and in that event is at Pacific coastal area have an estimated thickness of not the base of the upper part of the formation. The more than 250 meters. most accessible exposures of the medium-grained


calcareous and tuffaceous sandstone are on the east observed in limestone of the pyro(lastic-clay member side of the basin along the Transisthmian Highway. in Madden basin. In fact, an Archaias-like species is
Highly calcareous sandstone is exposed at the north the only larger foraminifer noticed in limestone of that abutment of the Transisthmian Highway bridge across member. The species in the table that follows were Rio Chagres. The thickness of this member is about identified by Cole.
30 meters.
The Alhajuela sandstone member is confined to a Larger Foraminifera from lower part (if Caimnito formation of
small area in the central part of the basin at and near Madden basin and Pacific coastal area
Madden Dam. Before the construction of the dam the ICole, 1952 (1953), p. 71
village of Alhajuela was located on Rio Chagres oppo- .......... .. ...
site locality 85. (For location of Alhajuala see Reeves Localities
and Ross, 1930, pl. 5.) The massive fine- to coarsegrained tuffaceous sandstone forms the foundation of bai coa
Madden Dam and the gorge of Rio Chagres below the a
dam. Plate 7 is a view at the dam site. Fossil shells
are more conspicuous in this member than in any 64 67 69
other part of the Caimito formation in Madden basin.
The thickness of the Alhajuela is 85 meters. The Heterostegina antillea Cushman-------------- ---,, Lepidocyclina (Lepidocyclina) canellei Lename, in the form "Alajuela sandstones", was proposed Lepidocyclina (Lepidocylina) anei Lmoine and R. Douvill6 ----------------by Olsson (1942, p. 234, 243). The restricted usage parvula Cushman
suggested by his chart (Olsson, 1942, p. 234) is adopted yurnagunensis morganopsis Vaughan--- in the present report. (Nephrolepidina) vanghani Cushman- X
Pacific coastal area.-The lower part of the Caimito Miogypsina (Miogypsina) antillea Cashformation appears to extend continuously from Madden man-----------------------------------------basin to the Pacific coastal area. Agglomerate, tuffaceous sandstone, tuffaceous conglomeratic sandstone,
and conglomerate in the region between the basin and Alollusks.-Mollusks occur in the Caimito of Madden
the coastal area are thought to represent the lower part basin, but none was found in the Pacific coastal area. of the Caimito. The geology of this intermediate Limestone in the pyroclastic-clay member (localities
region, however, is complicated by numerous intrusive 71-73) and submerged calcareous strata of the lower stocks, and the succession of sedimentary strata and part of the Caimito (localities 65, 66) contain mollusks, their relations to those in adjoining areas have not been but none of the families covered by chapter A of the worked out. Limestone at locality 97, just east of present report is represented in the collections. The
Madden Highway, contains a small Lepidocyclina sug- typical form of Turritella altilira occurs in the Alhajuela gesting L. canellei on the basis of field identification. sandstone member at locality 89. Specimens of T.
In the Pacific coastal area the lower part of the altilira from the Alhajuela at localities 88 and 92, and Caimito is made up mainly of tuffaceous siltstone, from the underlying calcareous sandstone member at
tuffaceous sandstone, and conglomerate. Algal lime- localities 77 (T. cf. T. altilira) and 80, are not sufficiently stone, like that at localities 95 and 96, is a minor well preserved to determine whether they represent the constituent, typical form. Turritella gatunensist was found in the
FOSSILS AND AGE calcareous sandstone member (locality 82).
Smaller Foraminifera.-Smaller Foraminifera were Echinoids.-According to identifications by C. W.
found in the calcareous sandstone-siltstone member of Cooke, Clypeaster lanceolatus occurs in limestone of the Madden basin on Rio Chilibrillo: in silty very fine- pyroclastic-clay member (locality 71) and in subgrained sandstone at locality 68 and in sandy siltstone merged calcareous strata of the lower part of the at locality 70. These collections have not been Caimito (locality 66), and Clypeaster cf. C. pinarensis
identified. in the calcareous sandstone member (locality 84a).
Larger Foraminifera.--Lepidocyclina vaughaniis wide- Age.-The lower part of the Caimito formation in spread and abundant in the calcareous sandstone-silt- Madden basin, consisting of the calcareous sandstonestone member on the west side of Madden basin, ranges siltstone member and the pyroclastic-clay member, and throughout that member in the exposures on Rio the formation in the Pacific coastal area are considered
Chilibrillo, and occurs in the lower part of the formation of late Oligocene age, like the entire Caimito of other in the Pacific coastal area. Despite an apparently areas. The two species of larger Foraminifera from
favorable depositional environment, no orbitoids were the calcareous sandstone-siltstone member in Madden


basin and the five species from the Pacific coastal area perador limestone, presumably because of the possiare typical Caimito species and typical upper Oligocene bility of confusion with the Empire formation of species. The age of the pyroclastic-elay member of Oregon. Empire was the American name for a town Madden basin is b)ased(l principally on an early species near Culebra, whereas the French used the Spanish of Nodipecten found also in the middle member of the name Emperador for the same town. The town was Caimito in the Gatun Lake area. located on the pre-construction alinement of the
The upper part of the Caimito in Madden basin, Panama Railroad near Culebra, approximately at
cosisting of the Chilibrillo limestone member, the locality 117 as plotted on plate 2. The quarry near
locasitting as plotted onl plate 2. The quarry near
calcareous sandstone member, and the Alhajuela sand- Empire (locality 118 of plate 2), which is to be regarded stone member, is assigned to the early Miocene on the as the type locality of the Emperador limestone membasis of mollusks. The lower two members would be her, is overgrown and unrecognizable, and so is the referred to the late Oligocene by those who claim that similar limestone formerly exposed on a street in the Aquitanian and its essential American equivalents Empire. Limestone agreeing with descriptions of the are of late Oligocene age. The Alhajuela sandstone Emperador is still exposed along the canal. These member, however, is late early Miocene; that is, beds of relatively pure coralliferous limestone probably
younger than the disputet ed ()ligocene or Miocene. are at different horizons in the upper part of the Culebra That it may include early middle Miocene. as suggested formation and probably grade southeastward into in a preliminary account (Woodrinig anid Thompson, calcareous sandstone (Woodring and Thompson, 1949, 1949, p. 236), appears to b)e unlikely. p. 237). Should it be demonstrated that the name is
Only the Oligocene part of the Caimito is recognized being used for limestone at different horizons, the name in the Pacific coastal area. It is overlain and perhaps should be abandoned, except for the limestone at the partly overlapped by the Panamii formation, which is type locality. In that event, however, a formal name correlated with the lower part of the Miocene strata would hardly be needed for a single locality, even if the in the Caimito of Madden basin. No fossiliferous locality were again found. In the meantime no serious
strata as young as the Alhajuela sandstone member errors should result from usage of the name. The have so far been found in the Pacific coastal or Gaillard coralliferous limestone has a maximum thickness of 15 Cut areas. meters. It therefore is a minor constituent and is
MIOCE'NE SERIES giVli mem0111ber rank in the Culebra formation.
CULEBRA FORMATION. INCLUDING EMPERADOR LIMESTONE MEMBER The Emnperador limestone member of the Culebra fformation is known to occur only in the northern part
The Culebra formation is recognized along and near of t outcrop area of the Culebra. MacDonald's
.n .)f the ouitcrop area of the Culebra. MfacDonald's tihe canil in the (Onillard (C'ut area and immediately to
he sont.east i. the reg string Pedr Iigel representation of the Emperador as widespread and th1e souitheast Inl thle reon straddliwr, Pedro Mliguel.
ocks. (For large-scale map of the (aillar Ct resting unconformably on formations of different age Locks. (For a large-scale map of the Gaillard Cuit .5
was based on misidentification of limestone in several
aren see plate 2.) To the southwest presumIably it
formations (MacDonald, 1913, pl. 68). According to
merges into undifer(,reniitiated and unmiapped volcanic t present interpretations, coralliferous limestone in the
roc(ks, like other formations in the Gaillardl (ut area., La Boca marine member of the Panama formation on
fboll CElebra itself conitainls volcanic debris, but nt
The (ula iself contains volai ebris, t not Rio Masambi, in the Gaillard Cut area, was recently
nearly So much as the 11underlyin1 and tle overlying
.nmatios. uh a o the rigantm ovin e misidentified as Emperador (Woodring and Thompson,
formations. i in11e for the forition, 1i1 the form 1
"(Olebra clays," was iirsl used by Hill (1898, p. 192- 1949, 1 27). 195). IThe type region i in tle central (aillard (ut STRATIGRAPHY AND LITHOLO(GY
are, where the town of Culebra was located on tlie Stratigraphic sections of the Culebra formation in
west side of tlie canal before aid during the construc- (Gaillard Cut have been published by MacDonald (1919, ion period. The Culebra formation uniconformiably ). 535-539) and he also published structure sections (verlies the Las (asca(las aigglomerate. The maximum of part of the cut (Natl. Acad. Sci., 1924 figs. 4, 5, op. thick ess of the formation is about 150 meters. The p). 52). Ie divided the Culebra into lower and upper tIhickness decreiases norlihward, evidently as a result, of parts. The lower part consists chiefly of dark-colored, overlap) of sulinssively younger parts of the formation thin-1)edded or laminated, fine-grained rocks: carbonaonl thle as Cas'adas agglontierate. ('eous or lignitic shale, carbonaccous silty mudstone,
Coralliferous limestone expose(l in a quarry near tuffaceous siltstone. It includes, however, minor beds Empire aIttratedI attention at an early date and was of tuffaceous and calcareous sandstone and conglomermmied thle Empire limestone by Iill (1898, p1). 195 -196). ate. The upper part is characterized by calcareous IlacD)onald (1913, p. 569) changed the name to Em- anid sandy strata ranging in thickness from 0.3 to 3.5


meters and in composition from tuffaceous and pebbly Section of upper part of C blbra formation, including transition
calcareous sandstone to sandy limestone. The cal- zone between Culebra and Cacaracha formations, on wu st side
of Gai/lard Cut aIt canal statIOn 1759) near site of Caub bra-careous and sandy strata are separated by dark cal- of Gaillard Cut at canal sttio 1759 near si of br~Continued
careous or somewhat carbonaceous shale and mudstone. C ut's
Carbonaceous strata in both parts of the formation 5. Sandstone, light-gray, nidium- to coarsegrained, poorly sorted, calcareous; siltstone
contain land plant debris, including identifiable leaves partings -------------------------------- 2
(Berry, 1918). -1. Shale, dark to black, caleareous, so newhat
Generally the Culebra formation is overlain directly carbonaceous ---------------------------- 1. 4
Generally3. Sandstone, light-gray, inediurn- to coarseby conglomerate at the base of the Cucaracha forma- Sandstone, light-g di- to Crsgrained, poorly sorted, calcareous, in beds
tion, marking a discontinuity, evidently a minor dis- 30 to 90 cim thick and interbedded with
continuity. On both sides of Gaillard Cut, however, poorly exposed somewhat carbonaceous shale.
just northeast of the site of Culebra, somewhat cal- Includes a 15-cm layer of conglomerate -- I
careous silty sandstone and sandy siltstone interbedded 2. Sandstone, coarse-grained to conglomeratic.
with clay like that of the Cucaracha form a transition calcareous; contains a moderately large
smooth species of oyster. 5------------------zone between the two formations. The transition zone 1. Sandstone, light-gray fine- to medium-grained,
is included in the Culebra formation. Sluicing opera- poorly sorted, calcareous, in beds 30 cm
tions carried on in 1947 on the west side of the canal, thick and interbedded with dark to black
in the region where the transition zone is represented, calcareous and carbonaceous shale and mudexposed the section below. Unit 1 is at the level of the stone. Locality 108, 1.5 in above ege of
canal -----------------------------------4. 2
Thickness of section ------------------33. 5
Part of the transition zone is exposed on the east sidle Section of upper part of Culebra formation, including transition Part of the transition zone is exposed o the east sie
zone between Culebra and Cucaracha formations, on west side of the canal at canal station 1754. Fossiliferous strata of Gaillard Cut at canal station 1759 2 near site of Culebra corresponding to the fossiliferous parts of bed 13 of the preceding section are recognizable on the east, Transition zone between Culebra and Cucaracha forma- n r
tions: Meters side, but the best-preserved fossils are weathered out
15. Clay, dark-gray, slickensided, and silty carbona- and were put in one collection (locality 110). Silicified
ceous clay. Overlain by light-gray medium- wood is common at that locality, including segments of
grained locally conglomeratic sandstone taken logs riddled with shipworm tubes (Teredo).
as base of Cucaracha formation ------------ 4. 6 Limestone of Emperador type in the upper part of
14. Siltstone, limonitic-weathering, dark-gray; few
gypsiferous shell tips of Turritella weathered the Culebra crops out farther northwest on the west out --------------- 9 side of the canal on both limbs of a syncline near the
13. Siltstone, dark-gray, sandy; includes a 15-cm site of Las Cascadas. At locality 120 (canal station
fossiliferous somewhat calcareous layer at 1600) the limestone is 6 meters thick and in a nearby
base (locality 112) and fossiliferous calcare- core hole is 24.3 meters above the base of the Culebra.
ous concretions at and within 30 cm of top
(locality 112a) 1. O At locality 121 (canal station 1619, pl. 8) the thickess
12. Clay, greenish-brown, slickensided, silty .------- 5 is 15.2 meters and the limestone is about 27.3 meters
11. Sandstone, greenish-gray, silty, medium-grained; above the base of the Culebra. At both localities the
and siltstone -----------------------------1. 6 underlying strata consist of dark carbonaceous clay and
10. Sandstone, brown ish-grayv silty, medium10. Sandstone, brownish-gray, silty, medium- tuffaceous siltstone. The basal 30 to 60 centimeters of
grained; and siltstone containing petrified
wood -----------------------------------1. 1 the limestone at locality 120 is silty and contains
9. Clay, liimonitic-weathering, slickensided, dark- numerous pectinids. The limestone at locality 121 ingray ------------------------------------1. 3 cludes a basal calcareous siltstone bed that has a thick8. Clay, grayish-green, somewhat carbonaceous ness of 15 to 30 centimeters and a middle calcareous
and somewhat fissile ----------------------2. 3 siltstone bed 2.4 meters thick. The limestone at
Culebra formation proper, upper part:
7. Sandstone, light-gray, medium-grained, poorly these two localities appears to represent the same zone
sorted, silty, calcareous; siltstone partings__ 1. 5 and probably is the same as limestone near Tower N,
6. Shale, dark-gray, silty, somewhat carbonaceous; a signal tower on the pre-construction line of the Panincludes thin layers of calcareous sandy silt- ama Railroad near Las Cascadas. Fossils from "the
stone -----------------------------------1. 3 Pecten bed" near Tower N were recorded by Brown and
2 The canal stations are located at intervals of 100 feet (30 meters) along the center Pilsbry (1913, p. 502-503). The limestone in the Las alinement and are numbered from the Caribbean terminus to the Pacific terminus. Strictly speakingthe rock exposures areopposite the stations, notatthem. Cascadas area is presumed to be the equivalent of


cnl(careous sandst one in tlhe measured section at canal (locality 100) are in'theCulebra formation. A1iostation 1759. MacDonald (1919, p. 537) assigned to gypsina intermedia is recorded from the Culebra at the Eminperador "somewhat sandy limestone" at locality locality 115 near Paraiso (Drooger, 1952, p. 36). 99g (canal station 1606). The matrix of the numerous Corals.-Of the four species of corals recorded by fossils MacDonald collected at that locality consists Vaughan from the Culebra formation proper, one occurs of sandy limestone that does not resemble the Emper- in the Emperador limestone member, three in the ador limestone. Antigua formation, and all in the Anguilla formation
FOSSILS AND AGE (Vaughan, 1919a, p. 208; Geological Survey locality
Smaller IOramniifera.-A few species of smaller For- 6026 represents the Caimito formation). Vaughan aminifera from the Culebra formation were recorded listed 24 species of corals from the Emperador limestone by Cushman (1918). Some of the localities referred to member. Four of them occur in the Antigua formation the Culebra in Cushman's publication represent other and nine in the Anguilla formation (Vaughan, 1919a, formations: Geological Survey localities 6009 and 6010 p. 209; Geological Survey locality 6024b represents the represent the La Boca marine member of the Panama Caimito formation and 6256 the La Boca marine memformation; localities 6024a, 6025, and 6026 the Caimito ber of the Panama formation). formation. Though the fauna of the Culebra is not 2follusks.-MacDonald made numerous collections
extensive, more species than the few recorded by Cush- of mollusks from the Culebra formation during the man are represented in core collections obtained during excavation of Gaillard Cut. Much of the material, the operations of the Geological Section of the Special however, is poorly preserved. Except in the Paraiso Engineering Division. Meager collections can still be area, the Culebra fauna includes species indicating obtained at outcrop localities, such as localities 104 and brackish water, particularly in the transition zone 108. It has been claimed that Siphogenerina trans- between the Culebra and Cucaracha formations (localirrsa, is not found in the Culebra formation (Woodring ties 110 to 112a). The Neritina, for example, indicates and Thompson, 1949, p. 241). M. N. Bramlette, brackish water and Littorina angulifera is a modern however, identified a small specimen of that species species that lives in mangrove swamps. Most of the in core material from a depth of 88 feet (26.7 meters) species indicating brackish water are absent in the in core hole SL108 and another small specimen from Paraiso area (localities 113 to 116). Plate 2 indicates a depth of 133 feet (40.4 meters) in the same core hole. that the fossiliferous strata in the Paraiso area are Core hole S1i08 was located 1.1 kilometers west- close to the top of the Culebra. It has been suggested
southwest of locality 101 and evidently the Culebra that the uppermost part of the formation in the Paraiso formation was penetrated at the depths just specified. area is the equivalent of the transition zone but repreLarger Foraminife'ra.-Cushman i's identifications of sents an environment farther seaward (Woodring and the species of Lepidocyclina in the Culebra formation Thompson, 1949, p. 239). According to the evoluhave not been confirmed(Cushman, 1918a,p.90). H.G. tionary scheme worked out by Drooger for mioSchenck identified Lepidocyclina canellei in core samples gypsinids, however, liogypsina intermedia, which at horizons 30 to 45 meters below the top of the Culebra
(Woodring and Thompson, 1949, p. 238). Cole occurs in the Paraiso area, is less advanced than 2M. (Woodring and Thompson, 1949, p. 238). Cole..
reenlydecr.e adiusre .ialrni cushmans, found mn the upper part of the Culebra
(locality b99g) and L. wayla aughani (locality 99a) farther northwest (locality 107), where the transition (locality 99g) and L. waylandeanghani (locality 99a)
from the Culebra formation proper, and L. mirajlorensis zone is not known to be present (Drooger, 1952, fig. 17, (locality 119a) from the Emperador limestone member p. 72). (Cole, 1953a). The type localities of Mliogypsina The following mollusks are in the families covered by
cushmani (locality 107) and "Orbitolites" americana chapter A of the present report:


Mollusks from Culebra formation, exclusive of Emperador limestone member (Neritidae to Turritellidae)

98 99a 99b 99C 99d 99f 99g 99h 100 100b 104b 106 107 1001 108c 110 110a 11 1ll1b 112 112a 114 115a 115: 116

Neritina (Vitta.) sp --------------- --------- ------.------------------ X -Littorina aff. L. angulifera
(Lamarck)------------------... . . ... .. .. .----
Rissoina (Zebinella?) sp --------------- I X ......- ........... .....
Xenophora sp------ .... .-- --
Hipponix? sp ...-----------------
Crepidula sp --- -Calyptraea of. C. centralis I -
(Conrad) - X X --Trochita? ef T. trochiformis
(Born) .. ro... f. ..------------ ..----------- --- --Crucibulum sp------------- -----X----. --- --- ------ ---------- ---.
Natica (Naticarius?) sp --- -----Polinices? sp -----------X------- . X X X -- -- ---Neverita? sp -- -- / _-- -- -- ---- -------- X
Sinum sp---------------------- 1'7 <
Globularia (Globularia) aff. G.
fischeri (D all) - - - - - -
Pachycrommiumn? ef. P.? trinitatesis(ansfieldy.---------------------- --- ---<------IK
tatensis (Mansfield) ---of. P. guppyi (Gabb)---------- .
Turritella (Torcula?) amaras
Woodring, n. sp------------- X X ..--- --------------- < < K < -i....X
sp ----------------------- --- --- --- --- ---< ef. T. berjadinensis cocoditana Hodson------------------- ....---------
--- -------r------ -Collections from the type locality of the Emperador Colombia, were available for comparison. This material indimember contain only a few species of mollusks, none cates that the metapodial from the Canal Zone may represent a of which represents the families described in chap ter A South American leontiniid or a North American rhinocerotid. of the present report. Limestone in the Las Cascadas Despite a search in 1947 and 1949, no additional
area assigned to the Emperador contains Neverita? sp. mammal remains were found at or near locality 110 (localities 119a, 120) and Turritella altilira in the un- Age.-Douvill (1891, p. 499) and Hill (1898, p. 195), restricted sense (locality 120). relying entirely on lithologic similarity to lignitic strata
Echinoids.-Olypeaster lanceolatus and Echinolampas in the Eocene of the Gulf states, suggested that the semiorbis were recorded from the Emperador limestone Culebra is Eocene. A review of other age assignmember by Jackson (1917, p. 490, 498). ments-Eocene, Oligocene, Miocene-would hardly be
Aflannal.-In 1942 T. F. Thompson found an in- profitable. It may be pointed out, however, that
complete mammal bone in the transition zone between Douvill4 (1898, p. 591) and Bertrand and Ziircher the Culebra and Cucaracha formations at locality 110 (1899, p. 89, 90), evidently following his advice, thought on the east side of the canal-the first Tertiary mam- that small orbitoids in strata that presumably represent mal to be found in PanamA. The following comments the Culebra are reworked.
on this fossil and the drawings by O. J. Poe reproduced The fossils of the Culebra formation, including the as figure 2 are available through the kindness of R. A. Emperador member, have both Oligocene and Miocene Stirton, of the University of California. affinities. The orbitoids (three lepidocycline species of
The bone found by Mr. Thompson is the distal part (length Lepidocyclina) point to Oligocene. In fact, some pale78 millimeters) of a metapodial of an ungulate of medium size. ontologists consider lepidocycline species to be decisive It was examined by H. E. Wood, 2nd, who thought it represents for an age not younger than late Oligocene. According a rhinoceros similar to Diceratherium. G. G. Simpson doubted to Vaughan's data, the corals favor correlation with the that it is a South American ungulate, but had no material for Anuilla formation of Angilla, which contains no close comparison with the leontiniids. The apparent rhinoceros A affinities seemed to be conclusive until late Miocene leontiniid orbitoids. The mollusks also favor correlation with foot bones, collected by University of California expeditions in the Anguilla and other formations of the same age,






Nil. Calif. Mn.PaleontolIg1 37l3, natora MM.
1!i.'4r10nt vjww
,Posterior %jew
h~inititg tm e radinpn Ihnvs nst0e of Florida, whITh also of the hlarger (piest ion of whlet her t he AquitanIian~ stage cont ains no orbitoids. Xone of t he mollusks i the of western ]Europe is late Oligocene or carly -Miocene, preceding list, suggest, species that tare only of greater for the Culebra and correlated formations are the essenage thIiani dispul1ted Oligocene or J\I oene, whereas Lit- ti al equivalent of the Aquitanian It has long been. lonot W L. uiytilift ra, IPach ?/~lmrIiumin? Af 1. gul Ipy, 'eognized that the inarine type Aquitanian of the and I erie/l cf. I. snhfgrund'lfua suggest species t hat Aquitane busiti cntains an early M\iocene fauna. The nrv M of younger age than dispu~dt ed (Higocene or urgumuenit couwnn the age of the, Aquitamnan. centers MIicetie. Vdtet I er the (1ulehrat format ion is to be on the Oligocene aspect of the nm-ninalian fauna in atssign ed to te hite 01ligocene or early '\ Ia te t is part noninarine strut a that are thought to be the equivalent


of the marine type Aquitanian. An early M\iocene age 52). Later, however, it was found to be ani aglamfor the Culebra formation agrees with the age assign- eratic tuff (MacDonahld, 1947, p. 9-10; Tliomip)soi, ment adopted by the Geological Survey for the Tampa 1947a, p. 16). Hand spec'nimens show fehispar crystals. limestone. That assignment for the Culebra, includ- flattened little lentils of dark clay, and greenis aigular ing the Emperador member, is adopted for the present rock fragments. During the investigations of the report, instead of the late Oligocene(?) and early Mio- Geological Section of the Special Engineering Division cene age assignment recently used (Woodring and this bed of tuff was known as the ash flow. Description
Thompson, 1949, p. 239). of thin sections of the tutf ald a chemical analysis are
presented on pages 54, 55. Chemical analyses of six
CUCARACHA FORMATION samples of (clay from the Cucaracha were published inII
The Cucaracha formation crops out alontig and near the NationalAcademyofSciencesreport oi lides(Nat.
the canal in the Gaillard Cut area an(l southeastward Acad. Sci., 1924, p. 54) and were reproduced by Marto Miraflores Lake. Its distribution is much like that Donald (1947, p. 10). Both reports just cited also, of the underlying Culebra formation, but it is recog- include descriptions of microscopic and other featnre< nized at a greater distance from the canal than tihe of the clay (Natl. Acad. Sri., 1924, p. 54-66; MacCulebra. The name was proposed by MacDonald Donald, 1947, p. 12-19, 65-70). No mineralogical
(1913, p. 569). Up to that time the strata constituting study of the clay by modern techniiiques has been the Cucaracha formation had been included in the undertaken.
Culebra. The type region is in the southern Gaillard FOsSILS ^X D ;:
Cut area. The site of the village of Cucaracha was on The absence of marine fossils and the presence of the east side of the canal between the continental di- plant debris in carbonaceous clay suggest that thie bulk vide and Paraiso. The maximum thickness of the of the Cucaraceha formation is nonmarine. The only
formation is about 190 meters. The discontinuity at plant remains recorded consist of wood (Berry, 1918). the base of the Cucaracha generally is sharp and Afew marine and brackish-water fossils have been found
marked by conglomerate, but in central Gaillard Cut in the lower part of the formation: Anadara and Crasa transition zone lies between the two formations. sostrea in conglomerate and poorly preserved molds and (See p. 35.) impressions of Anadara, Lucina?, and Tellina? in earSTRATICRAPHY AND LITHOLO(Y l)onaceous clay (locality 122). The collection from
locality 122 is the only collection now available.
The Cucaracha formation is the most distinctive and In N november, 1956, II. Stewart found the ist
the most uniform formation in the Canal Zone. It was end of a femur in tie Cucaracha formation, about t10 involved in the extensive slides in Gaillard Cut during meters above the top of the welded tuff, at Contractors excavation of the cut and during a period of several Hill, in the Gaillard Cut area at the continental divide. years after the canal was opened. Its physical proper- It was examined by R. A. Stirton, of the University of ties were exhaustively investigated during the studies California, who reports (in a personal communication) of the Third Locks project, carried out by the Special that it may represent a North American rhinocerotid Engineering Division. or a South American notoungulate. In other words,
The principal constituent of the formation is massive the uncertainty is the same as that for the metapodial generally grayish yellow green waxy highly slickensided from the transition zone betl teen the Culebra and bentonitic clay. Carbonaceous and lignitic clay, clayey Cucaracha formations (p. 37). siltstone containing yellowish gray calcareous concre- The few fossils found thus far furnish no reliable tions, tuffaceous clayey sandstone, and small-pebble evidence concerning the age of the Cucaracha. It is conglomerate that has a tuffaceous matrix are minor assigned to the early Miocene because both tile underconstituents (Thompson, 1947a. p. 16-17). A bed of in Culebra formation and the overlying Pananni
lyng Culebra formation an leoveilvi( ainz
dacitic welded tuff is a useful and exact datunm plane. formation are considered to be of that age. Its thickness ranges from 0.3 to 10 meters. In the
base of the formation and 60 meters below the top
(MacDonald, 1947, p. 9; Thompson, 1947a, p. 17). It The Pananma formation is tihe youngest Tertiary is the only hard rock in the formation and looks much formation in the Gaillard Cut and Pacific coastal areas. like a lava flow. In fact, it was described as a sill by It crops out in scattered areas in the central and southHowe (1908, p. 231), as a flow by MacDonald (1913, ern Gaillard Cut area and more extensively farther p. 569), and was shown as a flow in MacDonald's struc- southeast and east. It consists mostly of volcanic rocks, ture sections (Natl. Acad. Sci., 1924, figs. 4, 5, op. p. the youngest volcanic rocks in the Canal Zone. To the


west it grades into undifferentiated volcanic rocks and racha formation are shown by subsurface sections. The west of thie border of plate 1 volcanism continued much town of La Boca, which furnished the name, was located later, near the entrance to Balboa Harbor, but was abandoned
The marine strata constituting the La Boca marine in 1954. Though the La Boca member overlies the member and the agglomerate making up the Pedro Cucaracha formation, the lower part of the La Boca
Miguel agglomerate member interfinger with each other evidently is the southward marine equivalent of the and with the lower part of the tuff and generally fine- upper part of the Cucaracha formation in the area of gained agglomerate forming the Panama formation maximum thickness of that formation. The maximum proper. All three were formerly given formation rank thickness of the La Boca member is about 185 meters. (Thompson, 1947a, p. 18-19, 20; WoodrinEr and Thomp- Along and near the canal the La Boca member is son, 1949. p. 241-242). For the time being, however, represented principally by mudstone in both outcrop member rank appears to b)e preferable for the La Boca and subsurface sections. The mudstone is similar to andml the Pedro Miguel. that in the Culebra formation, but may be distinguished
The Panai formation was nae by Hill (1898, by the lower content of carl)olnaceous matter and the
nic Panama4 formation was named by Hill (1898, 1).
200-202). That the name was casual is indicated by richer foramniniferal fauna of the La Boca. Locality Ie expression "so-called Panama formation" ol page 124, on the east side of the canal at canal station 1702,
theexlresionso-called Panama formation" onpage
20( in his publication. The formation was named for is the northernmost locality where such mudstone is exposures along the water front in the city of Panami, now known to crop out along the canal. Core drilling, which is considered the type area. The names La Boca hliowever, penetrated the La Boca farther north in a formation and Pedro Miguel agglomerate were proposed syncline on the west side of the canal. hy Thompson (1943, p. 16-18). The Miraflores Locks Mudstone of the La Boca exposed in the canal excaarea has been designated the type region of the La Boca nation between Paraiso and Pedro Miguel Locks utnrin m member (Woodring and Thompson, 1949, p. (locality 130), at the north end of Mariflores Locks, 241) and the Pedro Miguel area is the type region of and south of those locks (Geological Survey locality 1he Pedro Miguel agglomerate member. The thickness 6009) was described by MacDonald as part of the of the formation is estimated to be at least 300 meters. Culebra formation (MacDonald, 1919, p. 533-534).
Fossiliferous calcareous tuffaceous massive sandstone
sTTIMPHY \ND LITHLOCY of the La Boca is exposed in an abandoned quarry off
The La Boca marine member extends farther inland old Gaillard Highway near Summit (locality 128). than any other part of the Panam' formation. It over- When the cuts along the present alinement of the lies the Cucaracha formation or interfingers with the Panama Railroad were fresh, MacDonald found fossils upper part of that formation. Nevertheless, if the La in similar but less massive sandstone in cuts north and Boca is correctly identified, it also overlaps the Cuca- south of Summit (localities 126 to 127b.) At locality rachia and Culebra formations and rests directly on 1271) the sandstone is overlain by tuff that MacDonald t hlie Bas ()Obispo formation. The member consists prin- identified as representing the Panamia formation. (See cipally of silty or sandy tuffaceous mudstone, flaggy his data in description of locality 127b, p. 124.) Finetuffaceous sandstone, calcareous tuffaceous sandstone, grained fossiliferous tuff and tuffaceous siltstone crop conglomerate, and coralliferous limestone. Agglomerate out at locality 132 near Red Tank, a village that has and tuff, presumed to represent tongues from the Pedro been abandoned since plate I was drafted. Flaggy Miguel agglomerate member and the main part of the tutriffl(aceous strata, ranging in grain size from sandy formation, respectively, are other constituents. The siltstone to poorly sorted gritty sandstone, are exposed stratigraphic relations of these strata, most of which in a cliff at the mouth of Rio Masambi on the east contains marine fossils, were not understood until the side of the canal. These strata are considered part of subsurface explorations of the Geological Section of the the La Boca member. They are unlike any strata Special Enigineering D)ivision revealed evidence that in the Culebra formation and, like the La Boca member they overlie the (hcaracha formation. The fine-grained elsewhere, contain molds of Acila cf. A. isthminica. st ran formerly were assigned to the Culebra formation, Cream-colored and gray coralliferous limestone of sn111(dstone to the (Caimito formation, and limestone to Emniperador type at the base of the La Boca member the Eimperador limestone nml)er of the Culebra forma- overlies, and partly interfingers with, the Cucaracha tion. No satisfactorv outcrop section showing hoth a formation on Gaillard Highway 400 meters northwest consi(lerable part of the member and its stratigraphic of the junction with Madden Highway (locality 129). relations is known. For that reason the Mirallores Similar limestone on Rio Masambi, on the east side of Locks area has been designated the type region. In the canal (locality 123), lies directly on the Bas Obispo that area there are outcrops, and relations to the Cuca- formation and has a thickness of :35 meters, the greatest


known thickness for limestone of Emperador type. plate 1, or what rocks other thaliL agglonierate ,rop A view of this limestone is shown in plate 9. It was out in the area. recently identified as the Emperador limestone member The Panama formation proper is made up of tuff, of the Culebra formation (Woodring and Thompson, tuffaceous siltstone, tuffaceous sandstone, and agglomn1949, p. 237), but is now thought to represent the La rate. They evidently represent nonmarine essentially Boca member. It is in an area where the La Boca is fine-grained tuff and tuffaceous strata that interfinger known to be present, although no continuity with other with and overlie the La Boca marine member and the La Boca rocks has been established. If the limestone Pedro Miguel agglomerate member. The geologic map is now correctly identified, the La Boca member over- (pl. 1) suggests that in the Pacific coastal area the laps onto the Bas Obispo formation. The strata in PanamiA formation proper overlaps part of the Caimito Gaillard Cut between canal stations 1720 and 1730, formation, but that relation needs confirmation. Tuff described by MacDonald as "light-colored tuff bed characteristic of the Panama formation is light gray,
locally overlapping Culebra beds" may possibly repre- rhyolitic, and contains much pumice and minute sent overlapping La Boca (Natl. Acad. Sci., 1924, p. fragments of glass (Hill, 1898, p. 200-201; Howe, 1907, 52, fig. 4). Limestone of the La Boca near Red Tank p. 116-117). Such tuff is exposed along the water front (locality 131) was referred by MacDonald to the in Panama and in street cuts in Diablo Heights. SimEmperador member of the Culebra formation, and ilar tuff near Miraflores, now included in the La Boca
sandstone and agglomerate overlying the limestone to marine member, was informally designated the Mirathe Caimito formation (MacDonald, 1919, p. 534, flores pumice by Hill (1898, p. 198-199), a name lie "section at Bald Hill near Miraflores Locks"; for other suppressed on a later page (Hill, 1898, p. 206). Coinlocality data see p. 124). In fact, MacDonald used the parison of the volcanic constituents of the Panamii and section near Red Tank to define the Caimito formation Caimito formations may afford a basis for confirming and its stratigraphic relations to the Emperador lime- or rejecting earlier correlations of tuff in the Panaini stone member of the Culebra formation (MacDonald, formation with rhyolitic tuff along the canal north of 1913, p. 569). the continental divide (Hill, 1898, p. 201; Bertrand and
The Pedro Miguel agglomerate member is a lens of Ziircher, 1899, p. 91; Howe, 1907, p. 117). The apessentially coarse-grained pyroclastic rocks. In the parent overlap of the La Boca marine member of the Pedro Miguel area, the type region, these rocks overlie Panama formation across the Cucaracha and Culebra the Cucaracha formation. The lower part of the formations indicates that their correlation deserves pyroclastic rocks, like the lower part of the La Boca further consideration. In the meantime, however, it marine member, apparently is the equivalent of the is not accepted. upper part of thick Cucaracha sections. Farther south FOSSILS AND A
the pyroclastics appear as a tongue in the lower part of The only available fossils were found in the La Boca the La Boca marine member. The pyroclastic rocks of marine member. the Pedro Miguel member, as described by Thompson Smaller Forai ifera. -Smaller Foraninifera are
(1947a, p. 18-19), consist chiefly of fine- to very fairly abundant in fine-grained strata. They represent coarse-grained agglomerate. Bedding and sorting are a more open-sea marine environment than the meager poor to moderately well developed. Fine-grained tuff fauna of the Culebra formation. M. N. Bramlette, is interbedded with the agglomerate. The thickness who examined the outcrop sample from locality 124 of the Pedro Miguel member is variable, but the maxi- and some subsurface samples, points out the abundance mum averages about 100 meters. Agglomerate of the of Siphogenerima transversa. The type locality of that
Pedro Miguel in the Miraflores area was formerly species (Geological Survey locality 6010, 130 of present
considered part of the Las Cascadas agglomerate or report) is in strata of the La Boca member penetrated was doubtfully referred to that formation (MacDonald, in the canal excavation between Paraiso and Pedro 1919, p. 533). Howe, however, realized that agglomer- Miguel. Siphogenerina also is found in calcareous ate near the continental divide rests on the Culebra sandstone at locality 128. Both the type locality of formation (1908, p. 222-223). (The Cucaracha forma- Siphogenerina transversa and Geological Survey locality tion had not yet been differentiated.) Like Mac- 6009 were assigned to the Culebra formation in CushDonald, he thought that agglomerate farther south man's account of Canal Zone smaller Foraminifera near Corozal is of pre-Culebra age (Howe, 1908, p. 223). (Cushman, 1918).
Much agglomerate is known to be present in an un- Larger Foraminifera.-The type locality of Lepidomapped area between Madden Highway and Curundu. cyclina miraflorensis (locality 132a), a lepidocycline It is not known, however, whether all this agglomerate species, represents the La Boca marine member. It represents the Pedro Miguel member, as shown on has been suggested that that locality is near the rail-


road tmmnnel north of Iiraflores Locks (Woodring and been taken seriously, Hill was inclined to consider the Thompson, 1949, p1). 241), but it probably is submerged formation pre-Tertiary (Hill, 1898, )p. 202). Bertrand by Miraflores Iake. Cole has recently described thin and Zircher (1899, p. 90-91), however, pointed out
Ctn of SpeiimenS from e tv)e lot (Cole, 1953a). that the tuff on the Pacific slope of the district to be l1e also identified and described Lepidocyclina partula, traversed by the canal is younger than strata ("grbs also a lepi(docycline species, and 1Tiogypsi na parnamisis ligniteux") now referred to the Culebra formation, and from locality 1 a, Mlac Donald's locality near Red Howe (1907, p. 117) came to the same conclusion. Talnk. Though the La Boca fossils and the Culebra fossils
(oals.-MacI)onald found two species of corals in for the most part indicate somewhat different facies, li stone at his locality near Red Tank (locality 131). they have essentially the same age significance: both Both were recorded by Vaughan from the Emperador have Oligocene and Miocene affinities. The La Boca limestone member of the Culebra formation and one member-and presumably the entire Panaui formafrom the Anguilla formation (Vaughan, 1919a, p. 209; tion--is not much younger than the Culebra formation. (eological Survey loclity 6256). The following corals, Like the Culebra formation, it is considered early found in limestone at the base of the La Boca member Miocene. The entire succession above the Las Casat localities 123 and 129, were identified by J. W. Wells: cadas agglomerate (Culebra, Cucarachla, and Panamni formations) is thought to represent the early half of
oroals fnrom limestone at base of La Boca marine member of early Miocene time; that is, the disputed Oligocene or Pananiiformation
Pauna formation \liocene. If the Panami formation east of the Canal
[Identifnicatiolln y. w. Wl oce le Zone does not include the equivalent of the Culebra 123 129
92aml-, m formation, presumably there is a slight discontinuity S ygloph~ora intperatori inuglhan .. . . .. ...
Stlyophora mordoaldi Vaugham ---- - --- between the Caimito and PanallAt formations east of
Acropora saldnsid. V'angltn_ --------------------- X the Zone.
Porites ef. 1'. d villci V:aughan --------------------- GATUN FORMATION
Mlontat..t a imperatorisv Vauglum .. . .. . .. .moar ....o ughn--------------------- X The two remaining Tertiary formations to be
ootlasrmia colata (Dunean) ----------------------- X 'X
described( are found in the Gatin Lake and Caribbean
A(ordiig to Wells, all except one of theabovespecies coastal districts. The older of the two is the Gatun for comparable species) occnr in the Emperador lime- formation, well-known for its rich fauna. In fact, the stone mnln)er of the Culebra formation and that species fossils of the Gatun formation attracted attention at (,Iftanl.(a 'osflata) occurs in the Culebra formation an early date. When Blake traveled across Panamtin )ror)(. Two( are fou(1 in the Antigua formation and in 1853 onil his way to California to join one of the three in thlie Anguilla formation of the Leeward( Islands. transcontinental railroad surveying parties, he colMlol/shk..- Thoijgh mollusks are widespread in the lected a few Gatun fossils (Blake, 1857, p. 1). Two La Boa member, they are nowhere abundant and most years later Newberry crossed Pananmi on the same of them are not well preserved. (nrpidubla sp. (locality mission and also collected some Gatun fossils, but left 125), A i'rrita? sp. (localitY 130), and T) urritella of. T. no account of his observations. At about the same colla(1c( (locality 12:) are the onlyspeciesin the families time another traveler briefly commented on fossils at COvered by chapterr A of the present report. Monkey Hill (now known as Mount Hope) but saw
lch;Iioid..- Imnestone at the base of the La Boca none at Gatun (Deck, 1855, p. 241). A search of mniebr at locality 12: yielded an echinoid identified books and magazine articles written by Californiaby, C. WV. Cooke as (lypcaster concarus?. That species bound travelers (during and after the gold rush doubtless occurs in the Caimito formation of the Rio fandinga would reveal other accounts. area and in both the Antiguia and Anguilla formations The Gatun formation was named by Howe (1907, of the Leeward Islan(ds. According to Jackson, p. 113-114). In Spanish orthography the name is (lypo(,ster galun i. a (Gatun species, was found in linme- Gat in. That, name, however, was not the earliest for stone in a swamp north of Ancon Ilill (Jackson, 1917, the formation. Hill had already used the names p. 491). The swaimp) is now filled, but limestone Monkey Hill formation and A[indi Hill beds (1898,
occuring in that region presumably is in the La Boca p. 176, 180). Howe, indeed, used both Gatun formamarinle Ilctli)er, tion an(d Monkey lill formation in a structure section
Age. The l'aanmi formation was the first forniation in the publication in which he proposed his name inii or near the Canal Zone to be given an age assignment. (1907, pl. 147), and in a later publication used only Wagner thought that reddish conglomerate and frag- Monkey Hill formation (1908, p. 228). MacDonald's mental rocks at Panami are Permian (Wagner, 1861, usage apparently established preference for Howe's p. 6, 16). Though that opinion, of course, has not name (MacDonald, 1913, p). 530). The type area is


the one described by IIowe: from Gatun to Mount Gatun Lake area, but is not known to penetrate the
Hope (Monkey Hill of Howe's time). As a result of Gatun. faulty paleontological information, Howe excluded the The Gatun formation has been subdivided in various oldest strata near Gatun from the Gatun formation ways on faunal grounds (Woodring, 1928, p. 76 77; and grouped them with the Bohio formation (1907, Olsson, 1942, p. 244-247; Thompson and Keen, 1916). p. 113). It is now known that the oldest outcropping The subdivisions adopted for the present report coinepart of the formation is not represented in the type spond to the three faunal zones proposed by Thompson region. and Keen. Though the subdivisions are based oti f'li n
The outcrop area of the Gatun extends from Maria grounds, they are simply designated lower, middle, and Chiquita, 20 kilometers northeast of Col6n (pl. 1), upper parts, at least until the study of the fossils is to Rio Miguel, 50 kilometers southwest of Col6n (fig. completed. Both fossil collections and observations oil 11), but much of that area has not yet been examined, the lithology, however, are scattered and eventually The relations of the Gatun to the next older formation some other nomenclature may be found to be more in the Gatun Lake and Caribbean coastal districts-the satisfactory. Caimito formation-are unknown. In the Canal Zone The lower part consists principally of medium- to
the contact between the two formations is covered by very fine-grained sandstone. This part of the formation the waters of Gatun Lake and even before the flooding was unknown before the explorations of the Geological of the lake perhaps all of the contact was concealed by Section of the Special Engineering Division. In some swamps. East and west of the Canal Zone, however, exposures along the Transisthmian Highway and the the Gatun presumably rests on the Caimito formation road from the highway to Maria Chiquita, a basal at outcrop localities, as shown on plate 1. So far as conglomerate of variable thickness is present. It is now known, no deposits of early Miocene age are most conspicuous along the Transisthmian Highway imincluded in the Caimito formation of the Gatun Lake mediately south of Sabanita and is thin or absent along area. The boundary between the two formations there- the road to Maria Chiquita. At locality 135 molds and fore is presumed to represent a discontinuity represent- impressions of marine mollusks were found in sandstone ing early Miocene time. Still farther east the Gatun partings in the conglomerate: in the sandstone itself formation overlaps the Caimito and directly overlies the and in ferrugineous concretions. At some localities Cretaceous(?) basement. At the west end of the out- along the road to Maria Chiquita, sandstone is at, the crop area the upper part of the formation is interpreted base of the formation and at, others, where the base as overlapping on the Caimito formation, not on the itself is not exposed, carbonaceous siltstone or mudbasement complex as previously surmised (Woodring stone, containing molds of marine mollusks, is close to and Thompson, 1949, p. 243). the base. Fine-grained sandstone is exposed in cuts on
The dip of the Gatun is low, between 50 and 100, and the Transisthmian Highway between Sabanita and flattens out northwestward toward the coast. Never- Cativa. Much of the sandstone, as at localities theless a water well at Mount Hope penetrated a thick- 136-138, contains numerous well-preserved fossils. ness of 425 meters of Gatun strata without reaching the The middle part includes the best known strata: base of formation (Thompson, 1947a, p. 20). The total those at and near Gatun, including the strata excavated thickness is estimated to be at least 500 meters and for the Gatun Locks and the uncompleted Gatun Third perhaps a considerable thickness is concealed by overlap. Locks. The three members recognized by MacDonald (1913, p. 570) and the strata he described later (1919,
STRATIGRAPHY AND LITHOLOGY p. 542-543) are in the middle part. Though sandstone
Massive medium- to very fine-grained sandstone and is the chief constituent, the middle part includes consiltstone are the chief constituents of the Gatun forma- glomerate, siltstone, and tuff. When dry the tuff is tion. They are somewhat calcareous, or marly, some- almost white and forms conspicuous outcrops in excavawhat tuffaceous, and have a clay-like matrix. The tions. It was designated fullers earth by MacDonald. sandstone contains numerous grains of black and The following section, described in a report by the
greenish volcanic rocks and is practically a subgray- Geological Section of the Special Engineering Division wake, as indicated by Boutan's (1880, p. 13) early (Thompson, 1943a, p. 10-19, figs. 5-13 to 5-22) and account, the only description of the microscopic by Jones (1950, p. 916-917, table 3), is exposed in the petrology so far published. Conglomerate and hard Gatun Third Locks excavation east of Gatun. The brittle very fine-grained tuff make up a small part of numbering of the units is that used by Thompson the formation. Basalt intrudes older formations in the and Jones.


Section of strata in middle part of Gatun formation as exposed in Section of strata in middle part of Gatun formation as exposed in
Gatun Third Locks excavation Gatun Third Locks excavation-Continued
[After Thompson and Jones] [After Thompson and Jones]
Meters Meters
12. Sandstone and siltstone 1. Massive medium- to very fine-grained, silty to
d. Massive very fine-grained silty sand- somewhat marly sandstone. Contains nustone; thin lenses of conglomerate merous shells, for most part more or less
(thickness a few cm) made up of peb- leached. Locality 153 ------------------- 31. 1
bles of volcanic rocks. Contains leached shells and few carbonized plant Thickness of section ------------------- 151-156. 5
remains --------------------------- 7.9
c. Marly siltstone----------------------- 3. 3 Units 1 to 4, inclusive, of the preceding section are
b. Clayey marly siltstone. Contains abun- shown in plate 10. The conglomerate forming unit 10
dant well-preserved shells and some probably is the same bed as the conglomerate near
plant remains. Locality 155c ..e 8.4 Gatun described by Howe (1907, pp. 113-114; 1908,
a. Lens of medium- to very fine-grained silty
and marly sandstoyfne-grained -0--. 5 pp. 228-229). In his 1908 account Howe was tempted
and miarly sundstone 0---- -1.-- -5
11. Massive medium- to very fine-grained, silty and to select the conglomerate as the base of the Gatun
marly sandstone. Contains abundant shells formation (his Monkey Hill formation of that account),
and fragments of carbonized wood. Shells but his view was influenced by faulty paleontologic
arranged in layers and concentrated in information. Unit 10 is stratigraphically not far from
pockets. Locality 155 represents units 11
andkets. 12 calty-1--------n ----ithe base of the Gatun at Gatun Dam spillway as seand 12 7. 5-9. 1
10. Poorly sorted conglomerate, increasingly calca- lected by Olsson (1942, p. 244-245). At all events
reous upward. Consists of pebbles of dense his unconformity between the Gatun and Caimito forvolcanic rocks (maximum length 10 cm) in mations, as he now realizes (personal communication),
matrix of mediurn-grained sandstone. Con- is a minor discontinuity in the middle part of the Gatun
tains shells and bits of carbonized wood. forntion.
Locality 154 ---------------------------- 3. 6 an
9. Coarse-grained tuffaceous sandstone, consisting Sandy and marly siltstone seem to be the principal
principally of grains of dark-colored volcanic constituents of the upper part of the formation, at rocks, quartz, and pumice. Uppermost 60 least in the Mindi (localities 171-173) and Mount
cm conglomeratic; thin lenses of conglonm- Hope (localities 174-178) areas.
crate throughout. Contains a few shells, Both upper and middle parts are represented west
mostly leached -------------------------- 7. 2
8. Sandy and silty tuff. Grain size decreasing of the canal. Farther south-that is, west of Gatun
downward and pumice more abundant Lake-the upper part evidently is overlapped by the
downward. Contains a few leached shells 9. 1 Chagres sandstone and its Toro limestone member.
7. Hard, brittle, massive, very fine-grained tuff, Collections of fossils west of the canal and west of
consisting chiefly of minute glass shards. Gatun Lake were made by A. A. Olsson during exploraContains rounded pieces of pumice (maxi- Gatun Lake were made A. A. Olsson during exploramum diameter generally 5 cn) ------------ 3. 6-6 tions for the Sinclair Central American Oil Corpora6. Coarse-grained sandstone, upper part conglom- tion in 1918, but his map and report are no longer
eratic ---------------------------------- 1.2 available. Some of the localities at which fossils were
5. Massive medium- to fine-grained, poorly sorted, collected cannot l)e plotted on plate 1 and those that
somewhat tuffaceous sandstone. Contains
sasotreat tuffaceous sandstone. Contains are plotted are located only approximately. Olsson's
scattered basalt pebbles, leached shells, and
bits of carbonized wood___------------------ 11.5 Anomia zone west of Gatun Lake is considered part
4. Medium- to very fine-grained tuffaceous sand- of the Toro limestone member of the Chagres sandstone, sandy tuff, and very fine-grained tuff stone, not part of the Gatun formation (Olsson, 1942,
in beds 15 to 90 cm thick. Increasingly p. 246-247).
fine-grained, tuffaceous, and1 pumiceous P 4-4)
fine-grained, tuffaceous, and pumiceous No information is available concerning the Gatun
downward ....... 33. 5
3. Massive, me(lium- to very fine-grained sonme- formation between locality 170, west of Gatun Lake
what minarly sandstone. Glass shards and near Escobal, and the western end of the outcrop area,
pumice fairly common in lowest 3 meters, where the formation emerges on the coast, as shown
decreasing upward. Contains scattered in figure 3. Collections of fossils made by geologists
shells, echinoid fragments, and fragmentary of the Sinclair Central American Oil Corporation in
carbonized and calcified plant remains.
Locality 153a ---------------------------- 21. 3 1918 indicate that only the upper part of the Gatun
2. lard, brittle, massive, very fine-grained tuff -- 1.8 is represented in the far western coastal area. That


8100,' 80'30' 80o00'

} Pifia
13 85 180 CiaTch
18 Cil 179
Cocl del Norte < 9

00' GAU00,
Belbin "LAKEr

81,00, 8030' 8000,
Base from Parama sheet of American Geographical Society's map of Hispanic America

Scale 1:1,()000,000
5 0 25 Miles

10 0 50 Kilometers


i~jTc(?) /
SChagres sandstone H- >"
Charges sandstone Caimito(?) formation

Gatun formation Undifferentiated volcanic
S and intrusive rocks

Locality where fossils were collected Figure 3.-Reconnaissance geologic map of Caribbean coastal part of Panama immediately west of CanalgZone.
Base from Panamd sheet of American Geographical Society's map of Hispanic America.

interpretation, however, and the areal geology shown Mollusk8s.--Mollusks are by far the most abundant
on figure 3 need confirmation. The matrix of the and widespread fossils in the Gatun formation. The
fossils consists of silty very fine-grained sandstone and collections at the U. S. National Museum represent a sandy siltstone. collecting span of a century. In 1853 Blake collected
FOSSILS AND AGE three species described two years later by Conrad (1855,

Smaller Foraminifera.-Smaller Foraminifera from p. 18; 1857, p. 328, pl. 6, figs. 53-55). Only one of the
the Gatun formation were recorded by Cushman (1918). fossils found by Blake is known to have survived: the
Marly siltstone in the upper part of the formation in type of "Gratelupia?" mnactropsis [Lirophora mactropsis],
the Canal Zone contains more species than those of a double-valve mold to which some inner shell material
Cushman's report. clings. Blake's form of locality citation is equivocal:


"At. ( aton, or Monkey Hill?, w here we stopped for a A total of 90 collections is being studied for tilhe few nionwn(ts, I obtained several fossil shells from the present report: 9 from the lower part of the formation, enlbankmelt iat the side of the road" (Blake, 1857, p. 58 from the middle part, and 23 from the upper part. 1i. Ile evidently e(at IlIe was not certain whether On thie basis of slight faunal differentiation, the colleethe place where the train stopped was (atun or Mon- tions from the f middle part are divided into those from key Hiill, although that uncertainty seems strange. an eastern area (east of the canal, 43 collections) and Two )f the three species hie collected (Lirophora nac- those from a western area (west of the canal and west ropsi nI ( h IIutia dari id) are not known to occur of CGatun Lake, 15 collections). On the basis of both at Monkey Hill [Mount Hop)e], whereas they do occur faunal and age differentiation, an eastern area in the
-at (intn. lThe preservation and matrix of the type of Canal Zone (15 collections) fand a western area, colmL;rop /iora 'iactropsix strongly suggests unit 1 of the prising the western coastal district (8 collections), are section on page 44. There is no reasonable doubt that recognized in the outcrop area of the upper part. As Blake picked up his fossils at Gatun. According to the shown by the data in the description of localities locality data in Coirad's description of New )erry's (p. 125-129), many collections, particularly from the fossils, Newherry on his trip two years after Blake's middle part of the formation in the eastern area, are also collected at (iaton (Conrad, 1857a, p). 72). Conrad duplicates or virtual duplicates. Three collections recorded five species, butt (Ga)b added eight others, contain more than 100 species: those from localities including the only cephalopod to be found in the Gatun 138a and 155 (both about 125 speciess, and locality formation ((abb, 1881). Some of Newberry's fossils 1471) (about 110 species). The first two are among have been found recently at the Academy of Natural Thompson's collections from the lower and middle parts Sciences of Philadelphia. of the formation, respectively. The third, one of
()ther Gaton fossils of the same vintage were collected MacDonald and Vaughan's from the middle part, is at Monkey ill (Mount IHopl)e of present terminology) especially rich in minute specimens, including 300 or in 1857 by J. Rowell. Sonic of Howell's specimens have more of i.bnostnia spermiatia and about 200 microearly nSmitlisonian Institution catalog numbers (6391- scopic shell tips of Turritclla altiira. 6395), which were entered in 1880 under the locality The scattered publications describing mollusks of the "Alonkey 11ill, near (Gatun." Most of them, however, Gatun formation are listed on pages 5-10. The most haxe Natio al lusinl atabg inmlnbers entered in 1893 important are those by Toula (1909, 1911), Brown and tind(ler the locality "near (atun." ()ne of the latter Pilsbry (1911, 1913), and Olsson (1922). Ahnlmost all series of inmTbers has the notation "collected in 1857." the large species that occur in the middle part of the It is assned that "near (iGattin" should read "MAni- formation have been described, ibut most of the minute key I ill, near (aitun." According to )all, liRev. J. species in that part, and many of hoth large and minute hm l was an ohl colla)orator of the Smithisonian species in the lower and upper parts are described for lisliitutioi ad a pioneer of 1849 in California ((Guppy the first time inii the present report. and Ill, I189, p. 307). Rowell also collected( fossils The available molluscan faunia is estimated to total in the I)o aiimuan Hem)llic. IUnfortunately some of about 350 species. In chapter A of the present report 46 his sp)eimens, inlhulilig tihe types of Pho Inctmaluo lds, species and subspcies are described and 4 others, not 7rebra bipartIita 'pir/tira, anid l'tch ,sci"i,,iratus, a re represented in the collections at hand, are recorded. alleged to Ibe from the Domininicm Republ)ic, but evi- The species included in chapter A are tabulated on page dently were collected I at lomunt IHope. (i)n the con- 48. In that table '"'f." in the locality columns indicates trary, a tow labeled 'near (iaMtun i" arently were the presence of incomplete or poorly preserved material collected in the I)oMininie:n Republic. that may or may not represent the form listed opposite
The bulk of the collections at the National M1useum in the species column. Likewise the designation sp." was gathered during the period 1911 13 by Macl)onald in the locality columns means an unidentified incomand Vaughan. Notable later accessi(mons resulted from plete or poorly preserved species that may or may not the tiehl work of ()lsson alnd other geologists of the be the same as that in the species column. The desigSincilair ('ntroli American Oil ( 'orlporation in 1918. nation "?sp." in the locality columns indicates that The most re('ent collections studied for the present the genus is questioned. The columns labeled "Other report ai'e Thompson's made in 1942-43 and my own collections" list species or occurrences not represented resulting from the 1947 field work for the present report. in the collections at hand.


The table on page 48 includes two of the most matrix on microscopic examia tion is se'In to bw
characteristic speciesoftheG atunformation: Turritella characteristic, but also )ecruse none of tile species altilira and T. gatunensis. It also includes species that occurs at Vtmos Vanmos. have living relatives in the Pacific Ocean but not in Dall's assignielnt of part of the (atun formation to the Caribbean Sea, and species that survived in the the Oligocene was the result of his conviction, first Pacific b)ut not in the Caribbean Sea (Trochita troche i- published in 1896 ((Guppy anid I )all. 1896i, p.0:). 01 Jormins, Nererita reclusiana, and N. hlelicoldes). that the Miocene of thie (Caribb)l)eanii regioli (and all
Echinoids.-C('lypaster gaturini, Encope annoctens, E. except the very latest of thie iiocenlle in so uth I easterly platytata, E. megatremna, and Schizaster panameisis were Uniited States) really is upper )Oligocene. Touila justly described by Jackson (1917). protested against an early Tertiary age for the (Gatn
Ostracodes.- Strata in the lower part of the Gatun formation, but went too far in the opposite direction formation at Cativa, for which the name Cativa marl in claiming that the Gatun (that is, the middle part of was casually used, yielded 18 species and varieties of the formation) is of late Miocene or even Plioceine -age ostracodes (Coryell and Fields, 1937). (Toula, 1909, p1. 7:17). For many years the Gatniii
formation has been considered middle Miocene A
Age.-Age assignment of the Gatun formation was
off to a good start when Douvill4 (1891, 1)p. 497-40,8) discussion of the age would be premature until the wrote that strata at Monkey Hill, Miindi, and Gatun numerous mollusks are identified. Preliminarv examnare Miocene, and a few years later ventured the ination suggests that in the Canal Zone the formation
opinion that the strata at Monkey Hill are perhaps of represents the entire span of middle Miocenie time Helvetian age, whereas those on the upper Chagres essentially the equivalent of the Cercado and Gurabo [Alhajuela sandstone member of Caimito formation] formations of the Dominican Republic-and that the seem to be of Burdigalian age (Douville, 1898, p. 592). upper part in the western area, west of the Canal Zone, Both age assignments are practically the same as those is late [ioene. of the present time. Between publication of Douvill6's PL'OCENE SEIIIES
two reports, Dall beclouded the issue by maintaining CHAGRES SANDSTONE, INCLUDING TORO LIMESTONE MEMBER
that the strata at Gatun and Mlindi are Eocene. and The youngest Tertiary marine formation, the Chagres those at Monkey Hill Oligocene (Hill, 1S98, p. 176, sandstone, overlies and partly overlaps the Gatun 180-181, 271-272, 273-274). As already outlined formation. The outerop area lies entirely west of the
(Woodring and Thompson, 1949, p). 231), Dall was a canal, extending from the Canal Zone southwestward victim of unfortunate circumstances so far as the along the Caribbean coast to a locality between Rio Eocene part is concerned. One of Hill's collections Indio and Rio Miguel, about 45 kilometers southwest was labelled Vamos Vamos, though there is no doubt of Col6n (fig. 3). Much of the outcrop area, except it was collected from the Gatun formation near Gatun in the Canal Zone and along the coast, still remains to (locality 158), apparently from strata near the base of be examined. Calcareous strata at the base of the the middle part; that is, it was labelled as though it formation throughout most of the outcrop area in the represents the late Eocene or early Oligocene marine Canal Zone constitute the Toro limestone member. memberoftheBohio(?)fornmatioi i. (Seenotationsunder The name Chagres sandstone was proposed by Maclocalities 40 and 158 on ). 115, 127.) Nevertheless Dall Donald for the sandstone forming the hills that overcertainly would have been suspicious had he arranged look the coast from Tor Point to the mouth of Rio the collections according to Iill's field numbers, instead Chagres (MacDonald, 1919, p. 532). The sandstone of arranging the real and alleged collections from is so massive that estimates of thickness are uncertain. Vamos Vamos biologically in one lot. The same MacDonald's estimate of 1,000 feet (300 meters) or more
mistake was made much later when an ill-advised early may be excessive. Miocene age was proposed for Hill's mixed fossils The Toro limestone member also was named by
(Woodring, 1928, p. 76). All except a few of the MacDonald, who designated it a separate formation
alleged fossils from Vamos Vamos have Hill's field (MacDonald, 1915, p. 26). Toro Point was specified number 17 on the specimens, in the vials, or on the as the type locality. Earlier MacDonald (1913, p. 570) labels written by Dall. Two lots bear the field number used the informal name Caribbean limestone for this 18 (a Vamos Vamos collection, locality 40a), but 17 is unit. The average thickness of the Toro is about 40 written on the labels. One lot of Turritella altilira meters (Thompson, 1947a, p. 21). praecellens (USNM 135160) has 18 on the label and
nothing but the catalog number in the vial. Regardless STRATIGRAPHY AND LITHOLOGY
of numbering, the fossils from the Gatun formation The Toro limestone member is a local basal calcaremay readily be sorted out, not onlyibecause the rock ous deposit of variable thickness. It consists princi-


Mollusks from Gatun formation

[For explanation of symbols see p). 46]


Middle part
Lower part
Eastern area

('alliosto mu (Leiotroch rrs) ercinrern Woodring,
11.Sp.-------------------------------------- --- ------------ -------- --- --- --- --- ---- --- ----- --- --- ---?sp
Turbo (Ai'far orstoma) aff. T'. ca'staflcus
( ielin- ---- -- ------------- -- ------------- ---------- --- -- ---- ------ -- ------- -- - --
Tricolia? syrtura oodring, n. sp---------- -------- --------------- ------ ---- --------- -- ------- -Nrirtiva (I Vita?) ef. N. virginea (Linn6) ----- -- --- --- --- -- -------------------------------------------7'eino, ttw (Idioraphe) spermatia Woodring,
]I.sp.--- --- ---- -------------------------- ------------ ----------------- -------------- -- --x---- ------xX ,XX ? ---- --- --- ------- ----- x
atigrilatu rimfch alum Woodrinig, n.stnbsp- X ) X -X -- -- -
(Ar plystomat~) audriorn Vr'odrinig,n. sp - __- X
(Pscudorotella) jycrrura, (Woodring) --- --- X ---- -----stemoniu m Woodring, n. sp------------------ --------- -----------(IDiaere-allus) sychsrur \Voodring. ni. sp----------------- - -x---- -----------------------AnIriclintax (Autnielimcax) gator neiisis I'ilsbry
and~lsr. - - - -X - --
(Su tjcim,ar ')telcospira telcospira Pilsbry andOls'ron --- -- ----_--------- ---- --- --- ---- x
hysftaaWoodring, n.suhsp - - ---
Cyclustrerndscris (Ponocyclus) peutaguinus
(Gh) -- --- x x -- --- --- -x---- -----x X X - x
Solariorbis (Suluciorbiv) stren gyus Woodring.
n.sp----- -- --- - --- xx --- -- --- --
(Iii paris) h yptirs ry ptius Woorlring, n.
sp andI. sbsp --- ------ -----X -- ---- ------- X--- -X
anebrs Wnoririg, nsubsp ----- --- -- -- - - - ---- - - -
Episcytriarrnalia Wooiring n. sp--------- X--- ---- --------------------------------"Airaui'" aff. "A." epulata (Pilsbry and
.Johnison). -- -Rissrgrra ( Pliusitiella) ouera Woodring, n.
sp - -- --- ------ - - -----Acrirrlhora drleta (Guppy) - - - -- -- ----------- -- ---- ---- - - - ------------('repidula c-f. C. snaculrrsa Crrnrad X -_ -- - - x
pialo Say -------- X XX-----------Calrjptraca ceurrlis (Conradl) ----- -- X XX--------------------- -- ---- ------c .
Trorhita trrciorris (Born) ---X X---- ----
('rurjtrulrr to('uiuui) rrplnm all- (lDispriloo) sprinri'aleense Rutseh_ X X XX X X. -- X ?- X ?X X- ------X X- -('heilca prrrr-etouia Brown and Pilshry------------------ - -
NIrrtza (Nrrtica?) bolus Brown and t'ilslr)ry----------X---- -----------X ?--------- -x
(Nuair-riux) raric a (TLin -. ---------- -stenotp Woodriritg, n. p X x x x x -------- x ---- x - x ?
Sfti uI, rtr B p~Iiauu (i rlli,,,) ---- ---X X X - -X -- ---- X ? *x x x X x x x
Tl'curatzra aquat Wuodring. 11. sp - x -_ x x x X -X -- x
Puoiics raju,-otralis (Brown and l'ilsbry> - X---------- -- -- -- ----brut ueu subrlarsrus (Sowerlry) - -
sf0x x is 'rs ro urtr iarrX )< X -- ----- --? ? ? ?
Nevcrita ((lossrrulaar) reclusiutra itria Woodritn subsp. --- X X sp.
(lypterita) h elicoirts (0 ray) -- X - -- - - - -
Si nom qah iicusc ('Ioula) --
cur yhcrira \Woorlring, ni. sp ---- x
yatrhi ( Browin and P1 lsbry).- ----- X-
Turritrlla (Torurrla) alt ilra C'onrard, s. I-----------------------al/ilira alltira(Conrad X -x ~ x x-- x X XX x -- ~X _x x
altilira practllcrrs I'ilstrry and Brown___ X X -X X---------------- --------------- -- - - -----atirupta Spicker_ ,_ ---- -- --X ---- --- --------ruatarrcana Hordson ---- ? X X X X X ?------------
gatuecrituaniesis Corad_ .. X X X X X sp. X X X ?~ - -- X ---------- ---- -rhyinrdcs Wrrodrirrg, n. subsp ----- - - - ---- -- ---- --mmles Brown and Pilslry.------------ ----------------------------------X
tifastiqta Nelson------ ------------ x x -- ---- -


(Trochidae to Turritellidae)
(For explanation of symbols see p. 46]


Middle part 1 pp'r part

Eastern area Western area Eastern area Western area

x~ -- -- -- -- -- ---- -- -- -- -- -- ---- --- - ----- ------ -- -- - -----4x
x-----------x - - ----- -- x-


X -- X- X - p

-- --- ---X-X
S x --- --- x s

S X ---. --- -.-..
------- -! - -- -- --- -- -- -- '-------- ----- --- -- --- ----- - - -- - - -- - - - -- - - -- - -
---- --
~~~~~~- - - ------------------- ----- --- --- --- --- --- --- --- --- - -

x -- --- ------- ---- ------- ----- ------- -- ---------- ------ --- ---~

x xx xx
x x x xx------------------------ x x x--- x x x
------- ------- --- ------- ---- --- --- -------------------------------------------------
------------- -- ---- ------ -------------?------ ---------- - - - -___ __x x
--- x xx x x------ -----x e ---- --- --- --- ---- -- -- -- -- --

------------ --- -----x XX xxxx X x----------------x --- .x x x -.x.x .xI
-- ---------------------?p----------------------------- - s.-X- X X--------- sp ----X X X ?-- X- f----------------- -------- --- --- ------------- XX

X--------------- -- - - -- - - -
-X >( -- --X -- ----- --- -------- X x x---------- -- ---- -------- ------>() x9 X I ~

x x Xx ---X------- XX X Xsp.-----------xx------------X1-- ?

X ----- -- ---- -- XX---------------x--- xx xxx x xx

- --- -- -x x

xxx x -x. ---- -------- x x x-. xx
-------- x --- --- Xx- -l ------ x x xxxx x
x --X- - -- -- ------------------x~

--IX------------------- x-- -- ---- --- -- - -

--, X xx x------------------------- --- --- --- --- x

----- - - - X? x x ->

-X --------------------------------------


pally (If lime1-coented coqulinia Inade ill) of small fi-ag- the Pacific side (Thiompson, 1947a,, p). 22). Black imiltis of bar-nacles, shiells, echinoid spines, and corals organic muck is the most widely distributed type of (14s. 11, 12). Barnacle fragments predominate at deposit. Inl fact, the geologists of the Geologicalf Seeiiliiv localil ics and( (i'osS-lbe(1illog is comminon. Lenses tion of the Special Eng-ineering Division used the inlof nieditiln- to coarse-Yraiule sandstone occur in the formal designations Atlantic muck andl Pacific muck for cc(juinai. IDescriijiomis of out crops of the Tor'o have, the Pleistocene deposits (Thompson, 1947a, p). 22). lbeeii pumblishied by \ [aclomald (19119, p. 544-545) and Accordling to Thompson's description, much of the )lsson (1942, p). 246). black muck represents swamp depositss andl is a mixture
'Ille ( liagr-es sandstone pro per is made upJ of massive of silt, very fine-grainled organic debris, and partly gei cra in i e-g-ra ii ed san dston1e am 1(1 some silt st one carbonized wood, steins, and leaves. Layers of marinle (Ill1. 1:;). U. nlike the Oat un formation, the Chiagres is fossils are found in black organic silt and calcareous nt known to include cunglonienate or tuff, and the mudl containing plant matter. They were encountered samidlstwim itself contains less, volcanic material Utan at the north end of the e-xcavation for the Gatun Locks san1(lst oi e of lie Goaun. and inl ditchies in swamps north and east of Mount
FOSSIS AN ACEHope (Browni and Pilsbrv, 1913, p. 493-494; 'MacJfoho~. -A fw mldsofmolusk frm Osso'sDonald, 1919, p). 544). Brown and Pilsbry casually A~ol~i~s.A fw mldsofmolusk frm Osso's used the namle -Mount Hiope formation, which they Anolo*Pd H Zoneli are included in thie families covered by attribiited to W. B. Scott, for Pleistocene strata near cliapter A of the present, relort: ( a,/iosloinu? sp. and ?\Loumit Hope (Brown and Pilsbrv, 19138, p. 493). Tuxidda gal u n sis 2 frm locality 194 ; Tar, itella
(ltitira s. 1. fr-om locality 195; Turbo aMr. T. castaineu?.s, ilFO'Sll'S AND AGE;
Tuw~ih 1a gat an ensl anmd TffrrnU/la nin metes? from (Coral,.- -Corals collections from localit ies near \ It.
loclit t9. lssmi' ~lomt~lzon (Ossn, 942 ~ Hope have been listed by Brown and Pilsbry (1913a,
toaiyt9.Oso 1)e~o~ doeentlv,192,1) 246- 247) appears to ) art, of' the shallow-water p. 497) and NaughAan (1919b, p). 563). They evidnl
Cailcareous deposits formlim g the ovelapping~ Toro represent, reef-flat species.
limstoe emlerof heCharessa~lson r7 he Mollusks.- -A few new species of mollusks were
limil~I' o te atmifo 2aio, described byv Dall (1912, p). 1-6) andl Brown and
A new species of ( alliostoiiw, C inda][itn (localities Pilsbry (191,_',). Brown andt Pilsbr-v listed the species 206, 206:a), ani unidenltified inold of ('racibulu in (hweadit in the two collections they studied. The few species 201 ), tind( SIgioaulax gap)])lan1(1 (locality 208) ocu in their collection from the north end of the Gatuin
n li larssnsoieP'le.Temluk of the Loc'ks excavation llicate brackish water and the
Oil iages sandstone roer nliketoee niToro ( ep)osits themselves point to deposition in a swamp. ines ton e nini er, indlica te deposit ion in water ofdeoiioalnvrmntfthlrgnubrf
iiioera ('(1e1th.marine species inl their (collectionl from a locality near
itt! ool. Ia~geSj~cie of lqu ah r fond ~ tle ount Hope, and in M a clonaId's Collections froin the IOU: 010iniest one member :t locality 196 (Olsson's same, region, is uncertain oni the basis of published (data. i/tolfo:0 Zone), is Ident ified by C AV. Cooke as C. tif Contrary to Dali's statement (1912, 1). 1), Mlac( ou' ,rsi. (-!. boir' rsi occurs in thte lInperiail forma 1o1l D onald's collect ions from thie Caribbean sidle do not.
of he 'oorao I)eert, o dil~lt e ~ I oceie r Piocne contain ainy species nowN1 living along the Pacific side. :ire probablyy late MIiocenie). I'lle Pleist ocenie mollusks aire not, described in the
'Age. -The hiagie .saiidstoe 01 s 1c(lose to thle border systematic part, of the. present, report.
I e Weli NI o(e~i :i idJ~hocne ithasbee asige~lto -l.- Aith 1i the except ion of the new species of molbotl (,I-Ivs. I'lrelinliinary exa nitilat lol of (Ile Itiolhisks lush s, the identified fossils from the Pleist ocene marine Suggest s ea lb P~liocenie, (1 despite0 tile pr1esenice of a few,- on the Caribbean side of the Canal Zone are
( a o spcissi cl a >~t~~i~ uac~juppan ndofkniowni to 1)e living in t he Caribbean Sea. DalI, and ot hem. species timht, hav1\e 1ai1:aflilmiiles. Browni andh Pilsbrv realized that their new species may
1)e found to 1)0 living when the, fauna along, the CaribiPLEIST(WEN EIEIES bean icoaist of Panauiislbetter knowni. The Pleistocenie
Si1R %TIt;I, \I'llY XN I) IIiTHIOOY (leposits- at, least the marine (lelosits-prolbably fire
Pleist ocenie illntiie dieposit-s occur at. aIt itliides of a of la te 1"leistocenie age, 1)ut may be too 01(1 for radhiofekk feet ai 1)O\ ea: level anmd In. tihe seawVard par't Of eca 11)011 datil1W. 1)111 i(I Val leys are lilt (ei'bedded withI sxvai 111)aid streaml 0'''m'1IH OIA'HN NI)FFRN1
dveJosit >. swaiiip anid sti-ieai deposits fillinig buried0 AREFAS
\llieo e, I em ~d as fa. Iniland a1ms ( minboa oni thle Ca'mribbleanu Correlation of tile rert iairY foi'nations In. dliterent sie, of t iec ( 'aml I Zone :iI: i aU11l ialoW II( )tkS (li and~iSUm age( iissigiifeits, as adopted in the present

Age Madden Basin, Panama Quebrancha syncline, Panama' Gatun Lake area and Caribbean Gaiciard CuCaaoZnasta fCanea ZinePn
coastal area, Canal ZoneGaladCtCaaZoeasofanloe


Early Chagres Tofe limestonle
sandstone mber


0 ideGfu omto Panama formation, including
2 La dBoca marine, member
--don mebe Cuca-acha formation and Pedro Miguel agglomH Iihucrahafomaio erate member Pa nama' formation
Earlcareous sandstone Cirirbrilolirmestone
_E ebr memer nermmerCrer rmionrcudo
Pyrotesio oi Caiito Caicareous sirortone eberu Caimillo embe &Ls Casadmahr agglmrtedimtnfrato
.1 Late cacrosoottn-rrre ebrformation Quebraocha limestone member formation oer Mem le member i mieao imesione member ant omto
W Vrioor mebe 7 Las Cascadas agglomerate ?
(7EBobio Boh fomto -7;a Bofrio formation
I Early Borie formation formation braywacke goit member Mie Bhofrain -? -2 Lorformatio

Gatuncillo formation Gatuncillo formation Gal uncillo formation

UJI td
2. Midl ?
,, 0
W t



o aeetcmlxBsmn ope aeetcmlnSsmn ope

Ii0 RF 4-- o rit-r ehr Lio n of T i t it-v r fori- 11i toIt Li o t1SI i ffe I I t I rCU I s.

'I o ke n i r i 7 orr1,i i io in r ie;rI t yit S t o1 IIIs ('. o f fo rrII I It ioI I i SII rot tt i tirt I- ec 111 (IIti"I. eticutl ibliltig iwirfcitri~ trlilv-.


report, are shown in figure 4. Some features cannot tulffaceous constituents of other rocks is the most be shown properly in figure 4: the age assignment for serious deficiency in present knowledge of the geology tihe Bas ()Obispo formation and Las Cascadas agglom- of the Canal Zone and adjoining parts of Panamii. orate is Oligocene(?), despite the seemingly definite Such studies are likely to yield clues to correlations of position onil the chart; the age assignment for the marine the formations that may be more convincing than the member of the Bohio(?) formation of the Gatun Lake faunal correlations. area is late Eocene or early Oligocene, not late Eocene IGNEOUS ROCKS
amil early Oligocene as the chart suggests.
d earl Oligocene as the chart suggests. details The following brief account of the igneous rocks is The correlations differ only Iin some minor details
fhc orrlatins iffe ony soe mnorbased principally on MacDonal's manuscript. on the from those of Woodring and Thompson in 1949 (fig. 2). gased princially on iaconalds manuscript on the T geology of Panam mentioned on page 4. Much
The following changes have been made in age assign- of the original manuscript including so pages of t .n of the original manuscript, mecluding some pages of the ments: Gat onello formation, middle and late Eocene..
ts: atncillo formation, iddle and te Eocene part dealing with the igneous rocks, is not preserved instead of late Eocenie; Bohio formation of all five .
inst eadl odf late Ecne; Bohio formation of all five and his rock specimens and thin sections are no longer areas, early and late Oligocene instead of only early available. MacDonald's 1915 Dublication (p. 27-30)
011010cel. .XetiPcfccata ra hc a o available. MacDonald's 1915 publication (p. 27-30) Oligocene hon containss more data on the igneous rocks than his
shown in the 1949 chart); Culebra formation, including other publications. Em)eridlor limestone member, early Miocene instead .r.a.
F"111wado. lmesonemeber ealy iocne nstad The igneous rocks may be divided mnto two age of late Oligocene(?) and early Miocene; upper part of The igneous rocks may be divided into two age Sa groups: Cretaceous(?) and Tertiary. That classificaGattn formation in western area (not shown im figure tion embodies the chief addition to MacDonald's 4), late Miocene, instead of middle or late Miocene; trement. ('hagres sandstone, early Pliocene instead of late
Niocene or early Pliocene. Though the Bas Obispo CRETACEOUS(?) VOLCANIC AND INTRUSIVE ROCKS
and( Las Cascadas formations are still considered Altered basaltic and andesitic lavas are the most
Oligocene(?), they are given a greater probable time common rocks in the basement complex, at least along range in the Oligocene. the Transisthmian Highway and the pipe-line road in
Some of the proposed correlations are unsatisfactory. the eastern part of the Canal Zone. Two samples There is no satisfactory faunal or lithologic correlation from the eastern part of the Canal Zone were examined between Mad(den hasin and the Gaillard Cut area. On by W. S. Burbank, who reports that the rocks are the contrary, at least parts of the Caimito formation similar in texture and composition to the basaltof the Quebrancha syncline, the Gatun Lake area and andesite rocks of the Southern Peninsula of Haiti the Pacific coastal area can be correlated with the lower (Woodrig, Brown, and Burbank, 1924, p. 320-330). part of the Caimito of Madden basin on fairly satis- Chlorite, calcite, and a little epidote are the principal factory faunal grounds. Plate I shows at a glance that alteration products in the two samples. (Gaillard Cut and the Pacific part of the canal are close Basalt containing unaltered olivine is exposed on to the eastern border of a pile of volcanic rocks. Ma(d- Quiel)ra(lda L6)ez (between Sabanita and Rio Agua ,IPn basin, the Quebrancha syncline, and the Gatun Clara) at the Transisthmian Highway bridge. AccordLIake area are farther seaward in the marine basin. ing to R. 11. Stewart, similar olivine-rich basalt crops The coarse pyroclastic rocks and flows of the Bas out in an extensive area northeast of the highway. O)ispo format ioi ll andm Ls Cascadas agglomerate, andl( Andesite at Porto Bello--the colonial settlement lthe coarse pvroclastic rocks in the Panamni formation 35 kilometers northeast of Col6n-is presumed to be replreseint seawardI extensions of volcanic rocks front part of the basement complex. As described by the vohlni pile. In Madden basin and the Que- MacDonald, the rock is dark. Under thle microscope briicha syncilie su(h rocks are much thinner and it is markedly porphyritic and the phenocrysts are Iare toun( only in the volcanic membr of the Bohio andesine, labr dorite, bronzite, and some augite. The formula tion and the pyroclastic-clay member of the groundmlnass is largely glassy, but contains some minute Cainiito forunnation. lyroclastic deposits ill the( Gatun crystals of plagioclase. This rock was used for conLake avea are of muih fincr grain than in (aillard crete in the construction of Gatun Locks and great ('Cul. Tuff fla.ceous (lelbriis is present in the Tertiary slabs were quarried for armnioring the Limon Bay Ilnim ttions of all the area, but is more dominant il l)reakwaters. lhe (Gaillard( Cut area and the Pacific part of the canal The Cretaceous(?) lavas are intruded by dioritic than in Maddeln bIasin, the Quebrancha syncline, or the rocks and dacitic porphyry. Though no debris from (Giatn Lke 'ca. The 'ucaracha formation, for these intrusive rocks was noticed at the few localities example, conlsists almost enlitirely of altered volcanic ash. where conglomerate of the Gatuncillo formation was
Thie lack of studies of the pyroclastic rocks and the observed, they probably antedate the Gatuncillo


formation and probably are of late Cretaceous, Pale- by many rlivyolites, the chemical analysis and additional ocene, or early Eocene age. Cobbles of granodiorite, microscopic examination show that it is dacile. found by MacDonald in the gravels of Rio Chagres The dacite at, Ancon Hill is light gray and weathers
and in conglomerate of the Bohio formation, pre- to a light creamy color. As describedI by MlacDoinald,
sumably represent a group related to the Cretaceous(?) it has a fine-grained(l texture and some lathlike pheniiodioritic rocks. crysts of plagioclase, the largest of which have fees
TERTIARY VOLCANIC AND INTRUSIVE ROCKS measuring about 1 by 5 millimeters. In thin sect ion
TE hTI ary VOLAN aND IonT the rock shows flow structure, particularly around the
Though Tertiary lavas are found east of the canal phenocrysts, which consist principally of andesinie and and are widespread west of the canal, most of the Ter- some albite. Quartz in irregular grains, some augite, tiary igneous rocks described by MacDonald and se- and a few small greatly altered needles of hornblende lected by him for chemical analysis were obtained from d re present. The ytre del stend
ire present. The penocrysts are widely scattered tffd intrusive bodies grade in size into the coarser particles of the groundGRANULAR INTRUSIVE ROCKS mIass. Though the groundmass is somewhat cloudy and
Quartz diorite.-Cocovi Island, a small island in altered, it consists principally of perthitic aggregates of Panami Bay west of the entrance to the canal, was orthoclase and plagioclase and some quartz and feldfound by MacDonald to be made up of quartz diorite spar intergrowths. Accessory minerals, inll order of deporphyry. The rock is light gray but weathers almost creasing abundance, are magnetite, inlmenite, and( apawhite. It is markedly porphyritic, the phenocrysts, up tite. A considerable amount of chlorite is present and to 6 millimeters in diameter, consisting of andesine, scattered patches of an unidentified light yellowish secandesine-labradorite, some quartz, and a little ortho- ondary mineral show in the groundmass. (See analysis clase. Some of the feldspars are partly saussuritized. 3, p. 55.) W. S. Burbank suggests that MacDonald's The ferromagnesian minerals are highly altered and for description and the chemical analysis indicate that the the most part unidentifiable; a few outlines of horn- rock is considerably altered, principally by processes blende crystals were recognized. Though the finely allied to albitization. During the construction of the crystalline groundmass is somewhat cloudy and altered, canal a quarry on the west face of Ancon Hill, at a localit seems to consist of plagioclase and shreds of ferro- ity now known as Quarry IHeights, furnished great quanmagnesian minerals. Magnetite, apatite, and chlorite tities of this dacite for use in concrete in the construction are found in the rock. A chemical analysis of the por- of Miraflores and Pedro Miguel Locks. phyry is included in the table on page 55 (analysis 1). The stocks of porphyry between the canal and MadAugite quartz diorite forms Point Farfan, on the west den basin, northeast of Gaillard Cut, include dacite side of the Pacific approach to the canal at the ferry porphyry, according to geologists of the Geological Secterminus opposite La Boca. At Point Farfan, like on tion of the Special Engineering Division. The porphyry Cocovi Island, MacDonald obtained, by blasting, rock intruding the Gatuncillo formation in the Rio Casaya that proved to be considerably altered, although of area (locality 38), for example, is dacite porphyry. The fresh appearance. The quartz diorite at Point Farfan borders of this stock and the intruded rocks are slightly is gray and weathers light gray. In hand specimens it mineralized and some mining operations were carried is slightly porphyritic and the groundmass is granular on many years ago, as described on p. 59. MacDonald and almost medium grained. In thin sections andesine thought some of the rock in this area prol)ably is granoand somewhat altered augite are conspicuous. Quartz diorite, but he found nothing suitable for microscopic is present in small irregular masses, some of which examination. appear to be secondary. Many small shreds of highly Diorite.-A minor facies of the quartz diorite at Point
altered indeterminable ferromagnesian minerals were Farfan is described by M\acDonald as quartz-bearing observed. Magnetite and apatite are accessory min- gabbro. W. S. Burbank, however, points out that erals and chlorite is the chief secondary mineral. The MacDonald's description of the mineralogical composirock was analyzed and the results of the analysis are tion and the chemical analysis indicate a classification presented in the table on page 55 (analysis 2). near diorite. The rock is dark gray, medium-grained,
Dacite.-The rock forming the Ancon Hill stock (be- and equigranular. The principal minerals, arranged in tween Ancon and Balboa), as well as Naos Island and approximate order of relative abundance, are andesine, Culebra Island in Panama Bay, was described as rhyo- augite, and oligoclase. Quartz in small irregular lite by Howe (1908, p. 230-231) and MacDonald (1915, patches is a minor constituent, which W. S. Burbank p. 28-29). In his manuscript MacDonald points out suggests may be secondary. Accessory magnetite, that although the rock has the appearance of rhyolite apatite, and ilmenite are present. Chlorite is found in and some thin sections show as much quartz as shown the rock and some of the feldspars show slight saus-


suritizat ion. WV. S. Burbank points out that the soda rock was quarried for use in facing the water-level part content of the aiialvsis of this rock on page 55 (analysis of Gatun Dam. 4) is slightly high for normal diorite and suggests that VOLCANIC ROCKS AND TUFF
tl InVOLCANIC ROCKS AND TUFF the alteration recorded by MacDonald may indicate
weak albitization Dacit.--Dacitic glassy lava from the Las Cascadas
Andsite.-- Andesite porphyry forms some of the agglomerate is included in the rocks selected for chemnistocks in the area between the canal and Madden basin. cal analysis (see analysis 6, p. 55). According to A small stock of hornblende andesite, characterized by MacDonald's description, the glassy lava forms the conspicuous needles of hornblende, is being quarried matrix of thin flow breccia. The brecciatled fragments along the road between Miraflores Lake and the Trans- enclosed in the glassy matrix consist chiefly of pyroist hmian highway. elastic rocks of the Las Cascadas. Some of the glassy
DIKE ROCKS lava contains elongated gas cavities drawn out in the
Adsite.--Andesitic d(like rocks that cut the Las direction of flow.
Cascades agglomerate are mentioned by MacDonald. The hard dacitic tuff in the Cucaracha formation,
Basalt.- Dikes and small irregular intrusive bodies mentioned( in the description of that formation, was also of almost black rocks, all grouped as basalt, are widely analyzed (analysis 7, p. 55). Thin sections of the tuff distributed southwestward from the southeastern part were examined by W. S. Burbank and R. L. Smith, of the Gatun Lake area and the southern part of Mad- who found it to be a welded tuff. The glassy base conden basin. The irregular intrusive bodies form hills; sists of compressed glass shards, for the most part in fact, most of the high hills in the southeastern part of partly or entirely altered to clay. Some of the plagiothe Canal Zone are formed by intrusive or extrusive clase (andesine-labradorite) crystals are euhedral; others hasalt. are fragmental. Decomposition products of a few unBasalt obtained from dikes at 10 localities, for the identifiable ferromagnesian minerals are recognizable most part in Gaillard Cut, was examined by Mac- and the rock has a few veinlets of calcite. Fragments
Donald. These rocks are very dark and fine-grained. of finely crystalline lavas of varying composition are Labradorite, andesine, and augite are the principal scattered through the tuff. The dark little lentils, conconstituents among the larger crystals. Some of the spicuous in hand specimens, consist of saponite (a clay rocks also contain enstatite and a little biotite. The mineral of the montmorillonite group), evidently an groundhnass is made up of laths of plagioclase and grains alteration product of compressed pumice lapillae. of augite, but generally includes a little glassy material. Andesite.-MacDonald mentioned andesitic low Magnetite and ihnenite are the chief accessory minerals. breccias and dark coarse-grained andesitic flows in the Somei chlorite and a few patches of serpentine--possibly Las Cascadas agglomerate. an alteration product of olivine- -are present. Basalt.--Some of the basalt in the southern part of
Basalt from a dike oni the Panama Railroad 3 kilo- the Canal Zone consists of remnants of flows and the meters northwest of Monte Lirio was selected for chemni- undifferentiated volcanic rocks in the southwestern cal analysis. (See table, p. 55, analysis 5.) As part of the map area include much basaltic lava.
described by MacDonald, the rock is of coarser texture A flow remnant capping Gold Hill, which forms the than the usual basalt in the Canal Zone and its feld- continental divide on the east side of Gaillard Cut, is Spars are more calcic. Hand specimens show crystal described by MacDonald as dark fine-grained basalt. faces of pyroxene that shine with a resinous luster and The larger crystals consist of feldspar, mostly labrahave a maximum diameter of 4 millimeters. Under the dorite, and augite. Augite also occurs as grains and microscope the largest phenocrysis are seen to be augite. irregular aggregates. The groundmass is distinctly Thei feldspar crystals, slightly in excess of the ferro- crystalline, though very fine-grained. It has about the nagnsiani minerals, are for the mdst part labradorite same composition as the larger crystals. Small grains anid stmie of them are zoned. A little andesine is present. and irregular aggregates of magnetite, some apatite, Augite occurs in granulla," aggregates as well as in and a little ilmenite are scattered through the rock. phenoocrysts. Magnetite, apat.'ite, some ihnenite, and Epidote in light and dark yellow irregular patches fills a few small grains of zircon are present. Secondary cracks in broken feldspars and occurs as cloudy masses minerals consist of numerous l)atches of iron oxide(?), in the interior of some feldspar crystals. The thin some serpentine that may be an alteration product of sections show no olivine, but a light yellow secondary olivine, and a few small patches of chlorite. Somei of mineral may represent altered remnants of olivine. A the fehlsl)a crystals are partly saussuritized and in chemical analysis (No. 8) of this rock is included in zoned(l civstals the altlerationi is zonally selective. This the table oni page 55.


CHEMICAL COMPOSITION in Bulletin 591. The norms of thie annlvyzed rocks were
The chemical analyses of some of the rocks described calulated by MacDonald. in the preceding paragraphs are included in MacD as nu Some abnormalities in mineralogical composition reD onald's m anuscript. A s noted in the explanatory s l i g f o a i u e r e f a b t z t o i p -b b N

matter following the table of analyses, they have already suiting from various degrees of albitization probably been published in the Geological Survey's Bulletin 591. account for the high soda and low line content of sonic Missing pages of the manuscript may contain descrip- of the rocks, particularly the dacites (analyses 3, 6).
tions of the "andesitic rock near Empire" and the "lava The low potash content is typical of many similar rocks near Las Cascadas", analyses of which were published in the (aribbean region.

Analyses of igneous rocks and tuT froin ('anal Zone
[Analysts: 1, 2, 6, 7, R. C. Wells; 3, 8, George Steiger: 4, 5, W. C. Wheeler]

Granular intrusive rocks Dike rock Volcanic rocks and luff

2 23 4 5 C

SiO 2 ---------------------------- 63. 51 57. 39 69. 20 51. 72 48. 23 62. 23 65. 17 51.04
A1203 ----------------------------18.07 15.84 15.00 15. 38 14.69 14. 95 15. 22 17.34
Fe203 ----------------------------2. 01 2. 38 1. 57 3. 35 4. 49 2. 04 2. 08 2. 88
FeO -----------------------------2. 18 5.96 1.83 7.91 5. 85 1.52 3. 98 7. 33
MgO ---------------------------- 2. 19 2.41 .69 4. 38 6. 73 .75 1. 19 5. 50
CaO -----------------------------5. 14 5.24 1.88 7.84 12. 12 3. 10 3.79 9. 79
Na2 O --------------------------- 4. 08 5. 23 5.87 4. 37 2. 55 5.08 3.71 2. 88
K20 ----------------------------.88 .84 1.81 .47 1.49 1.26 1.52 .53
H20---------------------------- 1.07 1. 09 .90 .56 1.50 S. 94 257 96
H20+ ---------------------------- .60 1.74 .67 2. 00 .98 2 .72
Tie2 ----------------------------- .33 1.35 .52 1.67 1.00 .59 .96 j 1.32
CO2 ------------------------------None Trae None None Trace Trace .32 None
P205 ---------------------------- 19 .68 10 .49 .46 .01 .25
SO3 ----------------------------- ---------- -------------------- 03 .05
cl----------- 01 _0- -- 1. o---S_ ------------------------------- .01 .01

Cr2O3 --------------------------- ----------------------------- None .06
MnO ---------------------------- .06 .18 .15 .16 .17 ----------- .06 .13
BaO ---------------------------- .03 .02

Total --------------------- 100. 36 100.41 100. 19 100. 45 100. 46 100. 50 100. 57 100. 67

I Shows a trace of V203. 2 Shows traces of ZrO2, F, and V.03.

1. Quartz diorite porphyry, Cocovi Island, Panama Bay. Clarke, F. IV., Analyses 5. Basalt, Panama Railroad, 3 km northwest of Monte Iirio. Bull. 591, p. 211, of rocks and minerals from the laboratory of the U. S. Geol. Survey: U. S. Geol. analysis Q. Survey Bull. 591, p. 214, 1915, analysis 0. 6. Dacitic glassy lava in Las Caseadas agglomerate, Gaillard Cut. Bull. 591, p. 213,
2. Augite quartz diorite, Point Farfan. Bull. 591, p. 214, analysis N. analysis E.
3. Dacatie, Ancon Hill. Bull. 591, p. 213, analysis A. 7. Dacitic tuff in Cucaracha formation, Gaillard Cut. Bull. 591, p. 213, analysis B.
4. Diorite, Point Farfan. Bull. 591, p. 214, analysis P. 8. Basalt capping Gold lill, Gaillard Cut. Bull. 591, p. 213, analysis G.


[Cross -Iddings -Pirsson-Washington classification]
1 2 3 4 5 6

Quartz ..22. 26 8.22 22. 74 2.40 20. 16 3. 06
0hrthocl:tis, 5. 00 5. 00 10. 56 2. 78 8. 34 7.78 2. 78
Albite .. .. . ... . ..... 34. 58 44. 01 49. 25 3:5. 63 20.96 42. 97 24. 10
Anorthite .. 24. 74 20. 01 9. 45 21.68 24. 74 14. 18 33. 08
Cornundum - ----- 1.22
Diopsid .-- ---- -- - .81 I 1. 19 26.26 99 11.12
Hvpersi hene ... 6. 06 12. 63 3. 15 14. 63 3. 09 1. 63 17. 40
( ) li v ille - - -- - - - .. . . . . . - - - -. . . . . . . .. .. . . . . . . . . 4 7 5 - -- - - - - - - -. .
agntite.. 2. 78 3. 48 2. 32 4. 87 6. 50 3. 02 4. 17
Ilnenite -- .60 2. 58 .91 3. 19 1. 82 1. 22 2. 43
Apatite --- - - - - 31 1. 55 1. 57 1. 24 93 _. 62

Symbols: (1), ainadorose; (2) II.5.3.5, beerbachose; (3) lassenose; (4) II.5.3.5, beerbachose; (5) III.5.3.4, camptonose; (6) I.4.3.4, yellowstonose; (8), hessose.
AGE succession of volcanic rocks is known to be present.
The Bohio formation of the Quebrancha syncline, The thick succession of that area doubtless includes which is of Oligocene age, includes a thin flow of flows and intrusives younger than those of the map area.
basalt. Flow breccias and minor flows are found in The intrusive Tertiary rocks are intruded into formathe Oligocene(?) Bas Obispo formation and Las tions ranging in age from middle and late Eocene to
Cascades agglomerate. Coarse-grained frazmental vol- early Miocene. In the Gatun Lake area the Oligocene canic rocks, in the form of agglomerates, make up the Caimito formation is intruded by basalt, but no intrubulk of the Bas Obispo formation and Las Cascadas sive rocks have been found in the next younger formaag'lomnierate and occur in other formations of Oligocene tion-the middle Miocene Gatun formation- or in the and early Miocene age, particularly the Caimito forma- still younger Chagres sandstone. In the Gaillard Cut tion of the Gatun Lake area (Oligocene), the Oligocene area and still farther southeast, the formations of early part of the Caimito formation of Madden basin, and Miocene age (Culebra, Cucaracha, and Panamai forthe Panami formation (early Miocene). Altered tuff mations) are widely intruded by dikes, sills, and stocks. is the chief constituent of the early Miocene Cucaracha. In that area, however, no Tertiary deposits younger formation, which underlies the Panami formation. than those just mentioned are recognized and they The Iatuncillo formation (middle and late Eocene) represent the early half of the early Miocene. If the and (Chliagres sandstone (early Pliocene) contain very upper limit of intrusive activity in the Gatun Lake little tuff'aceous material, and tuff in the middle Miocene area is applicable in the Gaillard Cut area and farther (GItmn formation is very fine-grained. southeast, none of the intrusive rocks is younger than
The distribution outlined in the preceding paragaph) early Miocene. Some of them, however, may be older. indicates that the woll-dated Tertiary volcanic rocks, The intrusive rocks, like the volcanic rocks, probably including the fragmental volcasics derived from a represent the period of time from Oligocene to early nearl)by source, are of Oligocene and early Miocene age. Miocene. The volcanic centers )presumably were in the area of The youngest intrusive rocks include the basalt ndifferentiated volcanic rocks in the southwestern forming (likes that extend around small hills of agglompart of the area covered by plate 1 or farther west. crate in the Gaillard Cut area (Thompson, 1947a, p. 27; Ma y remnants of basaltic flows in the southeastern 1952). The agglomerate, which represents part of the part of the Canal Zone which are not dated, except Pedro Miguel agglomerate member of the Panama
insoffr as they lie on rocks of Oligocene or early Miocene formation, is faulted into the underlying Cucaracha age, probably are of the same age as the better dated formation along a more or less circular minor fault volcani rocks. 'The fin e-grained uffaceous material dipping steeply toward the agglomerate. Movement in formations of earlier and younger age than Oligocene along the fault may have resulted principally from and early Miocene evidently was erupted at distant plastic deformation of the bentonitic clay of the localities, probably west of the miap area, where a thick Cucaracha formation. The basalt dike is intruded


along the fault. Drilling through the agglomerate, Miocene deposits at outcrop localities alywIler, iII the however, shows that some of the dikes are cup-shaped central Panainii area. The structural relations berather than ring-shaped (Thompson, 1952). tween the Gatun formation and the C(ainito formatioi-the next older formation in Mthl e (Gatun I ake and
STRUCTURE Caribbean coastal areas -are at present unknown.
STRUCTURAL HISTORY The overlap of the Gatun on the basemnt, however,
Late Cretaceous or early Tertiary deformation.-The indicates at least minor movement presumably at he strongest deformation in the known geologic history of end of early Miocene time and the regional deforinat ion the Canal Zone and adjoining parts of Panamni took probably took place at that time. The Gati formaplace after eruption of the Cretaceous(?) lavas and tion and also the early Pliocene Chagres sandstone d(ip deposition of the interbedded sedimentary rocks and gently seaward in the relatively narrow coastal strip before the laying down of the basal part of the Gatun- where those formations are preserved. The distribucillo formation in middle Eocene time. At the present tion of the (Caimito formation and the marine member time this deformation is poorly dated and the structural of the Bohio(?) formation in the western part of the pattern it produced will not be known until the base- Gatun Lake area indicates a pronounced inconformity ment rocks are studied and mapped. Almost vertical between the Gatun and those older formations or that altered tuffs on the Transisthmian Highway between the Gatun is separated from them by a fault. fault is Rio Gatun and Rio Agua Sucia strike northward. The suggested on plate 1. Minor movement, evi(dently of basement rocks elsewhere in the eastern part of the late Miocene age, is indicated by the partial overlap of Canal Zone and nearby shoN a north-south grain (Jones, the Chagres sandstone on the Gatun formation. The 1950, pl. 2). The intrusion of the dioritic and dacitic regional deformation may have taken place in middle or rocks that metamorphosed the lavas and tuffs probably late Pliocene time after deposition of the Chliagres sandaccompanied the deformation. stone, but that appears to be unlikely.
Movements during late Eocene(?) to early Miocene How far southward the Cliagres saidstone and Gatun time.-Minor and local movements during middle formation extended is not known. The Clihagres sand(1Tertiary time are indicated by coarse detritus and over- stone, however, apparently did not extend far. The laps. The earliest of these movements, late Eocene or Toro limestone mniember, at the base of the Chagres in early Oligocene, is suggested by the coarse detritusof the the northeastern part of its outcrop area, and the Bohio formation and the overlap of the Bohio on the Anomia-bearing strata at the base farther southwest basement complex in the Pacific coastal area east of the are shallow-water deposits. The conglomerate and Canal Zone. The source of the coarse detritus may other deposits at the base of the Gatun formation behave been beyond the limits of the region covered by tween Sabanitas and Maria Chiquita also represent a plate 1, both to the southwest and northeast. shallow-water facies. That area, however, is at the east
Minor movement during the middle or late Oligocene end of the basin. To the southwest, in the Gatun Lake is indicated by overlap of the Caimito formation on the area, the Gatun may have extended considerably beGatuncillo formation in the northern part of Madden yond its present inland border. The base of the formabasin and by the presumed overlap of the Caimito on tion east of Zorra Island, however, has not yet been the basement northeast of Gatun Lake. Overlap of the examined and farther southwest the inland border of the Culebra formation on the Las Cascadas agglomerate formation is under Gatun Lake, and was concealed by points to late Oligocene movement, extensive swamps before the flooding of the lake. In
The overlap of the La Boca marine member of the the area where the inland border of the Gatun is conPanama formation on the Bas Obispo formation sug- cealed, the middle part of the formation may overlap gests comparable minor movement during early Mio- the lower part, just as farther west, in the region covered cene time. by figure 3, the upper part seems to overlap both lower
Miocene or Pliocene deformation.-Regional deforma- and middle parts. If the formation extended far tion, the second period of regional deformation now beyond its present inland border, the submerged area recognized, took place during Miocene or Pliocene time. probably passed through Madden basin. Fossils charThe present structural features of the central Panama acteristic of the Gatun formation are supposed to have area were then formed. The dating is uncertain not been dredged in Panama Bay off La Boca during the only because basic data are still incomplete, but also construction of the canal (Li, 1930). Pilsbry, (1931, because the Gatun formation and the Chagres sand- p. 427-428), who examined the types and figured specistone do not have an extensive distribution. The mens described by Li, found that the few Miocene
Gatun formation, which is of middle Miocene age in the fossils, among the Recent species actually dredged in region covered by plate 1, is not known to overlie early Panama Bay, are indeed characteristic of the Gatun.


Onie of them, however, is labeled "Gatun Locks and Evidence for a major eastward-trending fault, just Spillway" and all have a matrix typical of the Gatun north of Trinidad Island and just south of the Brujas formation at and near Gatun. The record of Gatun Islands, is presented on page 61. fossils in Paiinamini Bay is spurious. So far as known the faults are steeply dipping normal
faults and many of them probably have strike-slip
STRUCTURAL FEATUE displacement (Jones, 1950, p. 906). Most of the
During the period when geological work was prac- major faults have a general northward trend, but the tically limited to a narrow strip along the canal, the trend of that group of faults ranges from about N. 300 canal appeared to cross a major antichnal crest which is W. to about N. 300 E. A few major faults, such as the located immediately southeast of Gamboa, about half- Rio Gatdin fault and a fault along the lower course of way across the isthmus, and is essentially parallel to the Rio Frijol northwest of Gamboa, trend more to the east, trend of the isthmus. When two sets of volcanic rocks about N. 700 E. The Chinilla fault, one of the group (Cretaceous(?) aniid Oligocene to early Miocene) were of major faults having a general northward trend, lies differcnitiated, however, it was evident that the anti- close to the Panama Railroad south of the embayment clinal crest along the canal is a minor feature in a belt of of Gatun Lake formed by Rio Agua Salud and Rio Tertiary rocks extending obliquely across the isthmus. Frijolito. When MacDonald and Vaughan examined
Plate, 1 shows a marked contrast between the Gaillard the fresh cuts and collected fossils from the Caimito Cut area and the region to the north and east. Though formation along the railroad in 1911, they had no way the numerous minor faults and folds of the Gaillard Cut of knowing that strata older than any along the canal area reflect the detailed work that has been carried out or railroad (strata of the Gatuncillo formation) crop there, its location with reference to the trough of the out only 200 meters east of the railroad. Tertiary marine basin may have a bearing on its struc- Jones' geologic map of the Gatun Lake area (1950, tural features. The Gaillard Cut area is in the transi- pl. 2) shows many faults and fractures not shown on tion zone between a volcanic sequence and a marine plate 1 of the present report. sequence, and the cover of sedimentary strata in the The structure of the volcanic rocks west of Gaillard transition zone is thin. Cut is practically unknown. Detailed field work east
The largest well-defined folds-Madden basin and of the Gaillard Cut area should show whether there is Quchrancha syncline-- lie east of the Canal Zone in any correlation between the thin sedimentary cover the trough of the Tertiary marine basin. Madden and the structure of the Gaillard Cut area. Two
basin has the greater structural relief. It is the only characteristic formations of the thin sedimentary cover area where late early Miocene marine deposits have do not extend far east; the Culebra and Cucaracha been found anid they are almost exactly at the middle formations. The distribution of those two formations of the isthmus. Madden basin is a broad gentle fold in the complexly faulted Gaillard Cut area determined trending north-northeastward. Toward the south it the course of the canal. Both are readily eroded and flares out in an area where the geology is not well form topographic basins between irregularly arranged known. As shown by Reeves aiid Ross (1930, pl. 6), hills of basalt and agglomerate. a narromw belt of relatively steeply dipping rocks (20'
to 45') extends northward from Rio Chagres on the MINERAL RESOURCES
west side of the basin. The floor of the basin may be MiETALLIC MINERAL DEPOSITS
irregular through overlap of the Bohio formation by (Id.--Gold ore has been mined in two districts: in the Caimito formation. the basement rocks southeast of Sabanita and at a
Qluebrancha syncline also trends north-northeast- stock of dacite porphyry southeast of Gamboa.
ward, but is more sharply folded than Madden basin. I am indebted to R. H. Stewart for guiding me to the The southlward-p)lunging ant incline between Quebrancha area southeast of Sabanita. Evidence of three periods syncline an(ld Madden basin is greatly modified by the of mining activity may be seen along streams immediLimno fault. ately north and northeast of Cerro Santa Rita (at the
The niortheastward trending anticline in Bohio summit of which is located the 268-meter triangulation Peninsula, in the (Canal Zone, appears to be well station plotted on plate 1): remnants of large stone definc(led. The interpretation that it extends farther mortars pointing to aboriginal operations; caved and southwestward, and there reaches its greatest structural also almost imperceptible adits associated with a relief, is adopted to account for the upper Eocene or French boiler still standing upright; and modern adits. lower (Oligocene strata of the marine member of the The aboriginal operations suggest the origin of the Bohio(?) formation in the northern part of the peninsula name for Bahia de las Minas, the bay into which the ending in Palenluilla Point and on Triniulad Island. streams drain. When Mr. Stewart first visited this


region in 1947, the boiler fire-box door (now missing) Gold value (as of about 1912) of samples collected in Rio Sardanilla bore the name of a French manufacturer and the date area
1883. The country rock is olivine-rich basalt, a typical [Extracted from manuscript by D. F. Madcl)onldlJ
. Odue of gold exposure of which is readily accessible at the Trains- sa m ple ton,
isthmian Highway bridge across Quebrada L6pez, a Float from quartz vein $6. 0---------------------------small stream 1% kilometers in a direct line northwest End of open cut-------------------------------- -- 1.04
of the junction with the road to Nueva Providencia. Open cut .------------------------------------ 41
Outcrop, top of ridge -------------------------------- .20
The ore occurs in sulphide-bearing small quartz veins. Lower part of cut ---------------------------------Trace
No data are available on the mineralogy and tenor of
the ore or on the tonnage that has been mined. Alauganese.--Plate 1 was extended far enough to the
S. north to show the location of the southern of two manGold-mining operations at a stock of dacite porphyry
'7. Quebrada de Oro, a small northwestward-flowing tib- tram line extends from the prospects to the coast near
Quetada d Ro asal orh wesw lotin ti- Nomnibre de Di6s. The country rock consists of strongly utary of Rio Casaya. Locality 38 is located on Que- ete deformed, lo-w-grade mietamnorplue rocks-quartzite,
brada de Oro downstream from the adits (pl. 1). Remin- .leous mes hi robay e
nants of mine and mill machinery and stretches of tram sliceous limestone, icaceous sist (probably metatrack are strewn along the stream. r. AdrianBouche, morphosed tuff), and greenstone (highly altered altrack aire strewn along, t-he stream. Mr. Adrian Bouche, 7
the present owner of the property, glomerate)-all representing the Cretaceous(?) baseof Pedro Miguel, ment complex. The ore deposits are manganese oxides
orally reported that an English Company installed the mine and mill in the late 1870's or early 1880's, but associated with red jasper. Boulder-like masses of ore mine and mill in the late 1870's or early 1880's, but
that there is no evidence any gold was produced. The form great trains down the slopes and streams. These .n.t deposits were descril)ed briefly by Sears (1919) and are
adits are located in a narrow aureole of mildly contact- described in greater detail by Simons in a recent pubmetamorphosed sedimentary rocks of the Gatuncillo formation at the border of the porphyry stock. No lication (Roberts, R. J., and Irving, E. M., 1957, p. 119attempt was made to enter the caved adits. 128), fromwhich t lie preceding sentences were abstracted.
ttem was mad t ere caed its In the publication just cited Simnions mentions a minor
Other adits and pits are located in the same stock manganese prospect in Madden basin, south of Rio
of acie orpyry aros th dvid an 400 ietrsmanganese prospect in Madden basin, south of Rio of dacite porphyry, across the divide and 700 meters Chilibrillo and about 2 kilometers south of Casa Larga. south of locality 38, near the head of a tributary of According to a written communication from T. F. Rio Sardanilla, which flows southward and westward Thompson, shallow pits and trenches scattered over an toward the Panama Canal. Boutan (1880, p. 31-32) area of about a hectare show aggregations of manganifmentioned a road built to haul machinery to a gold erous concretions and lenses in the oio formation.
erous concretions and lenses in the Boluo formation.
mine on Rio Sardanilla. The last French map, in the
report of a Commission of the second French canal NONMETALLIC MINERAL DEPOSITS
company that includes an account of the geology by Limestone for cement.-Limestone in the Quebrancha Bertrand and Ziircher (1899), shows near Rio Sardanilla limestone member of the Caimito formation is at a "mine de quartz aurifire en exploitation." present the most important nonmetallic mineral deIn his unpublished manuscript, written about 1918 posit. The limestone is quarried by the Cia. Cemento and mentioned on page 4 of the introduction of the Panami, S.A., immediately east of the Transisthmian present report, MacDonald reported that none of some Highway on the east limb of the Quebrancha syncline 40 samples from the most promising veinlets, "about (locality 62, pl. 1) and is processed as an ingredient for 22 miles east of the canal opposite Las Cascadas," cement in the company's adjoining plant. The thickshowed gold values of more than $1.00 to the ton. ness and properties of three grades of limestone and one That statement evidently refers to the Quebrada de Oro of calcareous siltstone are described in Thompson's area. He also reported on samples collected "a mile (1944) detailed report. The reserves are enormous. more or less in a southeasterly direction from these Other limestones in the Caimito formation of Madden [those of preceding two sentences] old workings"; that basin and the Gatun Lake area, the Emperadorlimestone is, in the Rio Sardanilla area. The gold value of his member of the Culebra formation, and at the base of samples is as follows: the La Boca marine member of the Panamdi formation


miay be suitable for cement. According to an oral grain containing land plants, and lignite. Olsson's communication from Thompson, the widespread lime- Gatun rests unconformably on the Uscari formation stones of thle Gatuncillo formation are too high in (or better Uscari shale), which consists almost entirely magnesia. of moderately deep-water fine-grainedrocks (Olsson,
lock for, coI('4tructio. -MacDonald (1915, p. 35-38) 1922, p. 10). Light oil issues from fractures in strongly ide(quately covered construction nmaterial used in thile reformedd strata of the Uscari in the type region along building of the canal. The great quarry in dacite on Uscari Creek. The Uscari is of late Oligocene and early the west face of Ancon Ilill, the quarry in basalt at Miocene age and corresponds in age to the Caimito Susa till adjoining the Balboa docks, and the quarry formation of Madden basin. The oldest outcropping in basalt on the west side of the Pianama Railroad 3 Tertiary strata in the southeastern part of the Bocas del kilometers northwest of Moiinte Lirio, are reminders of Toro area are limestones, probably of both Oligocene the construction period, and Eocene age. The presence of subsurface marine
Since MacDonald wrote his account, a quarry has strata of Eocene age is a reasonable expectation. There been opened in hornblende andesite on the Chiva are two important differences between the two areas.
Chiva Road 6, kilometers northeast of Pedro Miguel. No oil seeps have been found in the central Panamd area and nothing in the Oligocene and lower Miocene
oIL PossIILITIrS outcrop section closely resembles the almost uniformly
Though the central Pananni area of Tertiary marine fine-grained rocks of the Uscari shale.
sedimentary formations is small and the total thick- Three districts in the part of the central Panama ness of marine strata is moderate, the oil possibilities area covered by plate 1 are promising for testing oil deserve considleralion, especially since the discovery in possibilities: the Gatun Lake district, Madden basin, 19 6 of oil in the ('osta Rican part of the Boetas del and the Pacific coastal district east of Panami City. Toro area. The southeastern end of the Costa Rican Gaiun Lake (district.--Estimates of outcrop and probpart of thle Bocas del Toro area is shown in figure 1. able maximum subsurface thickness in the Gatun Lake At the time of writing (Sept., 195() the discovery well, district are as follows. Union O)il Co. No. 2 Cocoles, located 1 kilometers
north of the international boundary, had just been stKnatcd outcrop and probable maximum subsurface thickness of
(*unpleted al]d strnatigraphic dlata had not been released. sedimntary rock formations in Gatun Lake district
Il niiiv respects thie strattigraphic succession in the Alaximum
outcrop thickness thickness in
southeastern part of thle Bocas del Toro area is similar Fatio, itr kneters methicknessin
Fo ainin meters meters
to that in the central Panami area, which includes the Clhagrs sandstone .........250 250
Canal Zone. On the islands of Bocas del Toro Archi- Deposits of late Miocene age -------- Overlapped 100 pelago a thin section of carbonate and other rocks of Gatun formation -------------------250 500
(r elosits of early Miocene age_ ----- ve(rlap~ped 300
Pliocene age crops out. They are underlain in the psits of early Miocene ae Overlapped 300
.Cainlito formation 300 400
archipelago and on the mainland by Miocene strata, Chnio formation ----------------- 300 400
Boluo formation --------------------300 300
designated by Olsson the Gatun stage or formation Marine member of Bohio(?) form(Olsson, 1922, p). 10 -16). The upper part of Olsson's tion -------------------- 100 250
(latun consists of carbonate and fine-grained, calcareous Gatuncillo formation 25+ 300
(letrital rocks of late MNiocene age, correlated with the
T otal ----------------------- 1,225+ 2, 400
upper part of the Gatiun formation in the western area
of the present report. The lower part of Olsson's The outcropping formations in the Gatun Lake
Gatun corresponds to the late middle Miocene middle district are marine, with the exception of the Bohio l)art of the Gatun in the Canal Zone and also to the formation, which is nonmarine throughout most of the late middle Miocene upper part in the eastern area, area. On Barro Colorado Island, however, the upper although the depth-facies in the Boeas del Toro basin part of the Bohio includes thin marine tongues of someis shallower than that of the upper part in the Canal what calcareous, medium-grained subgraywacke, sugZone. The equivalent of the early middle Miocene gesting that the nonmarine coarse-grained rocks are
lower part of the (latun in the Canal Zone is missing replaced seaward by marine rocks of finer grain. at the outcrop in the Bocas del Toro area or is partly The upper part of the Gatun formation consists of re)resented by nonmarine conglomerate, rocks of finer more or less calcareous, sandy and silty rocks containing


a clay-like matrix. The fauna, which includes pelagic a sample of readily disintegrated limestone from the Foraminifera, a few pteropods, and a rich assortment of core. A synopsis of the core is as follows: benthonic foraminifera and mollusks, indicates a moderate-depth environment (50 to 100 fathoms; outer Log of Core Ho -5, drild i Gtn Lake
Th ic knes.q
neritic zone of forthcoming "Treatise on paleoecology" o,,;"')
to be published by the Geological Society of America). Lake sediments -------------------------------------0.9
The late Miocene upper part of the Gatun in the western Caimito(?) formation: .is overlapped by the Bentonitie tuff grading downward into sandy siltstone area, w est of the C anal Zone (fig. 3), is overlappedin basal 3 m---------------------------------11. 2
Chagres sandstone, but is presumed to be present in Gatuncillo formation: the subsurface section. Hard fossiliferous limestone grading downward into
Deposits of early Miocene age are unknown in the soft mary limestone in lower 1.9 m --------------11. 5
Gatun Lake district. That they were deposited there Sandy siltstone and thin beds of tuff and limestone 14. 4
is indicated by the Caribbean faunal affinities of the Total thickness ------------------------------ 38. 0
early Miocene part of the Caimito formation in Madden basin. As it is unlikely tha they were removed before The presence of the Gatuncillo formation 1 .2 meters
deposition of the Gatun formation, it is concluded that below the bottom of the lake sediments can hardly be they are overlapped by the Gatun, which, along the accounted for without an assumption of a. major fault trending a little north of east, and lim just north of northeast border of the central Panamd area, overlaps trending a little north of east and lying just north of the Caimito formation and rests on the Cretaceous(?) Trinidad Island and just south of the Brujas Islands basement. group. The Caimito formation is not known to overlap
Except on Barro Colorado Island, the Caimito fora- the Bohio formation anywhere in the central part of the
Except on Barro Colorado Island, the Caimito formaGatun Lake area, although in the northeastern part of tion consists of moderately coarse, shallow-water, the area, north of Nueva Providencia, it evidently highly tuffaceous rocks and thin algal-foraminiferal overlaps both Bohio and Gatuncillo. The strata in the limestone. Though the lower part of the Caimito on S. core hole overlying the Gatuncillo formation do not
Barro Colorado includes thin algal-forainiferal lime- n
. .suggest, overlapping deposits. Nevertheless the siltstone, it is made up chiefly of medium- to very fine- stone strongly sugg ests the tuffaceous siltstone of the stone strongly suggests the tuffaceous siltstone of the
grained, somewhat tuffaceous sandstone. These finegrained, somewhat tuffaceous sandstone. These fine- Caimito exposed on the south coast of Pato Horqueto grained rocks contain a moderate-depth fauna. At one Island (locality 55a, pl. 1), the island in the Brujas locality (54n) silty, very fine-grained sandstone contains numerous discoasters and other pelagic cocco- group west of the core-hole site. If these suggestions tamns numerous discoasters and other pelagic coccoare correct, the core hole passed through a fault at a lithophores and numerous pelagic Foraminifera. The depth of 29.7 meters below the surface of the lake-a outcrop section of the Caimito on Barro Colorado, like fault having a stratigraphic displacement of about 300 that of the Bohio formation, points to progressively meters. No evidence indicating a fault, however, was deeper water and finer grain size in a seaward direction. corded by the geologist who prepared the log. As a . .recorded by the geologist who prepared the log. As a By the same line of reasoning outlined for deposits of e
. matter of fact., a fault, of that, character and of the early Miocene age, the Gatuncillo formation is expect- tren just specified accounts for the marine member of able in the subsurface section of the Gatun Lake district.
That expectation recently was realized, when the the Bohio(?) formation on Trinidad Island much more .ha .xetto 'eetywsraiewe h satisfactorily than plate 1. The Gatuncillo formation,
Gatuncillo was indentified at a depth much shallower satisfactorily tan plate 1. The Gatunillo formation, than expected. In 1955 R. H. Stewart, of the Panama consisting chiefly of moderate-depth siltstone and mudstone, is a likely source for oil throughout the Canal Company's MN'eteorological and Hydrographic '7
Canal Company's Meteorologic and Hydrographic central Panamh area and its limestones are suitable Branch, examined the cores obtained in Core Hole reservoirs.
CH-5, drilled in 1946 at a locality in Gatun Lake 325 rs Iadden basin.-The following table shows estimates meters south of Guava Island, a small island of the of outcrop and probable maximum subsurface thickness Brujas Islands group. (The core-hole locality is 1.3 in Madden basin. kilometers east of locality 55a of plate 1.) The cores include a considerable thickness of fossiliferous lime- Estimated outcrop and probable maximum subsirface thickness of . sedinantary rock formations in Madden basin stone, logged as part the Caimito(?) formation when sedintay rock formations in laddn basin
73Inxi ini
the core hole was drilled. Mr. Stewart, however, ottropneo v,,,tinie
thickness thickness
thought it probably is a limestone of the Gatuncillo Frmatio (etefs) vd,,s,
Caimito formation -------------------- 450 450
formation and his suspicion was confirmed when W. S. Bohio formation --------------------- 0-200 300
Cole identified Heterostegina ocalana, Lepidocyclina Gatuncillo formation ----------------- 300 500
macdonaldi, L. chaperi, and Asterocyclina georgiana in Total -------------------------750-950 1,250


As in the Gatun Lake district, the bulk of the Bohio Adoption of the preceding terms for the types of
formation consists of nonmarine boulder conglomerate, genera, which have the advantage of brevity, was At the continental divide the upper part of the forma- prompted by Iredale's (1939, p. 223) usage in his Great tion includes thin lenses of algald-foraminiferal lime- Barrier Reef report. Monotype, however, has been stone. In the Quebrancha syncline, northwest of substituted for haplotype. Iredale's usage was based
Mwaddhen basin, the Bohio is made up of graywacke grit, on Jordan's, who in turn picked up terms from Cooke, the basal part of which includes marine siltstone. In but also added one of his own. Those interested in the the northern part of Madden basin the Caimito forma- origin and varying usage of the terms in the preceding
tion overlaps the Bohio. two lists will find definitions and citations in Frizzell's
The Gatuncillo formation evid(lently rests on an useful "Terminology of types" (1933). It is entirely uneven surface of the basement complex. Reeves and appropriate to use the term "type" for a species and a
Ross (1930, p. 18, pl. 5) mentioned andl manpped a small genus. There can be no confusion: the type of a species outcrop of dioritic rock near the head of Rio Azote is a specimen, whereas the type of a genus is a species.
Cabaullo, just south of the present south shore of Madden The following new subgeneric names are proposed: Lake. This outcrop evidently is the top of a basement Acpystomna, subgenus of Teinostona, Vitrinellidae.
hill or ridge, on the sides of which the Gatuncillo is Type: Teinostoma (Acpystomna) andrimn Woodring, n.
overlapped by the Caimito. Practically pure quartz sp., Gatun formation, Miocene, p. 70. Gender neuter.
e PDiarrecallus, subgenus of Trinostorna, Vitrinellidae.
sandstone in the upper part of the Gatuncillo is exposed Teiosto, (Diasencallts) o ichnuft Woodring, n.
Type: Tnostoma (Diaeallu r) Uschnu 10 during, n.
along the road from Casa Larga to Laguna, near sp., Gatun formation, Miocene, p. 71. Gender masculocality 13--the only locality where such sandstone was line.
observed(l in the area covered by plate 1. IIapalorbis, subgenus of Solariorbis, Vitrinellidae.
SIType: Circulus liriope Bartsch, Recent, Gulf of CaliPacific coastal district cast of Pavand ("Ct.--In the fornia, p. 75. Gender masculine.
Pacific coastal district east of Panam' City, the Hyptlcrita, subgenus of Ncvrcrita, Naticidae, Polinicinne.
Gatuncillo formation is overlapped by the Bohio forma- Type: Natica heliroides (Gray, Recent, Baja California
tion. The Gatuncillo reappears farther east in the to Perd, p. 92. Gender feminine.
valley of Rio Bayano, 45 kilometers east-northeast of GASTROPODS
the eastern border of plate 1 (Terry, 1956, p. 32).
ESCRIPTION OF TERTIARY MOLLUSKS Trochids are rare in the Tertiary formations of the
The formal description of species is held to a mini- Canal Zone and adjoining parts of Panamd. Each of mum. Lengthy descriptions almost invariably include the two species of Calliostoma herewith described is
matter at the generic level which is of no value in the represented by two specimens. In addition three other discrimination of species, trochids are recognized: a minute "Alargarites" from
The following terms are used for type material of the middle part of the Gatun formation; an exfoliated
species: apical fragment sculptured with nodose spirals, eviType: A specimnien selected by the describer as the name- dently a calliostome, also found in the middle part of
bearer of a species. Also known as holotype. the Gatun formation; and an incomplete impression,
Parn: type: A specinen showing a feat ure, or features, not probably a calliostome sculptured with weakly noded
shown by type. Also used by others for any specinin, spirals, from the Toro limestone member of the Chagres other than type, on which the description of a species is sandstone. Each of these three trochids is represented
Syntype: A spe)inien in a lot of two or more on which a by only one specimen.
species is based, but none of which was selected by tlhe
describer as the name-hoarer. Also known as cotype. Subfamily MARGARITINAE
Lectotype: A syntvpe subsequently selected as the name- Genus?
Ne(!otype: A specimnen, from the same locality and horizon, "'Margarites" species
selected as tie wumie-bearer to take the place of destroyed iite, very thin-shelled, outline naticid, whorls
.Mnte, very thin-shelled, outline naticid, whorls Or lost, tyype nat( rial.
Topolpe': A specimne from the samine locality :and horizon rapidly eilargiig. Protoconich consisting of a smooth
as the n:ine-bearer. naticoid whorl. End of protoconch marked by fine
Ternis used for types of genera are as follows: closely spaced axial and spiral threads. Both sets of
threads gradually become more widely spaced and on
()rthotyvpe: T pl by1v origiitl designationa I
Mo Nlyld : Type by itonotlvpy. Also known as haiIlotl), later pal't of peiiult they disappear, the early part of Tautiot vp: Type by taitonymy. Ihe lipeilt hearing a siural thread, a thread on the
Log1 tlw: '1Tr1e ty subsequent tlsign:tlion. shoulder a id widely spaced retractive axial threads


between them. Body whorl smooth. Outer lip broken foliated patches are very weakly sculptured, aside from
far back. Columellar lip incomplete. Umbilicus evi- the strong peripheral spiral. That the type is not dently very narrow, umbilical border broadly rounded. mature and that the peripheral spiral is reduced near
Height 2.4 mm, diameter 2.2 mm. the outer lip of mature shells are shown by an exfoliated
This curiously sculptured species represents an un- body whorl fragment from the type locality-the only known genus of the Margaritinae. The outline and thin specimen other than that illustrated. This fragment shell suggest "Solariella" iridea Dall (1889, p. 382), indicates a body-whorl diameter of at least 30 dredged by the Blake off Cape Florida at a depth of millimeters. 193 fathoms. "Solariella" iridea, however, has more In outline of spire, strongly carinate periphery, and
inflated whorls, no axial sculpture, a faintly undulated almost smooth base, Calliostomna metalium is allied to spiral near the suture, a wider umblicus, and elongate C. aurora Dall (1889, p. 366, pl. 37, fig. 2), dredged at a nodes on the umbilical border. Though "Solariella" depth of 140 fathoms off Barbados. (Dall also recorded iridea was described as a variety of "Solariella" lubrica a fragment from a depth of 576 fathoms.) C. metalium, Dall, it is not closely related to that species, which is however, lacks the noded spirals of C. aurora and the the type of the genus Suavotrochus (Dall, 1924, p. 90), basal spirals of the fossil are even weaker. described as a section of Solariella. Occurrence: Chagres sandstone (early Pliocene),
Occurrence: Middle part of Gatun formation (middle localities 206, 206a.
Miocene), eastern area, locality 155c. Subgenus Leiotrochus Conrad
Subfamily CALLIOSTOMATINAE Conrad, Acad. Nat. Sci. Philadelphia Proc., p). 288, 1862.
Genus Calliostoma Swainson Type (monotype): Lciotrochus distans Conrad, Miocene,
Swainson, A treatise on malacology, p. 351, 1840. Type (logotype, Herrmannsen, Indicis generum malacozoorum, Assignment of Calliostoma eremum to Leiotrochus
v. 1, p. 154, 1846): Trochus conulus Linn6 (cited by Swainson has the advantage of indicating that this species has as "conula Mart."), Recent, Mediterranean Sea. an umbilicus. It is doubtful, however, whether the
Subgenus Calliostoma s. s. strongly sculptured C. eremnum and its allies are closely
related to the faintly sculptured C. distans. For the
Calliostoma (Calliostoma) metalium Woodring, n. sp. characters of C. distans, reliance is placed on specimens
Plate 18, figures 12-14 in the U. S. National Museum from Yorktown, Virginia,
A imperforate very weakly sculptured, onnoded labelled C. briani Conrad. According to Dall (1890.An ie oae ofr mediy s. ze o n oded 1903, pt. 2, p. 402, 1892), who handled specimens
carinate callistome of medium size. Whorls rapidly identified by Conrad, C. briani is C. distans. The C. enlarging, outline of spire concave. Whorls, except distans of the Maryland Geological Survey Miocene body whorl of mature shells near outer lip, very volume (Martin, 1904, p. 258, pl. 61, fig. 6) is imperstrongly carinated by a peripheral spiral, which is forate and has moderately strong sculpture. Evidently visible on spire whorls adjoining anterior suture. Three it is not C. distas, as it does not agree with Conrad's weak spirals visible on earliest preserved whorl, which description. is somewhat exfoliated. A few very faint spirals visible dAsi t, As suggested by Gardner (1926-47, p. 619-620,
on anterior part of other spire whorls. Body whorl 1947), a more natural grouping of perforate and inmbetween suture and periphery bearing weak spirals. perforate species of Calliostoma may possibly be gained Base bearing faint spirals adjoining periphery and wider faint spirals adjoining columellar lip. Columniellar lip through a study of the development of the sculpture. everted, molded against base of shell except n3ar base Calliostoma (Leiotrochus) eremum Woodring, n. sp.
of lip. Plate 22, figures 3,5
Height (almost complete, but crushed) 19.5 mm,
diameter (incomplete) 24 mm (type). A perforate calliostome of medium size. Whorls
Type: USNM 561430. of spire slightly inflated, body whorl strongly inflated.
Type locality: 206a (Stanford Univ. locality 2699, Sculpture of spire whorls and of body whorl between Caribbean coast near mouth of Rio Pifia, road cut on periphery and suture consisting of strongly noded west side of river about 90 m. west of road fork, Panama; primary spirals (3 on earliest preserved whorl, 5 to 6 same locality as USGS 16937), Chagres sandstone. on penult, and 9 to 12 on body whorl). A weakly
Though the type is somewhat crushed and evidently noded secondary spiral in some interspaces. On late is immature, the characters of this weakly sculptured, whorls some secondary spirals are transformed into nonnoded, carinate species are well defined. Much primaries by becoming wider and more strongly noded.
of the type is more or less exfoliated, but even unex- Base sculptured with 10 or 11 primary spirals. A


sconiidar spiral priesenit or il)Selit in interspaces oil (1)1111 un), evidently is tite Panamtic species named IntIse. Nodes ol b~asal spirals long, low, anid not well Turbo :axo0m,? Jby Wood (1828, p). 20, p1. 6, fig. 45) dlledt. Elge of liniibilici not shiarly anilated ai year earlier; that is, it Is a species of the subgenuis anid therefore 'un~ctioni of basal anid coltiniella r lips ( 'ulupoma, Gray (Gray, M. E., 1850, p. 87; type (logonot 1n1-iilatedl. Ihitersjpaces ()ii b~ase anid umblilical type, Cossinainn, 1895-1924, pt,. 11, p. 116, 1918): wd il I ~lilii iniieriiiost b~asal spiral roughiened lby Tuxbo flu cluos Wood, cited by Cossmiann as Tffrbo 4ixial wrinkles. Remainder of ulnlbili('ail wall siltootli, ftmhtUls Gray), Recent,, tropical eastern Pacific), a'side fromt subdued growth lines. characterized by a deep central pit and granudar ribs
Iheigit, (inicomplet e) 17.5 mmn, (lianeter 19 niim onl the operculumll.
(I1 ype). Height (zilmost, complete) 18.7 inm, (liameter Many years ago Jredlale (1915, p). 444) discussed
19 11111 (parattype). Swainson's type designation, but, apparently onl the
I' NPe : USN'M ;361811ii ; para type, Stanford Uniiv. tacit assumpjtion that T'urbo murinor'uv Inn6 is the Typ~e localit v : I 55c (USGIS 16915, Gathm Thlird1 type of I irbo, hie considered Murluarostna to be a Locks excaviationl, east side of excavattion, 1 mile (1.6 synonymi of Turbo. Thiele in his Hiandbuch (icr SYSkinl) north of (hit un Lake, Cianal Zonle), middle part, teimtiscei VWeiclitierkunde and Weitz hii his treatise of Gattun, format ion. on fossil gastropodls have called attention. to the availThis species is represented by two specimens, 1)0111 ability of .Alarmurosluma in place of the better known Collect ed at, the Gatt iii Thirld Locks. It lims a less Senectus Swainson (1840, p. 348; type (logotype),
aigiila tedt 1t1biia i~rrHan Clo nw ra m H rinse, -, v. 2,1). 4:38, 1848: Turbo chrysMaiv(1917, p). 133, 1)1. 24, fig. 19), froni tile miiddle os/urnous Liniu6, (cited by Swainsoii as ''chr?/sostoinvS Mt *cu c ua I fnIa tinfth )4Iiiihf I~ c~in I at.D hc is anl objective synony-l.
auid also ha.s weavker nodes oni tile, Spirals of tle body Caribbean fossil and Recent species that are referred wh orl, pairI iciilarl oti t li base. C. mu i6iu flu1 Olssonl to Alarmrnuostoma are iiot typical of that sulbgenuis. (1922, p). 164, pl. 15, figs. 9, it0), froml tile middle The o])erculumrn of Turbo cluyswomuos andl Its close Mimocne of ( ost'a Rical, has aI lowe-r sp~ire, less inflated allies has marginal oblique nairow grooves separating Spire whorls, and ilnor widely spaced bitsal nodes. minutely granular bands, whereas the oj)Crcululhi of the(
The1 more linltedt Spire whorls and less angiflated Caribbean speCcies has a, more or less dlistin('t shallow
Uitmi liicaI border of (" O.~TM111urn difh'eren t iate it, fron min.iginal ledge and is faintly granular or smoothI. the liviIng C'. afuumn 1all (1889, p. 370, 1)1. 33, figs,,. Turbo (Marmarostoma) aff. T. castaneus Gmelin
1 0, 11')wic fuirt hernmore is twice as lag. The two
spcnes of C. suqyaavm u m ent ioned by DalI lin 1889 Plate 201, figure 10
still aore tle oIilY 1&ipeselt'at ives of thiat, species Ini the( Of I med InuII size, sculptutire tnilmellar. Early whorls collect ions of the 1'. S. .It ional i\ [lseuln: thle type bearing at con spicuous prac ticallv smooth basal spiral. (dredge'd it a depthI of 120 talthiois 20 miles southeast La terl' whorls weakly shouldered, sculptured with of ("'ape hjIatt eras and la bod\-whorl fragmen1clt fronit, i noded slpirals. Somewhat worn operculuim assumed dept ii of' 107 fatlIionts 36 imies son t i of ( afwe Haitteras. to represent t his species Is smooth, bearing a poorly
O ccurrence : i\ Iidde plarit, of GJ'a tln foria t ion middlee defined shallow marginal ledge.
iN ocene) eaisterui areai, localities 155, 1 55c. i-height, (nlot (julit e comp~let e) 20.5 m1m1, (diameter
Famil TURBNIDAE(inconiplete) IS~ nun (figured specimen). Genu Tubo Lnn6An inicomplet e apparently ininatunre shell and( assoGens urb ~cia ted opercuium fromt thle middle part of the Gatunl
I iu li, 8%s etna liat tirze, e(1. 10, 1). 76 1, 1758. fornia tion antd a miold of a few w hiou'ls from tie( Toro Tvpe (tugut lpe, MoTntfourt, Conchllgie svist CUat i([1l, v. 2, finest one member of' the ( 'iagres sandstone are identi1. 203:, I1(): Tulrin, 1wholalti (TJudo iu hu01uitii Liniii lied ats Turbo aMl. '' un. They miay, in fact,
Perld,11-picl wsten Pcifc ad 11din (ceas. epr'esenit, die Rcent 0t(riibbeaii T. 'cuslaui Tfhe
Subgenus Marmarostoma Swainson olpel'(ulmIn fit tedl into at shell conlsleral)lvy larger than
j-(I, Zuulogita ii i atju ins, 2ud sem., v. 1, tox acopa thli only shell collected ait tilie sanlie localit\ .
in( pl. I I (tiimiii) rmd& I 52 The t\vpical formn of TI. cus/au us, as, long accepted,
I)( p7'111u4)t,:'I rbu /r!;OstolumiU116 Ro''1t tropical is sculpturledl wit Ii lioliiliielhi i nodled Sp~irals. Recent w esicrit P'meitie. Caril )eal Iiells tha t, have uiodedI spirals but, also hiave
NV\lvit S\\ a iiisoii lptol ose II tile gen eiric Ii tiil AbIiriuu- thI in lanella e forming va tilt ed scales on the( primary juN/u Ii, lie desiginito T urbo citrysoslotwo us s tite type. sIiral att lile shoulder, or' onl tlat, Spiral anld others, TI ic on] \iv Speces of Ab furo,tornw, I owev-et, (Iesc'ihled havxe been r'eferired to T'. en i luilous, also uiamned by bY Ii-j inat t Iia ti rue, 311. un i/u/u/ul (co t'Iec t l 11. 1/11- (inielin. T. crulu/t us fias tie( stiniW geogi'aplice range


as T. castan eus (Northi Carolina to the West JIndies), Type (logotyVpe, Grayv, Zool. 'Soc. London Proc., p. I-11, Is 17}: but is said to be more common at slightly shallower Turbo pullas (Tuirbo pullis JLin6), Rece.nt, NMediierriantan.
(lepthis (Dali, 1890-1903, pt. 2, p. :382, 1892). It, has (Gray' cited the generic inme asTrieolea.) been considered at synonynm of T. caste fl( u, a variety Before thle generic name Tr icolia' ciIn be 1used it I'l of castan es, or a valid species. The collections of the nleCcssaryI to dispose Of Laliarck's name Iltasialt 1/at U. S. National Museum indicate that the two form,, (1804, p. 295). Ihoughi1 that, name appeared in it pullintergrade. The ar*osdered forms Of a variable licationl onl fossils from the viciuiitv of Paris and twvo species, at least, until more is known about t heir habitat Eocene species alre the only ones that were described, and habits. Lamarck stated t hat lie was naming thle gnuws for a
The fossils from Paiiamni are nonilamnellar. They are Recent shell, ''fiisan (Deinu~)' ~spit e Launarck's not as strongly shouldered as most Recent shiells-that clear intenition and althoughi there is no doubt, about is, the spiral at the shoulder is not ais strong-and the the identificaitioni of the shell hie ment~lioned anid pilrtlY nodes on the sutural spiral, particularly oin the specimen described, hie cited no references that could be used ill from the Gatuin formation, are not, as coarse as those of fixing its Latin inme. Tre~~.fore( thle view that faistan, most Recent shells. InI both features, however, at fewv (- Ihccinutn a ast,'ali. Giieliii) Is the type by original Recent shells closely approach the fossils, designation (Woodring, 1928, 1). 418, 419, footniote) is
Other fossils suggest that Turbo castaiweuts was living hardly admissible. I amn indebted to 11. -A. ltehider for in the Miocene Caribbean Sea. A small incomplete pointing out that the (leticieiicy inl L-amarek's treatunelrt,
strongly shouldered lamnellar specimen from the middle was rectified within the next year by Roiss,7,'v (1805 or Miocene Bowden formation of Jamiaica is recorded as 106 p). 330), when lie, wrote ''Le type, (IC (c nouveau Turbo (Seneclus) species (Woodring, 1928, p. 41 1). A genre, (fue Ion1 doit enlcore a M. de L-aiarck, est iiiie strongly shouldered nonlarnellar form, Turbo (Steta) jolie coqiile alpleleefaisaii, H .'le stated thait this cf. caslan eus (Rutsch, 1934, p. 40,1)1. 1, figs. 1, 2) occurs spce isfo e oln nlo h e t5g
in the late Miocene Punta Gavildii formation of Vene- described it as IPhasianelloa rairb (/~a citing Buccima zuela. Turbo creaulatoides Nfaurv (1917, p. 153, pl. t,'itolnis Cheminitz in synionviny. This is aln ~equlivoc'al 24, fig. 14), from the middle MNiocene Cercado and type (designation and it is irrelevant that Lamiarck used'( Gurabo formations of the Dominican Republic, is only a vernacular namne for thle type sp~ecies. The type(, sculptured -with strong lamellae that extend from sut tire of Pitaiaielbi therefore is 1'. va,'mu,,ata Roissv (=Buicto base on the body whorl. It is doubtful, however, cimiimi ausiralis Gmnelin). Roissvx's- action fortunately whether it can be differentiated from stronglylmnla saves the traditional usage of Phasia ne/la. Recent shells.
Late Miocene deposits in western Florida yielded a Tricolia calypta Woodring, n. sp.
strongly shouldered Turbo bearing a few lamellac onl Plate 15, fjiurc 1, 2
spirals below the shoulder onl the later part of the body O lelilszIidrtl 1faesieh-1
whorl. It was recorded as Turbo caslatnes var. creiui- O eim szmolrtl nltd pr ih
lalus (Mansfield, 1930, p. 127, 1)1. 19, fig. 5). T'. casio'- Ctiuellar lip anid larietol callus thini. Umnbilical neus and 7. castatieas var. c,'enlalus are recorded from groove narrow. TyNpe showing cur-ved st idvl ref raethe Pliocene Caloosahlatchie formation of Florida.tebadona ciprtflod\lir,1nsstnig
Occurrence: Middle part of Gatuin formation middlee ouinsiimrlifiihes ew tat edndoMiocene), eastern area, locality 1551b. Toro limestone imlerclui lI ukmaorii in. n ebe olrImns
member of Cliagres sandstone, earlyy Pliocene), locali t \ )ecuu nkon 196. hleighit 4.8 mnin, diaineter 8.1 inun (typ~e).
When the family iine Tricoliidae was uised ini 1928 Ty'\pe locenlitv: 40a t(S26,S:-', Vamnos am off ol (Woodring, 1928, p. 418), it, was not intendIed as a new P'alenlla11. 1Poii, ( aal1 Zonle, ]I(\w slhiei'ged nltiiu name,11. It was used under thle impression that thle nam1,1e mneml ir of B1ol do() fonna I iou01. had been proposed or suggested: evident ly the result ne1~ oiart I, an ilt iouin 1a i ciit at- 01)( in Of
of anl erroneous i t el)retatiloll, p)ei'laps of Iredlae's I1ill's collect ions l'oi \iiilrios Vamnlos, alld t wo ol li'-, (1924, p. 232) statement. At aill events the name Is' to are II I MacD)oni 1 m Vatugi ciii> collect iiui fri tur iiw be supp~ressedl, for Tr'icolia atppeatrs to be properly ire- s-tine localit v. I'lie tYpe is tHie Only 'pecileii thal ferred to the fam-ily Phasianellidac. shows the retr-act ive hanlds.
Genus Tricolia Risso Thie whorls of 7r'Pco/ia cal!;p/i, are le- s coiisiricter I t
Itisso, Histoire iaturelle des 1)rineil)Alt's product ions de t I suitur di ian i hose of 1'. pH c orw( )Dall '1 91 5,P
I 'Europe nn6nidionale, v. 4, p. 122, 1826. 94, 1)1. 12, fig. 5), and the ,pecies front Pa nanii i it,


narrONOwI, 11U1hliCal groove. 7'. precamr~o occuris in the Family NERITIDAE
(et ir Vi\ ilocene( Tampa limestone of Fllor~ida. Subfamily NERITINAE
II i Europe Irielia( is recogn11-ized in strata. ,is old as Genus Velates Montfort
Paileocenie, hilt7 I. cal~pta, is thle, earliest, Anierican species MitrCnhliogess&natiqje, v. 2,1p. 355, 1810. so far described. Type (orthotyvpe): T-lae hic. ofloidr (Nerita, ronoidea LamiarckOccu rrence: i\ Jarine mi embler of Bol io (?) formation Ncrifii pui' ,rsa Ginelfii), Eocene, Pairis Basi.
(late EoceneI or eryOigocene), (3atnn La1ke area, Velates perversus (Gmelin), subspecies?
localities 40a, 40d. Plate 14, figures 5-8

Family PHASIANELLIDAE? Reaching a large size, Ovid in ventral plan, apex
Tricolia? syntoma Woodring, ni. sp. moderately eccentric. Coluinellar lip bearing seven or
Mak 1, igire47eight teeth. Callus deeply indented adjoining loe
1'L~ 17,figue IJendl of coluniellar lip and extending along inner border Smal"ll, Strongly Inflated, Sp)ire low, outline like that of outer lip, forming a wide rim.
of a minu11te na"ticid. Cohunllell'ar lip wide, its outer Approximate height 60 turn, restored diameter 100
edebeating a faint low narrow rim. Parietal callus mim (largest specimen). Height 22.5 mlin, diameter thick, cointinulous withl the coluimellar 11ip, its edg-e 43.7 mmn (larger figured specimen). sli arply defined. Unlitr lica~l groove ver-Y nar1row, 'alilost Th ough Veclate's was found in limestone of the Ciattunchised. Operculiuni unknown. cillo formation at five localities, the only specimens
H cidit 2.2 mmn, dianieter 2.2 rm (type). showing the aperture are from locality 38 in the Rio
Type)(: UISNM1 561,328. Casava area. The shell of medium size shown on
ljw loality 170'a (USGS 8411, headwaters of plate 14, figures 5, 7 is the largest, of 18 collected at Quebr-nada ('a)Im (Rio Caftn Quebrado), Panainn, middle that locality. Twvelve of the 18 have complete colporlt of (iat tin form at ion. uniellar lips, and onl 9 the outer lip is preserved. The
The family and generic assigmninent of this minute Shells from locality 3S, and l te incomplete specimens
spec(ies, represented by One specUien fromt tire middle from- the other localities so far as they are preserved, part- of tihe (latun formation, are doubt ful. Sonicl closely resemble Lutetian Paris Basin specimens of features suggest a low-spired Lricoliat but, 110 species Vdlats percrsus (for citations and synonymy see of Iiicolia exaniie(I has a ANide-rimlinied columnellar lip). Dimes, 1952, p. 12). Trhe fossils from Panaiuti that The' I Vlpo 111( only\ specimuen of ''L' ia' lirida Dali show tile outer lip, however, have a wide rim along (1897, p. 15, 1)1. 1, fig,. 11) Inl the collection of the U. S. the inner border of the lip, whereas the rim is absent Nat ionral M iseuni (a Recent shell from Britishi Coltint- oil 10 Paris Basin shells ranging in diameter from three bi'l) ha'Is a wide disi ci ly ii led columiellar lip, which to 70 millimeters.
I,,imt stm\n i the poorly drawn aperture of Dali's Khat heirlni V. WV. Pilfller ils kinly alleyatn
ill1st rat loll. T11ins Species, however, Is probably a tioli to the, Illustrations, of V. imikanic as .Bontscheff Ilowlupoina1 related to JI. &wbobsolchon (WiIllet t) (1937, (1896 [1897], p). 3180, p1. 6, fg. 1- -5), based on specimens p). W), pl. 25). '-\l ost species of Tl-iia have a thini from tire Eocene of Bulgariai. The Illustra tionis show parietall callus t hat fades ouit Oil the ]ailAl all. a rim onl the outeri lip like, that oii tire speimens from Neverti irless somue species have amioderatelyv thick I('ali~inia. Bout scheT (1896 [18971, T). 380, 1)1. 6, fig. 6) callu1s thlat 'Ins tie coltiumellar lip. Despite .ltits rela- also described a variety (V. ba/kao 'eas iagntu)for
ivl narrowx aplert ure, I rico/ia? ,q ntut mafy rep~re- Sp~ecniens onl which the thin edge of tile ou1teci lip 5crit, all 1 irdescri I ed tur ibinlid genus remnotecly related to extends around thre cnt ire aipertulre, bordering the callus. lluna/upuma. The t cet It of the Bulgarian. fossils tire heavier than those
III ouitline 'Iricolia? Sytdolwla suggests the M Iiocene of Specimens from Paiui. It, is dloub~t ful whether Ia irunca11 iiSpecies 7'Ii/b (Ft/ithidliun ) hadra Wood- the imi on the( ouiter lip is ill indicatilonl of (close relationrin~g (1 928, p). 420, pl. '4, figs. 10, 11) and a, minute ship Receni t ( 'mu barr ir/,i0 descr'ibed byv DalI (1889, p). 351, Vehues linrs a range of Laite Cret aceous to late Eocene.
t.1,fig. ]()b) aS ''P/iasiaiu jp1/a (I'uicousniia)' brt'cis V jpcrrcrs, is widely (list ribu ted in Etocene deposits d 'Orhigrrv., Boh pecies however, 1148Ve T1'icu1ia1-iike from Jild~ia tO the '-\edie'i'na region and the Paris aperti ural features. Baisin, reaching its acmie iii the midldle Eocene. The
Occur rrence: \ I iddle part, of (intuit format ion (mIid- genus is i'ehrt ively ri'am' in the American Eocene. Under dile M iocene), westerii anr'ca, locality 1 70a. the naie 1'-. ,sch/ti idciana, 1'. pi rrersas is recorded from


the Yellow Limestone of Jamaica (Trechmann, 1923, Vitta. According to Baker, in the publication just
p. 347, pl. 15, figs. 1-3). A similar, if not identical, cited, Vitta is estuarine to fresh-water and is found in form (Trechmann, 1929, p. 490, pl. 18, figs. 19a, b) and eastern America and western Africa. an unidentified species (Trechmann, 1924, p. 10, pl. 1,
fig. 7) have been found in other Eocene strata of that Neritina (Vitta?) species
island. Fossils from California have been referred to Small, spire worn. Callus thick, moderately convex.
V. perversus (Vokes, 1935, p. 382, pl. 25, figs. 1, 3, 5, Columellar lip finely and weakly denticulate. Color pl. 26, fig. 1) and to a species of doubtful validity, V. pattern poorly preserved, consisting of dark wavy axial californicus Vokes (1935, p. 384, pl. 26, figs. 3-8. A lines. Florida locality yielded a large Velates, possibly a large Height (practically complete) 7 mm, diameter (inform of V. perversus, described as V. floridanus Richards complete) 6 mm. Height (practically complete) 5 mm, (1946; Richards and Palmer, 1953, p. 13, pl. 1, figs. diameter (practically complete) 5 mm. 6-9). V. vokesi Cooke (1946; 1919, p. 126, pl. 5, figs. This unidentified VNeritina is represented by four 7, 8), from the middle Eocene of the island of St. incomplete specimens from the Culebra formation at
Bartholomew, is represented by poorly preserved locality 108c. The columellar lip is exposed on only
specimens, none of which shows the aperture. The one of them. The smallest has traces of dark axial
apex of V. vokesi is almost marginal, like that of V. lines and another shows such lines on a remnant of the noetlingi Cossmann and Pissarro (Cox, 1931, p. 37). outer calcite shell layer adjoining the edge of the callus.
The groove on the large specimen of V. vokesi figured This Culebra species, like the following Gatun species, by Cooke and also on the small figured specimen, may be allied to the Recent Caribbean ATritina virginea
which is the type, evidently marks the boundary be- (Linn6). It has a thicker callus than small specimens tween the area where growth takes place by addition of that Recent species. to the outer lip and the area where growth is the result Occurrence: Culebra formation (early Miocene). of resorption of the callus. The boundary between Gaillard Cut, locality 108c.
these two areas on the opposite side of the shell is not
apparent. A species of Velates, similar in outline to V. Neritina (Vitta?) cf. N. virginea (Linn)
vokesi, is found in limestone of middle(?) Eocene age in the Plate 21, figures 1, 2
Sierra de Bahoruco of the Dominican Republic, and Small, spire corroded. Callus moderately thick,
in deposits of probable middle Eocene age in Chiriqui strongly convex. Columellar lip finely and weakly Province, Panama and Baja California. denticulate. Color pattern consisting of closely spaced
The remarkable architecture of Velates was described minutely zigzag dark axial lines, wider at forward many years ago by Woodward (1892). apex of V's (apex toward outer lip). Near outer lip
Occurrence: Gatuncillo formation (middle and late and also near callus the widened apices disintegrate Eocene), Madden basin, localities 6, 7, 9, 15; Rio into isolated triangles. On later half of body whorl a
Casaya area, locality 38. solid relatively wide dark spiral band adjoins suture.
Genus Neritina Lamarck Height (incomplete, spire corroded) 3.6 nmn, diameter
Lamarck, Encyclop6die m~thodique, Histoire naturelle des vers, 3.6 mmi (figured specimen).
v. 3, pl. 455; Liste, p. 11, 1816. Two small shells, collected from the middle part of
Type (logotype, Children, Lamarck's Genera of shells, p. 111, the Gatun formation at two localities in the western
1823): Neritina pdulligera (Nerita pulligera Limnnd), Recent, area, are referred to Nerilina of. N. virgilea (Linn'). rivers of India and Melanesia. The color pattern is well preserved on the figured
Opinion 119 of the International Commission on specimen. On the other, slightly larger, specimen only
Zoological Nomenclature, issued in 1931, placed small patches of the outer calcite layer, and therefore
Neritina Lamarck, with N. pulligera as the type, in of the color lines, remain. The lines evidently are not
the Official List of Generic Names. as closely spaced as on the figured specimen.
Subgenus Vitta Mdrch The convex callus and color pattern suggest reletionM6rch, Catalogus conchyliorum * Comes de Yoldi, pt. 1, ship to the Caribbean Recent N. vrrgi;ea, which p. 166, 1852. reaches a much larger size. The most common color
Type (logotype, Baker, Acad. Nat. Sci. Phila. Proc., v. 75, p. pattern of N. virginea consists of wavy dark lines
137, 1923): Nerita virginea Linn6, Recent, southern Florida interrupted by dark-bordered ovoid or triangular lightto northern South America, mainly estuarine. colored eyes. The eyes are absent on some specimens
The convex callus and color pattern suggest that the and in some subspecies, but on Recent shells that lack following two species may be allied to Neritina virginea. eyes the lines are not as strongly zigzagged as on the They therefore are doubtfully assigned to the subgenus figured fossil from Panami. A specimen collected at


lie typ~e loc(alityV of A( rilina (Pa perita) _figulopicla spire whorls. The spirals, however, are narrow an(I the .Nlattry (1917, 1). 152, pl. 24, flg. 10; Coedo formation, posterior one does not adljoin the suture. Doiii han Re(pulblie) presumably (*olspecific with NiA. Occurrence: Gat uncillo format ion (middle Eocene), fildop~eta, has thle callus andl the prevailing color Rio Casaya area, locality 38. pattern of A. ivtryiii a and] evidently belongs to tihat Family LITTORINIDAE
Sp~ecies. GnsLtoiaFrsa
Tbe fossils fromt the Cattin format ion, and also those GnsLtoiaFrsa
fro m the C ulebra format ion referred to Arilint sp. F6riissaic, Talecaulx syst~inatiq ues dles aniaux nifullutis,
njybe ininiature shells of species is large as A. 1). -NI (vernacular name ''littoriiic' for ''paludines mariness',
flaY I ''five species of which are listedi Ov p. ix-x with the designation
uirgidtw, or may be muntlre shells of sinall species. As ''Pal uditta, marinee'', p. XXXIV lj'Littorine, Litto,'ina" as showni b unrous specimen-,, A. ek ipolana 1)all subgenus of "Paludiiie, Pal uditia, F6russ. (fluv. et muarn)",
(1890n-190:3, p)t. 2, p. 422, pl. 23, fig. 19, 1892), fromt no species mentionedd, 1822. the Chipola, format ion of Florida,, is at small species Type (logotype, de Blainvitle, Dictiunnaire des sciences (height 5 millimeters) comparable in size to the fossils naturelles, v. 56, p. 98 ('CA ganre Litturint', ayant pour type le T. littorcus"), 1828: Turbo littorcus Linii6, Recent, western
from Panamai. It, has a., color pattern of widely spaced], Europe. irregularly curved or zigzag, axial lines, or widely F~russae gave o dfinitio of tenm itrn n
spaced groups of two to five such lines. The callus is c'it ed 1opeie nocei t.On other pames hdowr, hie thinnier than that, of the fossils from Panami and is listed five species as marine species of IPaliudina and on ind~enited b~y at ledge adijoininig the base of the columellar still another page lie stated that, bie was forming a sublip. e~e: Iidelat fG uifrmto mdl genus under tie name littoriiie for marine paludines,
Mcene western par lofats ni o I 70a.e which constituted the genus Truclois of Adanson.
AiiomuQ wesernarea loa~liies161c 17a.ihese vernacular names are the same as those used onl Faily THIARIDAF? page X 1Vwith the correspond(1ing formal names.
Genus Hannatoma Ohsson? This is at rounidabout mnethodl, involving vernacular
Olss~on, Bull. Ani. Paleontology, v. 17, nio. 63, p. 80, 1931. names of determining what species F6,russac included Type (. tlutvope) : 3h'lanatriu? qcstc i Hlannia and Israolskv, Under Lillorina.
Cligut'eii, Perd. Littorina aff. 1. angulifera (Lamarck)
Hannatoma? cf. H. emendorferi Olsson Plate 16, figures 1, 2
Plate 14, figure 3 Of miediumii size, high-spired. Periphery of body
(Of sillwIll size for gemius Han naluina, Me1 alia-like in whorl sharply angulat ed at, beginning of whorl, obtusely outline. Preserved spire whors precalig penuilt scuip- anigulated toward outer lip. Narrowv spiral grooves I ured NvithI two stroiig flangelike spirals, the lost erior visile on lpreservedl parts of outeri shell. Coluniellar spral adjoning thle suture, the aniterior' spiral lying a lip exca vat ed. it tie iii front of middle of whorl. Peniult b earing also Height (practically coiplet e) 12 nuni dianeter 8.5 at n arr(ower spiral einergiiig from ant erior sut nrc. Body mum (figured specitnen). whorl 1 aokem i; a pertuore aid growth Ii ine uniknown. An imperb'ct spec-imen of thle genus Littiu'a was
itgh t (ii coiilet e) 3.5 mmn, (1iameter'I (i I(onlJplet e) found in, th e uppermost part, of lie Cumlebra format ion 1 5 mmi (figured specilneli). iii all a ssociafIioni of braddkih-walter aiid mna rhe species.
An incmihleti' siiled fossil fromt ft(e (lxatunciilo Awlel of the shell is not preserved, including time edge foriation ini the RIM ( asay a area is doubtful"y ilemiti- of t'e basal and outer lips. TIhe( scullptur'e, however, liedI as it species of lieu nalou~w t'omlaralble to I. remains Onl two p~atches ol outer shell. It sosto best uu ,'1d/l'fir7, w ili occuirs ill W le floweie of l~eru, in advantage on the hase of the body Yliol adkoinng the vrai t t hai werie t lioiigit to beofo(ligoenie age when thle t hini wash of p~arietal callus. species was tle'sriln'd ( )lsoii, 1921, p. Q2 1)d. 15, ligs. Inipefee as I him fossil is, Ai i4 of t'xeeiomwi inWrest, 2, A Wnoit iual e thIle alt'itv iIs t priserveti and as it is the first Twi'ti'ir Liffbui'u W hle recorded front thle growvt iiln is iiot, thiset'rinie. be' spirals are thle ( amildhmeiti re'gioni andh it ext t'iil back to the' eai'ly nior flligelil~vth lani tis hof0 /f. uniiht iai'/ and of at Nlio('t'ii e Iiliuieane of at living (Cariblbeani species, L. closcl. ai~ieth, or itliilo foriii founI hii sw aa of late "nguiljr" ia aiiarek) (Wel-1t't, H13 In 23 0 ~. 7).
F aWsk,11 e( inl ceterui ( oloiiibia' antd ux sterii Venezuela. rTe fossil so t'losely rest'nibles small niflhoiltt( 51)e(itoie slowies of I1'alt', iriluliig Al'o'ui' of It'e w itley nuins o~f L. uil7 that uinequivocail iissig-iuuiiti to dimteid Fel':t '1i fii /;(eha (1,antartl\) Q( x, 11930, that sptecites iia\ Ibe just ifiedl. The t'ounut'lr lip is pt 157, I 1)1 I figs, 2, 2) ive Nto flanigelikt' spirals onl Nviter thlain ml most Smill Shetlls of L. antpd'il e x-


amined, but on some small shells of the Recent species Olsson, 1941, p. 47). As a matter of fact, it has it is as wide or wider, become evident that both statements are juiistified
According to Bequaert (1943, p. 24), in his recent (Pilsbry and Olsson, 1945-52, p. 38, 1952). The typical monograph of the western Atlantic species of the form of the type species, kiiownii only from Art hiur
genus, L. angulifera is found, generally on mangroves Adams' descriptions and illustrations, reproduced 1by in brackish inlets, from Florida to Brazil, on the west Pilsbry and Olsson (1945-52, p. 251, pl. 22, fig. 6. 1945; coast of Africa, and has reached the Pacific coast of p. 38, pl. 2, figs. 1, la, 1), 1952), has an exposed spire. Panami by transportation through the Pananni Canal. A form from the Gulf of California, so similar in essenThis species is recorded from Pleistocene deposits on tial features to T. politum that it was described as T. the Caribbean side of the Canal Zone near Mount Hope politum ultimum (Pilsbry and Olsson, 1943-52, p. 252, (Brown and Pilsbry 1913a, p. 495). It is represented pl. 22, figs. 1, la, lb, 1945), has a concealed spire. In in three of MacDonald's Pleistocene collections from other words, the subgenus Idioraphel, which has a conthat area (USGS 5849, 5850, 5868) and also in two lots cealed spire, is not as sharply set off as it was once of Pleistocene fossils lie collected at and near the north thought to be. Idioraphle also resembles 7t.notoma end of Gatun Locks (USGS 5867, 6038). s.s. in having a thick shell, thick calblus. and thick
After this report was in proof a small imperfect enamel. Nevertheless Idioraphe is a useful name for
specimen that seems to be L. angulifera was found in small teinostomies that have a concealedd spire, are not a collection from strata of middle Miocene age on Rio strongly depressed, and lack the spoutlike extension of Banana in southeastern Costa Rica (USGS 5882f) the peristome characteristic of T. poli tum.
and a large specimen, unequivocally identified as that
s Teinostoma (Idioraphe) spermatia Woodring, n. sp.
species, was found in a collection of late Miocene
fossils from Swan Cay, in the Bocas del Toro Archi- Plate 17, figures 19-21, 31-33, 37-39
pelago, northwestern Panami (USGS 8305). ?Tcinostoma of. carinalum d'Orb., Toula, K. k. Geol. RtcichsanBequaert (1943, p. 3) assigned L. angulifera to the stalt Jahrb., Band 61, p. 497, pl. 31. fig. 10, 1911 (M\iocene, subl)genus Littoraria. Canal Zone).
Occurrence: Uppermost part of Culebra formation Small, thick-shelled, depressed but somewhat dome(early Miocene), Gaillard Cut, locality 110. shaped. Periphery bluntly angular oni early part of
body whorl, narrowly rounded on later part. Tip of
spire exposed, remainder concealed by overlap of body
Studies of Recent vitrinellids have not yet progressed whorl. Entire spire concealed by enamel on very large far enough to sort the genera of probably diverse affin- specimens. Umbilical and parietal callus thick and ities that are currently placed in this family. The completely coalesced. Gatun formation yielded all the vitrinellids described in Height 0.7 mm, diameter 1.8 mm (type): height 1.1 the present report. mm, diameter 2.6 mm (large form, figured).
Genus Teinostoma H. and A. Adams Type: USNM 561312; paratypes, Stanford Univ.
H. and A. Adams, Genera of Recent Mollusca, v. 1, p1. 122, Type locality: 147b (USGS 6033c, Panama Railroad, August, 1853. about 3,500 feet (1,065 in) southeast of Gatun railroad
Type (virtual monotype and logotype, A. Adams, Thesaurus station, Canal Zone), middle part of Gatun formation. conchyliorum, pt. 22, p. 259, 1863): Teinostoma politumo A. Teinostoma Speraia is the most wiespea teioAdams, Recent, Santa Elena (presumably Ecuador). Teosom spermaia is the most widespread teinostome in the middle part of the Gatui formation and is
Pilsbrv and McGinty (1945-50, pt. 1, 1). 1, 1945) particularly abundant at the type locality, where have pointed out that Teinosloma was virtually mono- several hundred el)cimms were collected. It is reptypic, as T. anomalum C. B. Adams, the only species resented, however, by only one specimen from the
mentioned other than T. polituim, was a nude name.
U pper part of the formation, and none was found in the
No known Caribbean fossil species has the characters lower part. of the subgenus Teinosloma s.s.: greatly depressed shell
I sImmature shells (pl. 17, figs. 22-24) are more nearly and spoutlike extension of the peristome.
circular than mature shells. Furthermore the outer
Subgenus Idioraphe Pilsbry lip of immature shells ascends almost to the tip of the
Pilsbry, Acad. Nat. Sci. Phila. Proc., v. 73, p. 398, 1922. spire and therefore has a different outline from that of Type (orthotype): Teinostomna angulatum (Gabb) (Cyclops mature shells. Three specimens from the type locality, angulatus Gabb), Miocene, Dominican Republic. one of which is illustrated (pl. 17, figs. 19-21), show
It has been claimed that the spire of Teinostloma s.s. faint to fairly strong microscopically pulnctate spiral is concealed by overlap of the body whorl (Woodring, striae. This sculpture is doubtless a normal character, 1928, p. 444) and that it is not concealed (Pilsbry and but is ordinarily concealed by enamel. The three


specimens that show it have thin enamel, except on the Type locality: 137 (USGS 16911, Transisthmian later part of the body whorl, where the sculpture grad- Highway, 1.7 km northwest of Sabanita, PanamliA), ually disappears under the thicker coat of enamel. lower part of Gatun formation. Fourteen specimens from the type locality that are This teinostome, found in the lower part of the Gatun assigned to T. spermatia are exceptionally large as com- formation, is considered a small race of T. angulatum pared with scores of apparently mature specimens, like (Gabb), the type of Idioraphe, from the Miocene of the the type. As shown on plate 17, figure 31, the tip of Dominican Republic (Pilsbry, 1922, p. 398, pl. 37, figs. the spire of this relatively large form is covered with a 1, la, lb). Gabb's specimens were collected at an unthin glaze of enamel. These 14 large specimens, which known locality in the Dominican Republic. Specimens do not intergrade with the much more abundant from the Cercado formation-Maury's T. sandomingense
smaller apparently also mature form, may represent a (Maury, 1917, p. 156, pl. 24, fig. 24)-evidently are different species. If so, however, immature shells of conspecific, although the early part of the body whorl the large and the small species have not been distin- of the type has a more sharply angulated periphery. guished and apparently are indistinguishable. T. angulatum trochalum is smaller and lacks spiral
Species more or less closely resembling Teinostoma sculpture. T. umnbilicatum (Lea) (Mansfield, 1930, p. spermatia have been living in American waters since 134, pl. 20, figs. 1-3) and other Tertiary species from Eocene time. The very similar T. tecti.spira (Pilsbry, southeastern United States, as well as the Recent T. in Olsson and Harbison, 1953, p. 417, pl. 50, figs. 6-6c), cryptospira (Verrill), have a less angular periphery. a Pliocene species from Florida, has no trace of spiral Occurrence: Lower part of Gatun formation (middle sculpture. T. spermatia is more depressed and more Miocene), localities 136a, 137, 138a. elongate in dorsal outline than T. angulatum (Gabb) Subgenus Aepystoma Woodring, n. subgen.
I Z_ Subgenus Aepystoma Woodring, n. subgen. (Pilsbry, 1922, p. 398, pl. 37, figs. 1, la, lb), and even
(Pisby, 92, ). 98 p .7fis1,l,1),aden Type: Teinostonux (Aepystoma) andriant Woodring, n. sp., Mliothe large form of T. spermaia is a little smaller. T. Type: inosoma (Apysto) andrium Woodring, n. sp., Mio1 scene, Gatun formation, PanamAd and Canal Zone.
angulatum, which is found in the Cercado formation of cene, atun formation, Pana d Canal Zone. the Dominican Republic, has very faint closely spaced Of medium size, thick-shelled, spire moderately despiral striae. Species similar to T. spermatia are living pressed, exposed. Smooth or sculptured with punctate in both western Atlantic and eastern Pacific waters. fine spiral striae. Umbilical and parietal callus thick, T. cryptospira (Verrill) (Bush, 1897, p. 118, figs. 1, 2) more or less coalesced. Callus filling umbilicus on ranging from Cape Hatteras to Florida, is more circular mature shells. in dorsal outline. T. cecinella Dall (1919, p. 369), a The subgeneric name Acpystoma is proposed for a species from Lower California, is more elongate in group of thick-shelled teinostomes that have an exdorsal outline, larger, and has a thicker shell. posed spire and callus-filled umbilicus. Fossil and
Toula's T ioslomna cf. T. carinatm may be T. Recent Panamic species allied to Tidnostomna andrium spermatia, though his illustrations show an exposed have been assigned to the subgenus Pseudorotella by spire and a peripheral carina. Pilsbry (in Olsson and Pilsbry and Olsson. Pseudorotella, however, has a Harbison, 1953, p. 415), however, thought it is very smaller and thinner shell and less depressed spire. similar to the Recent T. carinatum (d'Orbigny). Teinostoma (Aepystoma) andrium Woodring, n. sp.
Occurrence: Middle and upper parts of Gatun formatO ( ide: in Middle r art (fatern rea, Plate 17, figures 40-42; plate 18, figures 9-11
tion riddlee Miocene). Middle part, eastern area,
localities 146, 147h, 147f, 147g, 147h, 147i (identifica- Of medium size, thick-shelled, dorsal surface slightly tion doubtful), 153a. Upper part, eastern area, (domled. Periphery rounded on later part of body whorl,
locality 177. faintly and bluntly angular on early part. Sculpture
of microscopically punctate faint spiral strike, for most
Teinostoma (Idioraphe) angulatum trochalum Woodring, n.l onby wo ft sp ec ns
subsp. part concealed on body whorl of mature specimens by
glaze of enamel. Umbilical and parietal callus thick
I'lato 17, figures 4-6 an coalescing.
and coalescing.
Small, moderatly depressed dome-shiaped. Periph- HIeight 2 nun, diameter 4.7 nn (type).
ery moderately angular on early part of body whorl, Type: UTSNM 561315; p)aratype, Stanford, Univ. roundedI on later partl. Spire partly concealed by over- Type locality: 137 (USGS 16911, Transisthmian lap of body whorl and glaze of enamel. Umbilical and Highway, 1.7 km northwest of Sabanita, PanamA), parietal callus lthick anid coalescing. lower part of (Gatun formation.
Ieight 1 ln, diameter (incomplete) 1.7 mm (type). Teinostoma andriumn is by far the largest of the Gatun Type: USNM 5614:31; paraty)es, Stanford Univ. teinostomes. The sclnture is distinct only on early


whorls. The umbilicus of immature shells is not corn- The faint sutural collar and narrow parietal callus pletely filled with callus (pl. 17, fig. 41). are characteristic features of Tifostoa pycilum. The
T. andrium is closely related to T. caroniense Maury few specimens from the Gatun formation are slightly (1925, p. 249, pl. 43, figs. 3, 4), a late Miocene species smaller than the type. T. itrn m (GCabb) (Pilsbry, from Trinidad, but has a flatter columellar lip and 1922, p. 399, pl. 37, figs. 3, 3a, 3b), from the Cercado flatter umbilical callus. The recent Ecuadorean T. formation of the Dominican Republic, lacks the faint millepunctatum Pilsbry and Olsson (1945-52, p. 253, sutural collar. T. parcicallfrm Pilsbry and McGint v pl. 23, figs. 1, la, lb, 1945) has more coarsely punctate (1945-50, pt. 1, p. 4, pl. 2, fig. 2, 1945), a Recent spirals, and is smaller and thinner. The Recent west- teinostome from Florida, is slightly larger and has a ern Panamic T. imperfectum Pilsbry and Olsson (1945- higher spire. 52, p. 254, pl. 22, figs. 2, 2a, 2b, 1945) also is smaller Occurrence: Lower and middle parts of Gatun and thinner, and has a thin, narrow umbilical callus. formation (middle Miocene). Lower part, locality 18:8.
fora-Middle part, eastern area, locality 147b. Bowden
Occurrence: Lower and middle parts of Gatun forna- Middle part, eastern area, locality 147. Bowen tion (middle Miocene). Lower part, locality 137. formation (middle ioene), anic. Middle part, eastern area, locality 147i. Teinostoma (Pseudorotella) stemonium Woodring, n. sp.
Subgenus Pseudorotella Fischer Plate 17, figures 1-3
Fischer, Jour. Conchyliologie, t. 6, p. 52, 1857..
Fischer, Jour. Conchyliologie, t. 6, p. 52, 1857 Small, moderately thick-shelled, periphery rounded,
Type (monotype): Pseudorotella semistriata (d'Orbigny) (Rodlla mar b rl th e o y o e
semistriata d'Orbigny), Recent, Cuba. but marked by a spiral thread. Body whorl somewhat
pinched against suture. Whorls smooth between
Pseudorotella is used in the present report for small, suture and periphery. Periphery and base near smooth or spirally sculptured teinostomes that have a periphery sculptured with four or five relatively heavy periphery sculptured with four or hive relatively heavy
moderately thick shell, exposed relatively high spire, spiral threads (three or four on immature shells). wide umbilical callus filling-or not quite filling- the Umbilical callus completely, or not quite completely, umbilicus, and narrow parietal callus. This usage may filling uml)ilicus. Parietal callus narrow, overlapping be found to be inappropriate when specimens of the umbilical callus. Junction of outer lip and parietal
type species are available. The type species has fine callus forming a faint gutter. spiral striae above the periphery, according to d'Or- Height 1 m diamnter 1.5 mm (ty ). b ll g iater .5 m (type).
bignys illustrations. Type: USNM 561432. Paratype, IUSNM 561433.
As suggested by Pilsbry and McGinty (1945-50, pt. Paratypes, Stanford Univ.
1, p. 2, 1945), subgeneric rank is preferable to the Type locality: 138a (Stanford Univ. locality 2656,
generic rank that has been assigned to Pse udorotella Transisthmian Highway 1.6 km northeast of Canal
(Woodring, 1928, p. 445). The Miocene Jamaican Zone boundary, Panami; same as USGS 16909), lower
"Pseudorotella" hownmala Woodring (1928, p. 447, pl. 38, part of Gatun formation. figs. 13-15) represents a minor group of teinostomes, This sculptured Ise ,ndoroldla is rel)resente(d by nine more closely related to Aepystomna than to Pseudorotla, specimens collected by T. F. Thompson from the lower characterized by a bicarinate truncated periphery and part of the Gatun formation. It seems to have no relatively strong spiral sculpture. known close allies.
Teinostoma (Pseudorotella) pynum (Woodring) Occurrence: Lower part of Gatun formation (middle Teinostomna (Pseudorotella) pyenuma (Woodring).
Plate 17, figures 25-27 iocene), locality 138a.
Plate 17, figures 25-27
Subgenus Diaerecallus Woodring, n. subgen.
Pseudorotella pycna Woodring, Carnegie Inst. Washington Pub. Subgenus Diaerecalus Woodring, n. subgen.
385, p. 446, pl. 38, figs. 10-12, 1928 (Miocene, Jamaica). Type: Tcinoma (Diarecallas) sychinm Woodring, n. sp.
Small, moderately thick-shelled, periphery rounded. Miocene, Gatun formation, Canal Zone.
Body whorl pinched against suture, producing a sug- Small, thick-shelled, smooth or practically smooth.
gestion of a sutural collar, corresponding to faint gutter Suture strongly impressed. Umbilicus filled with callus. between outer lip and parietal callus. Umbilical callus Edge of umbilical callus forming well defined ridge. thick, filling umbilicus. Parietal callus narrow, its Extension of parietal callus overlapping umbilical callus, edge sharply defined. deeply grooved adjoining columellar lip.
Height 0.8 mm, diameter 1.3 mm (figured specimen). Diacrecallus is characterized by the strongly impressed
Type: USNM 135502. suture and the abrupt overlap of a grooved extension
Type locality: Bowden, Jamaica, Bowden formation of the parietal callus. It may represent a modification
(middle Miocene). of Aepystona, or possibly of a teinostome more or less


similar to tile subtelills Altwil'icalho4 I"Isbry and radiata, no natter how unequivocal his intention proves McGintY (19.45-50, 14. 4, 1). 17, 194G; t ype (orthotype): to be. T(linostoloa cariMC(Ithis I'llsbrY and McGiiity, Recent,, The species of Aitticlimax have recently been reviewed Flonda). Aliwilicalhis has a, sharp ridge at the edge by Pilsbry and Olsson. The agents is strongly dortieA the umbiliral callus, whicli is CMICIIVO. shaped and has axial folds or undulations of var'Ying
streiigt1i on the base of the shell. The subgetius Teinostoma (Diaerecallus) sychnitm Woodring, n. sp. Aidictimax s. s. is characterized by a narrow callus on Pkiti 17, tigun 2 -30 the colulnellar 111), froni, which al ridge spirals tip the
,widely opeii unibilietis. The earliest species occurs in tliiek-slielle(l, per'plier.v rounded. Apical
the varIv Nliocene Thonionde formation of Haiti. A Nv I Iorl lal-ge for size of sliell. I-ei- v faint, microscopic Receiit, ., species is fomid in the Caribbean Sea and
-I)II-al trliae visible oil pemilt or earlier whorls of solne niodier possible \ off Florida, but, none
spVC1111011s. Villbillcal callus bollilded by ridge, NvIliell so far in tlie
PfIllaillIC, re"1011.
I', A)Verlapped bY extension of 1)arletal callu-. Extensioll of 1),li-jeta], Callus deep]v grooved adjoining outer 111).
r, Anticlimax (Anticlimax) gatunensis Pilsbry and Olsson
Ifelgilt, 1.1 111111, (11,111teter 1.7 111111 (tvpe). Ilei,_,ht
Plate IS, figures 5-7
l.G imil, diameter 2.2 mm (laro-est speelillell').
Tvpc: t-SNNI 561;)']G. Aoticlintax gabiocti-sis Pilsl)rv and Olsson, Bull. Ail-I. PaleontolI 'h, 1950 (Miocene,
33 No. 135, 1). 7, pl. 2, figs. 5, .5a, .5
Tvpo locally: 1,471) (USGt ) 60:1:1cl, Panama Rall oad n I
r Panallkq).
ahout, :1,5 1, 00 ft (1,06.5 111) soutlieast, of' (Tatim railroa(i Doint-diaped, base flatteiied. Peripheral carilia a statioll, atial Zolic), nii(ldle part, of Gntim formatloii.
relatlvelv xvide, tlilll ledov. Upper surface sculptaired 'I'lie curious callus, slio\vii bY four specimens froin the
IvI)e localitv, at first, glance su(1-vst,,,-; it)] iorilia lit N1. With AN-cak spiral striae, which disappear near periphery Tile extellsion of tlw palie a t a la e aiid oil upper surface of peripheral ledge are replaced
im -os -ads. Base bearing 13 1 eavy
"I'"W01 sta".e. It, Is oil diree 1111111ature shell", b.N ci copic axial tlir( Z, I
x1al folds. 011tcr half of base, including b1se of fi-om die tYI)e locatitY niid also oil ait sl I a
peripheral ledge, sculptured with spiral striae. Ridge fl-oll1locatitv 155n, Z,
Y. borderfli, umbilicus nioderatelv iiarrow. 'I'llese Immature sliell"-, resemble the sill)(Niltis Py- Z71
01 Height, 1.7 inin, dianieter (Incomplete) 3 min (figured
hIlt 11,1VO a Iow r*(1o.e at t1w ed e of tile Aillil)*lical callits. Vie laro-e apical wilorl alld illipresse(I
v of, tllis Sl)('('* wortllv features. _N I- les are ]lot(, Tvpe: Acad. -Nat. ;cl. Plilla. 18401.
vlose fossil or living alties are knoNvii. Type locallt.v: Cut oil Boyd-Roosevelt, (Transbelow bridge over Rio cativtt
Occill-l-ence: M iddle part, of (1,10111 forillatioll (Illiddle I- r,
and about .3"i llilles front road fictionn at Mar-arita, :Mlocene), oasterii arefl, localities 1471), 155a. I I L
Panama (saine as USGS 16909) lower part, of Gatlin Genus Anticlimax Pilsbry and McGinty formation.
Subgenus Anticlimax s.s. Tlie figured specimeii, a topot ype, has a damaged
hlshr v aiid N:mtiliis, v. 60, 1). 12, 1946. peristome aiAd eariiia. It, is div ol)l,\- specilnell III the
1'.v1w (kwoi v1w (Pikhr v tlld Nautilus, v. 59, 1). 7 7, U. S. Natioital Museum collections'; two smaller speci1916) Of 0hilacia Dall, 1903 (11ot, AI'l-tellhil, 1869), ronallied mens axe in the Stauford University collectimi froill the (Jitwicina Agmtvo ond Borro, 1946 (not C;eininellaro, 1878), saille locality. The flatteiied base and Nvide peripheral retlained Antirlitwix): Tcin,). Iolwl (Clholrio) twlliglypholt carill'a are flle niost (.11aracterisfie features, of this Dall, Plioc('tw, Flori(l i, species. These features distiii(mish it from the most
Perilaps All ticbtwix, the second 1wille pl-oposed ill elosely related species, A. ,wh?imo i (Vanatht) (1913, p. raj)id successioll as repIace'no', t, of tile lionionlyin 24, pl. 2, figs. 2, 7), a Reevia species froin British t"b*1w1c;(1, waS not, intended t)o be as densivo as it soulids. Honduras. 4. dorbyi (Nfatirv) (1917, 1). 156, 111. 24, 'It reealls some of Joussealillie's Imme's'. li,,. 20), the oidy other described Miocelle species of
Ttinostolna ((,7)*1n(1v *(1) C(d11*y1,ypt?1m, was -61.01,1111v tile Aldwlimax S.S., occurs ill die Cerea'do formation of Inollot vpe of' Oilnefc '(I. Dall Ilsed t1l"It collibillatioll ill the Dominican Republic mid in the Titonionde forniaIs J fossils and III Ow explallat'loll of a plate (Datt,
list, t I of Haiti. It, has a more swollvit base, narrower
1890 190: 14. G, 1). 1,610, 1,6:1:1, 190: )'). He also periplieral ledge, fewer mid licavler folds oil flie base, 11,ed ille Collibillatioll 71"I'llostoma (01,11mci(l) lwdiafil nild lio SI)iral striae oil the base. Dall III Ole saille list of fossils, 'I'lleiv is, Ilowever, no Occurrelive: Lower Ima, of Gatlin forniatioll (illiddle indicallon Illat, It(, 11dendcd tlult nallie for Ilis Collonia Mloveiie), localities 138, 13811.


Subgenus Subclimax Pilsbry and Olsson narrowver umbilical callus,and lacks the extended )periPilsbry and Olsson, Bull. Amn. Paleontology, v. 33, No. 135, p. 5, stome. A. willetti Hertlein and strong (1940 51, pt.
1950. 10, p. 112, pl. 9, figs. 13-15, 1951), from the Pacific
Type (orthotype): Anticlimax hispaniolensis Pilsbry and Olsson, coast of Costa Rica, is larger and has stronger basal
Miocene, Dominican Republic.cosofCsaRiaislrrrndhstxne bsl
Miocene, Dominican Republic. undulations. The only other recorded Miocene speci's
Subclimax, which is somewhat intermediate between of Subclimax, 1. hi.spaaidol i Pilshry and Olsson, has
Anticlimax s.s. and dome-shaped species of Tdrtostoma, a sunken apex and axial undulations on the upper has the umbilicus partly or completely closed by a surface of the body whorl. Both Gatun species of
wide umbilical callus. It has, however, axial undula- Anticlinax are more similar to Recent species than to
tions or folds of varying strength on the base, like those contemporaneous or slightly older Miocene species inII of Anticlimax s.s. The earliest species, occurring in the the Caribbean region so far described. early Miocene Baitoa formation of the Dominican Occurrence: Upper part of Gatun formation, western
Republic, is of the same age as the earliest species of area (late .Miocene), locality 185. Anticlimax s. s. Subclimax is living in the western
Atlantic and the eastern Pacific. Genus Cyclostremiscus Pilsbry and 01sson
Pilsbrv and Olsson. Acad. Nat. Sci. Phila. Proc., v. 97, p. 246,
Anticlimax (Subclimax) teleospira hystata Woodring, n. subsp, 1943.
Plate 18, figures 1-3 Type (orthotypc): Vitrineila panam i,s C. B. Adams, Recent,
Pacific coast of Pami.
Dome-shaped, base slightly inflated. Periphery Pacific coast of Pamzi.
bluntly angular, except near outer lip, where it is drawn Subgenus Ponocyclus Pilsbry
out into a ledge. Upper surface sculptured with faintly Pilsbry, Acad. Nat. Sci. Phila. Mon. 8, p. 426, 1933. punctate spiral striae, which are indistinct or absent Type (orthotype): Adeorbis b ii Fischer Recent, Florida and on middle third of body whorl and near outer lip. West Indies.
Base sculptured with faintly punctate spiral striae that Ponocyclus lacks the axial sculpture of the subgenus disappear near umbilical margin and toward aperture, Cyclostrmiscus s. s. Some species, however, are more
except on peripheral ledge. Base also bearing faint or less intermediate and Pilsbrv realized that the name
crude axial undulations. Umbilical callus filling um- Ponocyclus may eventually be found to be superfluous.
bilicus, except a narrow niche adjoining parietal callus.
Junction of outer and basal lips drawn out in an Cyclostremiscus (onocyclus) pentagonus (Gabb)
angular thickened spoutlike projection, broken on Plate 17, figures 7-15
type. Cyclostiremia pentagona Gabb, Am. Philos. Soc. Trans., n. ser.,
Height 1.5 mm, diameter (incomplete) 2.7 mm v. 15, p. 243, 1873 (Miocene, Dominican Republic).
(type). Vitrinella pentagona (Gabb), Gabb, Acad. Nat. Sci. Phila. Jour.,
Type: USNM 561319. 2d ser., v. 8, p. 368, pl. 47, fig. 68, 1881 (Miocene, Dominican
Type: loc y 59 Republic).
Type locality: 185 (USGS 8383, Caribbean coast, Cyclostrenia quadrilinceatumi Toula, K. k. Geol. Reichsanstalt west of Rio Miguel, station 26 plus 100 feet (30 min) Jahrb., Band 61, p. 497, pl. 31, figs. ll-c, 1911 (Miocene,
Panami), upper part of Gatun formation. Canal Zone).
Aticliax telospira hystata is represented by two Circulus pentagona (Gabb), Pilsbry, Acad. Nat. Sci. Phila. Proc.,
Anticlimax teleospira hystata is represented by two
v. 73, p. 397, 1922 (Miocene, Dominican Republic).
specimens from the upper part of the Gatun formation "Circdus" pentagonaus (Gabb), Woodring, Carnegie Inst. Washin the coastal area west of the Canal Zone. The spout- ington Pub. 383, p. 441, pl. 37, figs. 16-18, 1928 (Miocene,
like projection of the peristome is like the projection Jamaica).
of the type of Teinostoma. It is broken on the type Small, depressed, whorls 4/, the first 2/2 very slowly
but preserved on the other specimen, which is other- enlarging. Protoconch relatively large, rising abruptly.
wise less complete. A. telcospira proper (Pilsbry and Body whorl bicarinate or, less commonly, tricarinate.
Olsson, 1950, p. 10, pl. 2, figs. 7, 7a), which occurs in Early whorls rounded between sutures. A carina apthe lower part of the Gatun formation but is not pears on later half of penult about midway between
represented in the U. S. National Mfuseum collections, sutures and forms upper carina on body whorl. Basal has a carinate periphery and stronger basal undulations. carina generally weaker than upper. Periphery
The closely related A. tholus (Pilsbry and McGinty) rounded, bluntly angular (the usual condition), or (1945-50, pt. 3, p. 79, pl. 8, figs. 1, la, lb, 2, 2a, 1946), sharply angular, forming a third carina. A few specia Recent species from Florida, has stronger spiral sculp- mens have one or more faint spiral threads on penult ture and lacks the extended peristome. An unde- above carina, and a few have a low spiral thread on
scribed species, dredged at a depth of 6 to 9 fathoms body whorl below and near upper carina or above and off Beaufort, N. C., has a more angular periphery, near lower carina. Umbilical wall bearing crude gen-


c(idllY faint spir-al cords more or- less roughiened by that with the same number of whorls (about 41,) Recent (i-iowli tialas. Upper part of lperistoie gently shells are almost twice ais large. Recent shells and aticlied& loi'watrd. those from the Gatun forinatioii have the same kind of
I leiglit 1 11111, (1i1iaieter- I.6 nun (figured lbicaliflfte protocomich anid aperture. InlaSni1chI ais thle degree of sJpeClieill) t1lilt 1 .1 111111, (liilietet- 2.3 mili (figured eiflargemeint, is the only character 11ow apparent to 1,iege s1)eculieli d1ifferent iat e Recent, shells amnd( t ricaria t e fossils, tretT ,\-I(, Acad. Nat. Sci. 1Piihi 2. memit of "'C.'" trilix as a subspecies of C. p(IdUYoflus
Type locahit,\- v Iomiinican Republic, A'\ioclelie. appears to be lpreferailble. Fossils from the early
T1is; small ( yclos1rtmn ills occurs tlir-ougiloll L tbe Miocenie ChipolaI formation and the middle Miocene 6,1011n formation. It. is rare Ii die lower- pait, rare to Shoal River formation of Floridat have been referred to t iidaI'it InII tle middle part, and rare iii the tippet- ''Ctculux"' lrillr (Gardner, 1926-47, 1) 600, 1947). part Sever-al lniiidlredl slpecimnis were collected f-oni These Florida fossils are tricaritiate andl are larger
Ih ]l(l di par-t at locality 1471). thaii those fromt thle (latui formation.
thlese fossils si ow a1 considerable mange of vaiation ''( 'bcilus' ccrroscasi.s Bartschi (1907, p). 1,73, figs. 9a,
ill tile outline of tle body whorl1-, inl the1 l-eseiice, or 1), c), which ranges fromt Santa, Catainia Island, Calia absence of spir-al t Il reads near the upper and lower. form ia, to Baja, California and the Giulf of California,
calncand Ili tie 51 ieigtli and~ coar-seness of t lie spiral andl probably to PanlamlA, is tile eastern P~acific analog (or~ds facing tile tim)bilicus. Tile usual fortit is lbicar-i- of ''reut~'i~c. It has not beeni determined na,)te (p ,1. 17 figs. 7-9). Tlioiigli ticariate shells (p]. whv~ether Pacific andl Atlanitic, shells can consistecnt ly le 17, figs. 10- 12) ai-e not connon in thel middle par-t of distiniguishied. Relatively Strong spiral cords facing the ( at tin formation, the fewN specimnis from the lower the umibilicus are more common in the few lots of
anid ulper pai-ts (one and two respectively) are tri- Pacific shells. Shells fromt both oceans that are still (a 1 rmate. Spir'al t eads, generally faint, near the uip- lustrous show under strong light very faint microp~er and lower ca iliiae are1 eXce})t i al. The umbilical scopic spiral limneation It is doubtful whether (Cyclospil-als guerail3 ar~e Neak. The(y arec, however, ex- gsrc lcs bptmplialus Pilsbrv and Olsson (19435-, ceptiomlially str-ongc onl the large sp~ecimten shown on p). 67, pl. 7, fig. 3, 1932), a, Pleistocene form from the p~la te 17, fig1ures 1:))-15. This large specimen, collected Pacific, coasts of western Panamli, can be dlistiniguished fr-om the middle par-t of the (Li u format ion, shows a fromt ''( ,cul"' c",io'~ Pilsbry and olsson suigfiu ether niodificat ion in Iie( rounded outline of thle body gested the lprobahilitY of local races of at widely spread wh-Iorl. At thebeginn of thle body whlorl of this species. ('cljiei lu g!plobaUN(8 Pilsbry and Olsson
slpeciliienl the upper ca rina is moderately sti ong, thme (1945-32, p). 66, 1)1. 7, figs. 4, 4a, 1932), also from the basal ca rina is wveak, and the peiphjeral anguat ion is Pleistocenie of western Panama, p)rolbably is a, variety, faint. These carinae a tid angumlal ion rap~idly disappear. or subspecies, of '' .' (;ovs ith a, sculptured base. Tbius specuien is larger- than the, licariiat e and tiricari- The Ecuiadoreanm formn ''Ciculis'' cosm iu Bartsch nate for~ms. Inasnimuch as mature bicariniale anid tri- (1907, p). 17-3, figs. Sa, b, c) also is closely :allied to carnal e formIls are rounded near thle pemistomle, tile. ex- ''C.ircvlus' cro w" but is characterized by a. slight c(1)timnal features of the( r-ouindedl specimen ate p~re- (lowiwvar- bending of the upper margin of the, peristoine suimably correla1ted witi1 its size. Toula 's illustrations, wh-lere it extends forward. Though the peristorte, of however, show a shell of itioder-at e size, thle body whorl the tvype of ''( 'culus'' cosmiujN is damaged], four speciof wlichl is rounded at, an early stage. muens ili thme type (and only) lot have a, perfect lperistomie.
C 'clwlrc ISU\ wuagowis. occeu rs iii the ( ercadlo Thle seven specimens in the, type lot have very weak forn ia tiomi of thle DI oiin ican Republhce a ild ill tlie Bow-, umbilical sculpture. ''(7rculuoi' oc hdcis Pilsbry deli fornitatfionl of Ja ninlica Tuel fem available Slpeci- and Olsson (1941, 1). 48, p1. 9), fig. 3), from the Pliocene imetis front thie 1)011111icali IRepliblic aliI Jaliaiia, aIre of Ectuador, shows (lownwa rd bending of tile peristome t r i ca r~iina tc. It xN as foriely thlough.It thiat tile Gattiitan iiil 510 e1( c)~(omparediN with ''( ircullH' cosml. ? formil coldl be differentia ted by thle wveak sculpture, onl ( yclovstremiscas t;'icari?atu (C. B. Adams) (Pilsbrv thle uinibilical wall (odig,1928, 1) 441). Thlat amid ( lsson, 1945, P). 271,1)1. 28, figs. 3, 3a, 31)). living sculp 'Lure, howe ver., is too va na1 ihe for coli sister t, differ- Oi tilie P~acific, coast, of Panami'i is similar to the trielItI iatioii. cariiiate species so far mentioned. It has, however,
Closelyv rela teil forms a"we living inl thle xesrmfaint axial riblets b)etweeni the periphery andl suture, At Iaiiti(, ami~ldi the(stecii Pacific. "''(vu tiUU~ :1and therefore is iiiteriediate 1)etweel n cflOC/Cs and (Bush) (1897, P). 127, 1p1. 22, fig -s. 6, 10, 1 0a, 12, pl. 2:8, OYClO truaic s~s figs. 10, 15), ranlginig fr-ont ("1ape Maht teras to Cunba, is ( )ccurrence: Lowver, middle, and upper parts of conlsistemi fly t ricar'inate and1 elarges Iore rapidly, so Gatumi formation middlee and late 'Nliocene). JA)XVer


part, localities 138, 138a. Middle part, eastern area, The subgenus Systlonmphal as (Pilsbry and Olsson, localities 146, 147b, 147f, 147g, 147h, 153a, 155c; 1941, p. 48; type (orthotype): Systellotmphalus perornawestern area, locality 161. Upper part, eastern area, tus Pilsbry and Olsson, Pliocene, Ecuador), with which locality 173; western area, locality 185. Cercado and Pilsbry and Olsson associated species closely allied to Gurabo formations (middle Miocene), Dominican "Circulus" liriope, may be defined as embracing species
Republic. Bowden formation (middle Miocene), Ja- that have axial riblets on spire whorls and axial wrinkles
maica. on the base of the body whorl adjoining the umbilicus.
Genus Solariorbis Conrad Hapalorbis is not known to have survived the Miocene
Conrad, American Jour. Conch., v. 1, p. 30, 1865. in Caribbean waters.
Type (logotype, Dall, Waigner Free Inst. Sci. Trans., v. 3, pt. 2,
p. 414, 1892): Delphinula depressa Lea, Eocene, Alabama. Solariorbis (Hapalorbis) hyptius hyptius Woodring, n. sp. and n.
Subgenus Solariorbis s.s. Plate 17, figures 16-18
The subgenus Soliariorbis s. s. is characterized by Small, thick-shelled, depressed, body whorl increasing relatively large size, faint spiral sculpture (micro- rapidly in diameter. Periphery sharply or moderately scopically punctate in the type species), and a wide carinate, except at and near peristomnie. Umbilicus umbilical wall on the body whorl adjoining the aperture. very narrow, asymmetrical. Umbilical wall very narSolariorbis (Solariorbis) strongylus Woodring, n. sp. row, the angulate( umbilical border being inserted almost flush with base of body whorl where it emerges
Plate 17, figures 43-45
t from umbilicus. Parietal callus moderately thick.
Of medium size, thick-shelled, moderately depressed. Height 0.7 mm, diameter 1.4 nmmn (type).
Periphery faintly and bluntly angulated, except at and Type: USNM 561323; paratypes Stanford Univ.
near peristome where it is rounded. Penult and part Type locality: 147b (USGS 6033c, Panama Railroad,
of preceding whorl sculptured with closely spaced spiral about 3,500 feet (1,065 meters) southeast of Gatun threads. Spirals become faint and even disappear on railroad station, Canal Zone), middle part of Gatun body whorl, but most persistent near suture and just formation. above periphery. Under strong light base shows barely The very narrow and asynunetrical umbilicus, and discernible microscopic spiral striation. Umbilicus very narrow umbilical wall are conspicuous and characmoderately narrow, asymmetrical, bounded by a crude teristic features of this species. It is closely related to spiral ridge, which is slightly roughened by growth the type of Hapalorbis: "Circulus" liriope Bartsch wrinkles. Parietal callus thin. (1911, p. 231, pl. 40, figs. 7-9), which is represented by
Height 1.3 mm, diameter 2.4 mm (type). Height the type and an imperfect specimen, both dredged at a
1.5 mm, diameter 3 mm (largest specimen). depth of 21 fathoms off La Paz, Lower California.
Type: USNM 561322; paratypes, Stanford Univ. The fossils are smaller, more depressed, have a smaller
Type locality: 138 (USGS 16909, Transisthmian more asymmetrical umbilicus and narrower umbilical Highway, 1.6 kilometers northeast of Canal Zone wall, and lack a spiral thread above and below the
boundary, Panamd), lower part of Gatun formation, peripheral carina.
The weak sculpture and moderately narrow asym- Solariorbis hyptius proper was found in the lower and
metrical umbilicus are characteristic features of this middle parts of the Gatun formation, but is rare except species. It is represented by 13 specimens, all from at the type locality. The 68 specimens collected at the the type locality. type locality and the 2 additional specimens from the
Occurrence: Lower part of Gatun formation (middle middle part of the Gatun have remarkably uniform Miocene), localities 138, 138a. characters. The five specimens from the lower part,
however, are not so sharply carinate and reach a slightly
Subgenus Hapalorbis Woodring, n. subgen. larger size.
Type: Circulus liriope Bartsch, Recent, Gulf of California. Occurrence: Lower and middle parts of Gatun formaThe name Hapalorbis is proposed for a minor group tion (middle Miocene). Lower part, locality 138a.
of Solariorbis consisting of small carinate species that Middle part, localities 146, 147b, 147f. have a narrow umbilical wall on the body whorl adjoin- Solariorbis (Hapalorbis) hyptius anebus Woodring, n. subsp. ing the aperture. The type species has a spiral thread
above and below the peripheral carina-forming thread. Plate 17, figures 34-36
Others have one to three threads below the periphery Resembling S. hyptius proper, but larger and
and one or two above. Still others have none below or umbilicus correspondingly larger. Peripheral carina above the periphery, flanked above and below by a narrow low spiral thread.


lleiglit, ().9 inin, diameter L.5 inni (type). Type loettlity: 138 (USGS 16909, Trimsistliniian
Type: USNM 561324. Highway, 1.6 kilonieters northeast of Ca.iial Zone
Type locality: 185 (USGIS 83813, Caribbettit coast,, boundary, PaiianiA), lower part, of Gittun formation.
we',,t of Rio MI-ilel, Pail"I'ma), upper p, rt of Gattin Epi.Ncyr ia regalia, -N-lilch is based oil one specillien forl I ).I t 1011. from the lower part, of the Gatun formatioii, is the
Tlil subspecies is based Oil two specimens front the largest, E'p i,, cyiiia so far described. It, I's most closely upper part of flic Ga tilit, formatioii. Thougli the spirals related to two species liviiiP),- in the eastern Pacific: E. flaikitig tlie periplierY are iiarrower Uid lower than ?iichob ont (Strmig atid Hertleill) (1939, p. 241, pl. 22, tllo.,(, of "Circvb/s" liriopo', 111C sculptund pattern is figs. 2-4; Ptmaniii) latid tlie closely\ allied E. bolimxi
S 1111(" "11--estilig close relatioiislilp. As ln(ficajed Pilsbi y and Olsson (1946, p. 11, pl. 1, figs. 6-8; Colombia 1,)A- the iiame, however, aIllance with the smaller and PeHi; Pleistoceiie, western Maiianift). Oil both
-Tipalwb'?*, ftoin tfic nii(Idle pat-t of the Gattill formation Recent, fornis the marina is exposed oil the later whorls is Iliotight, to be clos-ei% Botli Solaviorbi, hyplivs of the spire. E. i icltolsoni evidently is inore depressed
Zn fliaii E. meg(itia, mid E. bolirari has'a slight migulation
propei- ai)d S. ItYPti i, attebas have ft depressed outlim, aud verv itarrow uniNliettl -xN-all, whereas "Orculusy) oil the bodV %V1101-1 above the perlpllel. N.
E, wi. o (Pilsbry aiid Jolinsoll) (Pilsbry, 1922, p.
is less depressed wid has a wider uinbilicial wall.
371), pl. 37, figs. 5, 5a), the otily otlier described fossil A Plioceiie species from Ecuador, "Pwudorotella"
lci s VllsbrY and Olsson (1941, 1). 47, pl. 9, fi( 2; 1945- s es from the Caribbetaii region (Nfioceiie, Dominican Republic awl, Jamaica), has strong regularl.N spaced ,521 1). 51, 1952) lias (It(, S111110 SCUlptura.1 patten ,is t, t,
solell Mrbl*" (ri cbvs alld "Ciliv?1his" b Vi0j)C, but se"ratimis oil the peripheral variiia.
has, a lictivi- callus facet almost closiii- the IIIIII)iliclis Occurrence: Lower part, of (latim formation (middle wid is sculptured with two spiral threa(Is above the Mloceiie), locality 138.
periplicrY, TI i e R ccei I t, Pail all) R, I itiiii ella Family RISSOIDAE
C. B. Adianis (PilsbrY aii(I Olssoji,, 1945-52, 1). 278, pl. Subfamily RISSOINAE
3, :), 3b, 1945; p. 51, 1952) lacks spirals above
7, 1! Z7- Genus?
the penpliery. "Alvania" aff. "A.'' epulata (Pilsbry and Johnson)
Occili-retice: Upper part of Giattin forniatioii (nilddle
es eril Minute rapidly etil.axgiiig. Protomich very large mid bite Nilocene), easterii area, locality 173, t I tare.t, l0e.alltv 185. for size of shell, cotisistizig of 2 / rapidly eiilarging
smooth whorls. Reniaiiiiii,4, 2/1/4whorls sculptured with Genus Episcynia Mbrch closely spaced axial mbs (17 oil body whorl), between
Wweh, Alahd ozool. Bldtter, Baijd 22, p. 15,5, 1875. whicli are closely spaced spiral threads. Base sculpType inornala (d'0rbigiiy) tured witli tbree wider awl more widely spaced spirals.
( olorhlln il orwltalll (1,01-bigily), Eeeellt, West 111dies. Outer lip vaxicose, its interior iiiaccessible.
Iii the westerii, Atlaii[ic Ep *. cqiii(t raiiges from North Ifei,,Iit 1.2 nim, diameter O.'d min.
Carollim to Brazil, alld III t'lle eastel-il Pacific froln Two mimite speciniens, both found I)Nr T. F. Sawa crilz Islam] Calif to Pel- ,. '\Iiocelle species Thompson iii tlie Gatmi formation, are the only ftoin Florida, alid the caribbeall recioll al-e flie earliest rissolds. Tliey evidently are coi-tspecific and are closely allied to "Ri,, soa" cpulat;i Pilsbry and Johnsoii (Pllsbry, Episcynia regalia Woodring, n. sp. 1922, 1). 3,S4, pl. '34, fig. 5), a, Mlocciie species froni an
unklioNN-ji locality in t1w DoniMican Republic. That Pljte 18, figiin s 4, 8 species I,- nan-owlx- unibilicate. 'Ilie speelineii froin the
Lai-ge, t It I it -,,I iefled Nx- I iods 5. Sutut-eslifl I low, loafed lower paxt, of the GaAlin forinatioll is ininiatur, and has Oil pci-ipllel ,11 c,11,111a of prece(lHig whot-1, even at a, narrow umbilical groove, blit, the mature specimen Peristoille. Penpliel-id carilla, 11111111tely aild irregularly from the upper part of the fornia.tioii, of approximately ro(I-Ilene(I I)Y- exaggerated gl owtll -,NTiiiIdcs. Sinillar the sanie dilneiisions as the type of "Rissola" epulata, is .,I-o\Vtll N\ rjllklcs adjoin salute oil later part, of body completely tiontinibilicate. wliod. Umbilical lialf of Nise tii(I unibilical wtfll Rissoids niore or less, similar to the Gatun species tire
sc(IlphIn'd \\'Itll 111ol'o -,I rm IgI y empliasized <"I.o\\-tli geiierall\' referred to flie gemis Almi ia (Risso, 1826, p. AN-1-1111des. Upper half of umbilical wall fliso sculptill-ed 140; logotype, Nevill, 1884 [18851, 1). 105, Alvania witll two 11arl'oN\' Spiral 1:11reads that, disappear neax curopea Risso= TUIrbo ciniex Unite, Recent, Mediterpensimile. Umbilical bonier slialply .1,11"Illar. 11111011111). The type of Alvania is four tiniest as large,
Height 2.7 111111, (Iianietei- .5.3 min (tYpe). mid lias a, relatively niiieli. smaller protoconch, coarser
T.ype: USNM 561325. sculpture, atid libations oil tl)e interior of the outer lip.


One or more of the numerous generic and sul)generic The type (and only) specimen of this species was
names proposed for European, Australian, and Neoze- collected from the upper part of the Gatun format ion
lanic rissoids may possibly be suitable for "Alvania" at Mount Hope. It is closely allied to It. tpp/
aff. "A." epulala. Cossmann (Woodring, 192, p). 366, pl. 2S, fig. 10),
Nevill's designation for the type of Alcan iia-"type which occurs in the Bowden formation of JamaiCa and A. cimex Lin. [as Alv. europaea Risso] "-appears to be in the Cereado and Gurabo formations of thle 1)ominiCan the earliest valid designation. It has the same effect Republic, but has a more widely expanding prtocolich, as numerous designations of Turbo citnex Linn6 and the slightly narrower spirals on the early whorls, more much later designation of Alvania frminrillca Risso, inflated fasciolelike swelling, and( wider space between
also a synonym of Turbo cimniex (Gordon, 1939, p. 29). the swelling and the lowest spiral. The Recelt Wet
Occurrence: Lower and upper parts of Gatun forma- Indian and Florida species identified by Dall (1 S90 -19003,
tion (middle Miocene). Lower part, locality 136a (1 pt. 2, p. 343, 192) us tL 'cndcllala Philippi has a
immature). Upper part, eastern area locality 173 (1 smaller protoconchl, coarser sculpture, and less inflated
mature, protoconch crushed during examination). fasciolelike swelling.
Family RISSOINIDAE Occurrence: Upper part of Gatun formation middlee
Genus Rissoina d'Orbigny Miocene), eastern area, locality 177c.
Genus Rissoina d'Orbigny

d'Orbigny, Voyage dans l'Ambrique Mridionale, t. 5 (Mol- Family XENOPHORIDAE
lusques), p. 395, 1840. Genus Xenophora Fischer von Waldheim
Type (monotype): Rissoina inca d'Orbigny, Recent, Perd and
Chile. Fischer [von Waldheim], M[usuim-l)Demidof, t. 3, p. 213, 1807.
Subgenus Zebinella Mdrch Type (logotype, Harris, Catalogue of Tertiary Mollusca in Ithe
British Museum: p)t. 1, Australasian, p. 233, 1897): Xenoph~orn Mirch, Malakozool. Bliitter, Band 23, p. 47, 1876. British Mseu pt. 1, aldstIheim]. 253, 1897) .nophora
laeviyata Fischer [\on Wa1hlteini] ("Troclios cotwbh1/lioplhora.. Type (logotype, von Martens, Zool. Record, 1876, p. 30, 1877): Ginel., Bose, Born"'= Trochus couchyliophorus Born, Iecent
Rissoina dccussala (Montagu) (Helix decussata Montagu), West Indies.
Recent, West Indies and Florida (described as a British
species). Unidentified species of Xnophora are represented by
Rissoina (Zebinella?) species two molds from the Gatuncillo formation and an incomA poorly preserved altered shell from the Culebra plete mold from the Culebra formation. formation is assigned to Rissoina on the basis of outline and sculpture. The outer lip and aperture are not Xenophora delecta (Guppy)
preserved. The sculpture, consisting of narrow axial Plate 22, figures 1, 2,4
ribs and fine spiral threads between the ribs, suggests Phorus agglutinans (Lainarek), Gatbh, Am. Philos. Soc. Trans., the subgenus Zebinella. n. ser., v. 15, p. 241, 1873 (Miocene, Dominican Republic).
Occurrence: Culebra formation (early Miocene), Phorus delecta Guppy, Geol. Soc. London Quart. Jour., v. 32, p. Gaillard Cut, locality 991). 529, pl. 28, fig. 10, 1876 (Miocene, Dominican Republic).
Xenophora delecta (Guppy), Maury, Bull. Am. Paleontology, v. Subgenus Phosinella March 5, no. 29, p. 134. pl. 23, figs. 8, 9, 1917 (Miocene, Dominicani
R/epub~lic). Pilsbry. 1922, A\cad. Nat. Sci. Phila. Pmoe., v. 73, M6rch, Malakozool. Bldtter, Band 23, p. 51, 1876. Republic. Pils 1922, d. Nat. Si. Phila. Proc. 73,
p. 385, pl. 32, figs. 7, 8, 1922 ("dilecta" by error: Miocene. Type (logotype, Nevill, Hand list of Mollusca in the Indian oinicn Repb drig rneieIst. Wahingto
Dominican Republic). 1W00dring, (Carnegie Inst. 11ashington 'Museum, pt. 2, p. 73, 83, 1885): Rissoina pu~chra (C. B. I
Museum, pt. 2, p. 73, 83, 1885): Risoina puchra (C. B. Pub. 385, p. 376, pl. 30, figs. 3, 4, 1928 (Miocene, Jamaica).
Adams) (Rissoa pulchra C. B. Adams), Recent, West Indies. P 1 l.3 Bri. M4 1 amoo.
Xenophora conchyliophora (Born), Maury, Bull. Am. PaleontolRissoina (Phosinella) oncera Woodring. n. sp. ogy, v. 5, no. 29. p). 133, pl. 23. fig. 7, 1917 (Miocene, Dominican
Plate 23, Figure 3 Xenophora aff. lroch (iformis (Born), RIutsch, Schweizer. Palaeont.
slender. Protoconch of 3 smooth rapidly Gesell. Abh., Band 54. no. 3, p. 48, pl. 2, figs. 2, 3, 1931 Small, slender. Protoonh of 3 smooth rapidly (Miocene, Venezuela).
enlarging whorls, the last half whorl obscurely angulated. Sculpture reticulate; axial ribs slightly wider Moderately large, widely umbilicate. Spire low,
than spiral threads. Four spirals at beginning of periphery somewhat extended. Sculpture above pepenult, five on later half. Outer lip strongly varicose. riphery, between agglutinated shells and shell fragFasciolelike swelling on base strongly inflated. ments, consisting of strongly protractive irregularly
Height 4.3 mm, diameter 1.7 mm (type). rippled threads. Base sculptured with more uniform
Type: USNM 561332. rippled arcutate threads parallel to columeller lip, which
Type locality: 177c (USGS 5855, west side of Panama is broken back.
Railroad, opposite Mount Hope cemetery, Canal Zone), Height 25 11m, diameter (incomplete) 46 nun (figured
upper part of Gatun formation, specimen).


Type: British Mus. (Nat. Listt., Geol. Dept., Geol. Pliocene age in Italy. X. d lecta has somewhat coarser Soc. LIondon 12842. sculpture than those species.
Type locality: Dominican Republic, MNliocene. The Recent Caribbean X. conchyliophora has a long
An incomplete Xenophora, found by T. F. Thompson history in the southeastern states and is one of the few in the upper part of the Gatutn formation at Stanford Recent species recognized in the Eocene of that region. University locality 2(54 near Fort Davis, is referred to The Recent Panamnic X. robusta Verrill, characterized X. decta. The attached shells and shell fragments by the deep orange-brown parietal callus and adjoining with one exception (a fragment of the body whorl of a inner half of the interior of the body whorl, is better Pihos-like gast ropod, attached by the exterior surface) treated as a subspecies of conchyliophora. consist of peleclypods, Aquipecten being most abundant. Occurrence: Upper part of Gatun formation (middle These pelecypods and pelecypod fragments are concave Miocene), eastern area, locality 173. Cercado and side upward, also with one exception: a fragment of a Gurabo formations (middle Miocene), Dominican Remature A yquipectc scisu/ratus. public. Bowden formation (middle Mliocene), Jamaica.
The generally open umbilicus and relatively strong Punta Gavihin formation (late Miocene), Falc6n, sculpture differentiate Y d(htcta from the only Recent Venezuela. species in the Caribbean region, X. conchyliophora Family HIPPONICIDAE
(Born). The Catun' fossil is widely umbilicate. On Genus Hipponix Defrance
specinmens of comparable size from the Dominican Defraince, Jour. Phys. ('him. list. Nat. Arts, t. 88, p. 217, 1819. Republic the umbilicus is narrower and even reduced Type (logotype, Gray, Zool. Soc. London Proc., p. 157, 1847): to a naIrrow groove. ]Rut sch's illustration of a specimen Patella cornucopia (Patella cornucopia Lamarck), Eocene, Paris from the late N Miocene Punta Gavilhin formation of Basi".
Hipponix species
Venezuela also shows only a narrow groove.
The type of X. dlecta is a small specimen, like speci- The Gatuncillo fossils from the Rio Caso va area menes front the Gurabo formation in the collections of include a small presumably immature Hipponix, shaped the U. S. National Museum maximumm diameter 24 like a wide cornucopia. Some growth lamellae are nun). Two imperfect shells from the Cercado forma- exaggerated and there is a faint suggestion of fine tion are even smaller. The Bowden formation of radial sculpture. The muscle scar is not discernible.
Jamaica also has yielded only small specimens (maxi- Length (not quite complete) 9 mm, width 7.5 mm, mum diameter 19 mn). The ripples on the base of approximate height 6.5 mm.
these small specimens, from both the Dominican Re- So far as this small specimen goes, it suggests a
public and Janmica, are so strong that they form nodes. miniature replica of the type species of the genus. Pilsbry figured two large specimens (diameter 51 and Occurrence: Gatuncillo formation (middle Eocene), 50 nim) that are in Gabb's collection of fossils from the Rio Casaya area, locality 38. Dominican Republic, and Maury illustrated, under the
name X. conchylioph ora, a large specimen from the
Gurabo formation. ZHipponix? species
X. tcxtifia D)all (Gardner, 1926-47, p. 561, pl. 58, A poorly preserved limpet-shaped fossil from the figs. 31, 32, 1947), of the Chipola formation of Florida, Culebra formation is doubtfully referred to HIipponix. evidently is an early form of X. delccta. It is umnbili- It is moderately large and elongate, and the apex is cate, but its sculpture is not as strong as that of X. near the posterior end. The apex is worn and pracdilecta. The larger of the two syntypes figured by tically smooth. Preserved parts of the outer shell are Gardner is herewith designated the lectotype. The sculptured with crude radial ribs overriden by crude
widely unbilicate strongly sculptured fragment from concentric thre'(s. The interior is inaccessible. the Shoal River formatim, doubtfully record hd as X. Approximate dimensions: length 21 nm, width 17 t'xtilua, is indistinguislhaible from X. dcheta. It might, mr, height 9 mm. however, be the high-spired subspecies of X. d(h(cta, X. If this fossil is an Hipponix, it is more similar to the d(h'cetafloridana MNIanstield (1930, p. 121, pl. 18, figs. 5, Pacific H. pilo.,us (Deshayes) (an earlier name for H. 6), which occurs in upper Miocene deposits in western barbalux Sowerby) than to Caribbean Recent species. Florida. H. pilosus ranges from California to Ecuador and the
X. dch(l(cta left no descenldents in the Caribbean or Galapagos, anld is found in the western Pacific. It is Pananiic regions. It is closely related, however, to X. recorded from the Miocene of the Dominican Republic ,setneq lh s Fischer, a Recent, west African species, and (Pilsbry, 1922, p. 384). its close Recent, Nflediterranean ally, X. crispa "K6nig" Occurrence: Culebra formation (early Miocene), GailBroi which occurs in rocks of late Miocene and lard Cut, locality 108c.


Family CREPIDULIDAE Crepidula plana Say
Genus Crepidula Lamarck Plate 19, figures 1-3
Lamarek, Soc. Hist. Nat. Paris AlMm., p. 78, 1799. ('repidlda plana Say, Acad. Nat. Sci. Phila. Jour., 1st .tr., v. 2,
Type (monotype): Patella fornicata Linn6, Recent, eastern p. 226, 1822 (Recent, iMaryland to Florida). ID)all, Wagner
United States. Free Inst. Sci. Trans., v. 3, pt. 2, p. 35S, 1892 (.ioc(line to
SRecent, eastern United States). Brown and Pilshry, Aad. Molds from the Culebra formation are identified as n nited States). Brow a Pir, Acad.
Nat. Si. Phila. Proc., v. 63. p). 360, 1911 (Miocene, ('anal
Crepidula sp. Zone). Brown a1d Pilsbry, idem,. v. 65, p). 45. 1913 (Plhistoc 'ne, ('anal Zone). Pilstry, ide ,n. v. 73. p. 385, 1922
Crepidula cf. C. maculosa Conrad (Miocene, Dorinician Republic). Olsson, Bull. Am. PalePlate 19, figures 4, 5 ontology, v. 9, no. 39., p). 159, 19122 (lMiton'mi, northwstern
Pnanni). Gardner, U. S. G'ol. Survey Prof. Paper 112,
Crepidula gatunensis Toula, K. k. Geol. Reichsanstalt Jahrh., p. 535, 1947 (Mioceie, Florid:: se this piublication for other Band 61, p. 498, pl. 31. figs. 12a, b, 1911 (Miocene, Canal citations. Zone). Crypta fortic'ata (Linnd), Gabb, Am. Philos. Soc. Trans., v. 15,
Of medium size, moderately narrow, moderately p. 212, 1873 (Mioctne, )DominicanI Rep)ublic).
vaulted. Protoconch of small specimens consisting of Of medium size, narrow, compressed, flat or conctave.
about 1 whorls of neritoid outline. Deck of small Protoconch of inmmnature shells consisting of 11/4' to 1 specimens moderately deep seated, bearing a wide rapidly enlarging whorls of neritoid outline, destroyed
shallow median indentation, at later stage by encroachment of aperture. Deck
Length 28.5 mm, width 17.5 mm, approximate height bearing a moderately deep narrow ab)apical marginal
10.5 mm (figured specimen). indentation and a moderately deep very wide median
A species of Oepidula from the Gatun formation is indentation.
comparable to the Recent C. 'rnaculosa, to which atten- Length 15 mm, width 10.5 nmn, height 2 mm (larger tion has recently been called (Stingley, 1952). As figured specimen).
pointed out by Stingley, C. rnaculosa has a pedal muscle Slipper limpets recovered from the apertures of scar adjoining the adapical insertion of the deck and the Gatun coiled gastropods agree closely with the Recent edge of the deck has a very slight median indentation, Crepidudla. plana. All the fossils were found in the lower whereas the better known and more northern C. part of the formation. C. plan is already recorded
fornicata (with which C. minaculosa has been confused) from the Gatun formation of the Canal Zone and from lacks the muscle scar and has a pronounced median late Miocene strata in northwestern PanamAi.
indentation. A species of Crpidulda that has a similar outline and
The only fairly large shell from Gatun (pl. 19, figs. similar deck characters is living in the eastern Pacific 4, 5) is attached to a crab carapace and the interior is Panamic region. It, presumably is C. nivea C. B. inaccessible. Owing presumably to inequalities on the Adams, but is generally known as ('. tunmanaria Gould. carapace, this shell has two faint depressions and cor- The few specimens of this species from Panamai in the respondingly modified growth lines. The other shells collection of the U. S. National Museumni have slightly (all of which are small, ranging in length from 1.5 to 12 deeper deck indentations than C. plane. millimeters) evidently represent the same species as Occurrence: Lower part of Gatun formation (middle
the fairly large specimen. Two that are moderately Miocene), localities 137a, 138. 138a. Middle part of
small show the muscle scar of C. macilosa. Gatun formation (middle Miocene), eastern area
According to Toula's description and illustration, C. (Brown and Pilshry). Late Miocene, Water Cay, gatunensis was based on a small shell (length 2.8 Panami. Miocene, Dominican Republic. Early to
millimeters) like those in the collections at hand. late Miocene, Maryland to Florida. Pliocene, North
That name is available, should the name C. mnaculosa be Carolina to Florida. Pleistocene, Massachusetts to found to be inappropriate for the fossils. Florida, Canal Zone. Recent, Prince Edward Island,
Though C. fornicate is recorded from the Miocene of Canada, to Texas and the West Indies. Trinidad (Maury, 1925, p. 244), it is unlikely that that
species lived in the Caribbean Sea at any time. Family Calyptraeidae
Occurrence: Lower, middle, and utipper parts of The genus Cheilea is not represented in the collections
Gatun formation (middle Miocene). Lower part, at hand. Cheilea princetonia Brown and Pilsbry (1911,
localities 137, 138. Middle part, eastern area, local- p. 360, fig. 2), based on an internal and external Iniold ities 147b, 155c, 157. Upper part, eastern area, locality from the Gatun formation, may be conspecific with 178. the Cheilea from the Bowden formation of Jamaica


idt'tit ified fls tilie Recent, (Caibbean formi designated Maximumn diameter 16 mmi, height 6 mmn (largest
C. c 4u,Iis (I inil!') (Woodinfg, 1 92S, p. 375, p1. 30, specimen).
f igs. 1, 2). Type: Apparently lost.
Genus Calyptraea Lamarck Type locality: Natural Well, N. Car., Duplin
Jzoiainarvr, Soc. 11ist. NzAt. P~aris \Mmhi., 1). 78. 1799.p format ion (late Miocene). '1'xpe (rni'oiiotvpe) I'ei10Ue cruilist s U11116, Recent we'sternl Specimens from the Culebra formation, identified as
I'>ir-ope (alyptraea cf. 0.* C('nfraiU are comparable in size andl
All 1n i ideuit Ified sm111 all ( rlq1;ua Ifin t, has al ec'en tic outline to (7. u,,lrali-s, but iione shows the in terior. All apetx 15, relpresemeltc bY1 ) poor'ly pres'ervedl speduinens" are molds, With tile except ion of onle, whieh was collected
Iroin ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ll ti'Ian unle ft i oio? ou t at, locality 108Oc and has much of the shell preserved.
faos h 111mo.1e lelwofdc olo' orlit The, description is Ibasedl onl specimens from the lower
Vallo" 'Illos.part of thle Gatun formation. The only large specimen,
Calyptraea cf. C. aperta (Solander) from localitN 138 is imnperfec't. The interior of the only
MNIohis of a relatively large reaIvl hIg-spie I pcie fro the ,.'rm N -ii(dhle part of the Gatun formation
('qpir(' a, from tOle (jatiuiedlo Ioniat ion of Madden is inacessile. It, is listed as ( olypirar'a cf. C7. centralis. 1 )asil iiIle(,'aniparable to C)(. aln i/a, which Is-,~ ei The (latim fossils that show the interior agree closely (list rih1)tlte(l I in l( the oceiie and ()lioocelie of wes'ternl within topotY pes of C'. ('ntralis collect ed at Natural Well, Europe atid south elaster iit ite(l Sitates. (Foi citatio N.( Clz. ks poinied out, by DalI and Gardner, Recent 111id sv11llolY~ see Palm-er., 1 937, 1). 145.) 1ii tropical specimenl s are smaller thian those from the 'Miocene. AkilericaI C. ajn i, or- a comlp,11rale forml, is i'((o)ml(e Recent specimens in the collect ion of the U. S. Nat ional
fro t iePaloce i ofIriiia ( U idt le Ece ieof Museum, representing localities from (Cape Hatteras to (. 'oliia ail Perd. thle West In1(lies, are not more than a third the size of
Occur reduce : (at tumcillo formaftionl (hit e Eocefle), large, INliocene fossils. Two large Recenit, shells, howlocalities 91, 12. ever, are exceptions. One, which has a maximum
diameter of 11.3 niillimeters, wavs cataloged at an early
Galyptraea centralis (Conrad) (late and is labelled ''West Inies." Thle other (inaxiI efeedibeie c(ii r tmrli, ('anu, Aini. Jour. Sei,, 1st ser., N'. -1,1 mum11 diameter 15.5 mnillimieters) was in the Henderson
1). :3 18, 1841f (M iocoiw, Nort Ii( aroliiia, 1). 343)). Conlrad, collection and is lbelledl ''M arco, Florida.'' The reI -ils of tile eiain Tertiary of the tited, States, No. 3 flected edge of the platform of both is closely appressed,
Fo"uils of tie M\i remii fornIlat ionl of the Unlited( st :ites' ) 81), lk hto h ete u~pai( / a itletp
1] 45, fig. 5, 1845 (Miocene, North ( Jhilliw.i)o lita tle Tetry uoenC liinitetp
Tror il(e sp. indri ., ( alA), Am. Pliflos. Soc. Trais., v'. 13, 1). 242, ~ gns rbll r pcmn fta
1S7 '(Ti ioceiie, 1)olliieaui Rtepublic). Species with erroneous locality data. Should it name be 7 Tor/i' ci ollillsjj(i tt Aezid. Nat. Sri. Phila Jouir., 2d ser., (hesira be for the sinall Recent race, i ay be, designated
v. 8, 1). 34 2, Ill. II1, figs. 1I, 11 a, 1881 (Mliocenie, C'osta Rica). ( Caly ptraa c( n ,ali.s- caideana (d'Orbigniv), as indicated ( 'lypim' a ccitirei; (( 'mi:id). 1)alI, Wagner Free Julst. S'* by Dall's svnonyivlv. Pliocene fossils from thie Caloosa'Vi ii., ., p 2,p. 53,159 (Macrie o Iecet). hitchie marl of Florida have a maximum (liatlieter of
i\lairY, Acad. -Nat. Sri. Ph1ila. .Jour., 2d ser., v. 15. p). 100l,
Ill. 131, fig. 6,, 1912 (Miocrne, Triniidadi). MauvNwYork 10 millimeters and therefore are intermediate in size.
Avad. sri., scieat itic 'Sn rve *V of Porto RIica ali(l iri ISlan1ds, The Recent Pammamic (7. uant il/ais Broderip is larger
v3, 14t. 1, p). 18, 19 20t (Miocetie, 1'lierto aRico). Pilsbry-, t han C7. o' ideab/is, and has a thicker shell and mottled
Ara iiJ. Nat. Sci. Piilai. Proc., v. 7:3, 1). 385, 1922 (1OlIl, brown color p~at tern.
I ou iiirliI riitli) I 1Bl.Ai acn 1g, I Occurrence: C ulebra format ion (early INIliocene ; Canlo. 12, 1). 2 131, I)1. 13, tig. 2. 1925 (MIiorcene and Plioeoiie
Trililimi) ruir ..S.(rl re r. PiI'12, lypti(ca cf. (. centraIl' ), Gadllard Cut, localities 99b,
p562, pl. 56, tigs. 3-5, 19 17 (M\iocre, Floridai) see this 99C, 100), 1lO8c, I1 Ia. Lower tand mniddhle lparts of Gatun
puiliirationl for otlwri cita(tionls, formation (middle, 'Miocenme) ; lower part,, localities 137,
?( e11Yp/l-r cf. n iu/rel. (( orirail ), H ubb~ard, N. Y Acid. Sri., 138, 138a ; middle part eastern area, locality 147j,
Scientfifi lir en*ev of Porto Rtico and Virginl Islanlds, N% 3, pt. 2, ('/ uroRc
p). 133, 1920) i iocce, IPucit o IRico). N\I amrv, 1925, linisi i .P'l I(f .ciiils acvIIbe
Serv. ( iol. 'M ill. Moll. 4, p). 65, Ill. 1, 5is 10, 1925 (Miiciii ?( 'ost a Rica, ?Hrazil. Late INliocetue(?), rinidlad.
Btzilj. M~iocenie, D~omninican Republic. Early to late Miocene,
O f lute hition size, cliveuhart in vent tral p~lant, apex central. IN Iarxland to Florida. Iliocemie, Trinidad, Florida.
Pro octuh o abtiI I~2 t ouilvitilat(N, rpidy nlag- Recenft (small race) ('ape Hatteras to W~est Inidies. ill-, \X liorls. lPie edgIe of })hltforlin 'onivex forward; Genus Trochita Schumacher
jefIcct C I 'I l t ii ela Ie~le 101 P )elyaJ~l'e5e frmn ng Sr'lilluaclier, Essa i (I'luil loliveaut syst &oie des habitat iois (liC a relat ik'ehv high1 i unibilimishike openiing. vers tesic's6, 1). 57. 18-1, 1817.


Type (logotype, Rehider, Biol. Soc. Washington Pi'oc., v. 56, Trochailclla trochi ifis (Gmiicit), lacujiji c, Jour. ( oncli viip. 41, 1943) : Troch ito spiralis Schumacher (= Truch its radi- ologie, t. 90, p). 240, iii unil wred pl., fig. 2. 19501 (H11 l
atis Lamarck= Tuirbo Irochiformis Borni), Recent, Ecuiador to Pleistocene, Morocco).
Chile. Of nmediuim size, itodera te 'lv lowx spiredl or- 110(1eI cl *v
Trochita has at thick shell, distinct suturev, and high sp~ired, apex brokei. Sciilptmvre (015151 Pi of moderately strong to strong radial sculpture. The free hleavy crude axial rib~s. 'Plnt oii broken back to edge of the platform is convex forward, except at the inisertion. distal margin, where it, bears a narrow idlentatimn. The \laxinimn diamneter- 28.8 mill1, lcigh it, (illcoiilet () coltimellar edge of the platform is reflected only at, its 10.7 mmn smallerr figuredl specimen). Maniiiii d jam11insertion. On adult shells this short reflected border is eter 43.5 inni, height (ahuiost, (olnpete) 27 mim (larger molded on the platform, like callus. The genus and its figured specimens). species were discussed l)y JRehder (1943) in the pulblica- This calvptraeid is rej)Iesetted liy two specimlenls tion cited for the type (lesignmat ion. from the lower part of the (haiin foiniat io, 1both
Trochita heretofore has not been recorded front the collectedl ly T. F. Tlhomupson. TlioiighI tile interior of Caribbean region. It is now extinct there, tand in thle the larger specimen is inaccessible :lid, tile platformfl of western Atlantic is limited to the Falkland Islandls and] the sinaller is broken far lba('h, tbey are identified wvith the coast of Argentina. Thioug h it occuirs ithe icIoee Coi)sid~lei'a~e (olifidlece as iroch d/a lroch, ijurin is. The and Pliocene of ( alifornila, in the eastern Pacific. it, is Ilni(Idle part of thle ( jatnill format ion inl tile wvestern area now found only south of the equator. The survival of at locality 151 yielded a wvorni tbiik-shielled apical frogthe genus in west, African waters-a genus otherwise iIeitl listedl as Truch~ sP 1. l(illlt and J)00r
confined to thle Perutvitan, Mugellanic, andl South preserved fossils fr-om the middl In ember of the African provinces- is more ireadily understood in view Cainiito fornationiii the ("atnll Lake area anid the of its occurrence in thie 'Miocenie of thie Caxibbean region 0ulebrai formaftion suggest, that, t li lineage of T. tiuch iand in the Pliocene and Pleistocene of west Africa. /ii scaii le tra4ced l)a"ICk to the( 1late OJligo ce I Ie. Nonet
The West African species is considered conlspecific withl of these Caimiito and ('ulebr-a fossils, however, is uiithe 'Miocene Caribbean fossil and the1 IReceiit eastern equtivocally idlentifiedl. Pacific species. It is an expectable fossil ill the West Troch ia trochjformi, nsiow rati-es from Manta, LEnaAfrican 'Miocene. dor, to Valparaiso, Ch]ile. It. is low spired to high
Trocitatrohifrmi (Brn)sp~ired. (-)nt low-spired shells the pla tform is almost
Trocita rociforis Brn)flush with the base of thle sin11I; onl highb-spired shells it Plate 19, figures 11-14 is a, considerable distance above the base. The heavy
cruide axial rib~s are characteristics. The larg-est Recent
Turbo Irochiformis Born, Index iisei Caosarei Vindohlieiei11i m h olcino ie .S ainlilsu
p). 355, 1778 (sole citation: Knorr, pt. 3, p1. 29, figs. 1, 2, 1768' hsecae iii tm oliaeteri of t65 U.iS.iNtioalMs. ~ t "'Antillean Islandls").haa 1,1I-1,11 ianlro65mlmers
Trochuis radians Lamnarck, Lncvyclop6die inethodiqite, Ilistoire A small formi of Troc,*Ila trc /r s(recorded aIs T.
naturelle des vers, t. 3, pl. 445, figs. 3a, b: Liste, 1). 10, 1816. radiaos) occurs in formations of .lPlioceiie age ill CaliLamarck, Ilistoire naturelle des aninmux sans vertMbres, t. 7,fri sfrnrha ie at ~radsrc Anl
p. 11, 1822 (Recent, 'mner des Antilles"'). onaa a ot steStadsrc Anl
Calyptraca (Trochatre) trochiformis ((nmelin), c'Orbigny, Voy- and Anderson, 1907, p. 60, pl. 2 1, fig. 1; Woodrmng and
age dans l'Amn~ique XM6ridionale, t. 5, pt, 3, 1). 461, pi. 59, Brainlette, 1950 [1951], 1). 72, p1. 13, fig. 19), in Santa
fig. 3, 1841 (Recent, Chile, Perd; Calqptraca radians in explaiia- Barbr ony al a n mide\ocefrs
tion of plate). Nickls, M\anuels Ouest-Africains, t. 2, 1). 73, front California have been identified as True/i ta cost(lhIta fig. 99, 1950 (Recent, Angola). Lecointre, Morocco Ser-VICe Conrad (Eldridge and Arnioldl, 1907, 1). 14S, pl. 32, fig. (16ologique, Notes et -\16m. 99, t. 2, 1). 108, 1)1. 25, figs. 1- I, LoladCr,192p.2,p.6, g1),ndat
1952 (Pleistocene, 'MTorocco). 3 oladCry13,p 6,p.6,f-.1) dIt
Iiifundibtlum, trochiforme (Gunelin), d'Orlbigny, Voyalge (lais Miocene forms have been named ''( alyptraa" d' 4wl'Airique M~ridionale, t. :3, pt. 4 (Pal~ontologie), p). 158, blociN+ Clark (1915, p. 485, 1)1. 70, fig. 9) and lp 1842it (Pleiscene, c k)e).,C nh lga cncv 1 traea'' maritini Clark (1915, p). 486, pl. 70, fig. 8). As
Trohit raias (amaek) Reve Cochooga Ionia, i sggested by Grant, amid Gale, these heavily ribbed
Trochita, pl. 1, species 3, 1859 (Recent, Chile). Sowverhy, t, I. ~ oLt
Thesaurus Conchvlioru m, v. 5, p). 64, p1. 451, figs. 95, 96, 99 icn 1 ~ flS 11~n in age 101olate 1883 (Recent, Chile). Relider, Biol. Soc. Washington Proc. MYiocene, are probably to be refer-redl to I rue/uta ohi v. 56, p. 42, 1943 (Recent, Ecuador to Chile); see this jpublica- for'mis. The inadequate tJvpe material of Troech Ha tion for other citations and synonymy. costellat Conrad (1857b, p). 195, pl. 7, fig. 3') consists of Caly~ptraea (Trochita) trocimiformis (Ginelin), Grant, and Gale,
San Diego Soc. Natural History Mr.,.1,p75p. 3 two miolds showing traces of relatively fine ribs. Addifig. 11, 1931 ('Miocene and Pliocene, California; Recent- tional specimens fromt the type locality (Gaviota Pass PanamA to Per6). in the western Santa Yiiez Moulita ins, Santa Barbara


Countyl, Calif.) have not b)een described andl the age is Of mledilu size, elliptical ini venitral plan. still lnniion Protoconch of about 1k42 rapidly enlarging whorls.
I amn indIebtedl to It. T. Abbott for pointing out that Shell smooth to diameter of 1l/ to 3 mmti. At that Born's Tvubo true/u forntis is ain earlier namne for stage the shell is elliptical and] the apex lies far to the Lam arck 's 7 roe/i us ra(/ea n rear. Sculpture consisting of closely spaced crudely
Occurrence: Middle miemlber of Catimito formation roughened radial ribs, some of which bifurcate and a
(late Oligoceiie), ( htun Lake area, localities 57 few of whichi unite as they extend outward. Right (Truch I1? sp.), 57a (Troehila cf. T. troehijuris,). anterior border of cup sharply anguilated, joined to Culebra formation (early Milocene), Gaillard C'ut, side of shell aIt level far above ventral margin of cuip. localities 115a (Troch ia? c'f. T. lrochFfurrns), 11 5b Maximuni diameter 27 mmi, height 16.3 mmn (figured (Ttroe/e ita cf. T'. iruch ;formnis I11CY (Trocleit cf. T. Irochi- slpedllfen).
fumis.Lower part of (4atun formation middlee Type (lectotype, the specimen figured by Gardner): MNiocene), locality 1363, 1 36a. Middle part of Gatun USNM 112783. format ion (nnlddle Miocene), western area., locality Type locality: USGS 2212, Tenmnile Creek, Fla.,
161ic (Truck a? slp.) MIiocen e, California (id en tifica- Chipola formation (early NI iocenie). tionl dioub tfuil). P'liocen e, Ca]liforn ia, MNIorocco. Pleis- Specimnic s fromt tI e middle part, of thle Gatun formaitocenle, Chile, Cape Verde Islands, Morocco. Recent, tion at, the Gatun Third Locks excavation closely Manta, Ecuador, to Valparaiso, Chile; Cape Verde resemle Cruacib u/unt chpolan urn? in characters of proIslands, Angola. toconch, sculputre, anl cup The right side of the
Genus Crucibulum Schumacher cupI of the figured specimen was uncovered, but the
Sdiinnlmr Esai 'u iuvea syt~ie es abiatins esshell is too fragile to uncover the entire cup. Locality
ver Ptosa(, 1). 56, 182, 1817, 155c yile onicmlt specimien. I hw
Type (looype, Burnt, CMehologiral Club Sout herni Clif. the same kind of cup and traces of radhal rib, but is
1Proc., Ito. 56, p). 19, 1946): (iiibulni plan i in SchuniavkTe only tent atively identified as C. cliipolanaurn0.
(WO Pola u rnea Gitin), iHet'ct, Florida and West Intiks. C. eh ipo/ali un was described as at variety of the J. I,,. Gray's (1847, p. 137) designation of Patel/a IRecent Caribbean C. auricala (Ginelin). Undoubtedly auice/(ta as the type of (Wruciuur is not valid In the it is closely related to that species and to the Recent strict sense, as Pate/la aunrculata was not mientioned by Panantic (. spiosurn (Sowverby). The cups5 of all Schiuniiicli em. Schiumacher, however, based] ( 'rucibulurn three are siniilar. The sculpture of C. a uric u/a is p/all ur onl Cheinuitz's Pate//a auxtiiuata wvithou t weaker and more varied t han that of C. c/hipolan urn. mienitionig it by name. Both (_'rucibvu/urn p/awurn and As p~oinited out by Gardner, the protoconch whorls of Patl/a aiuricu/a (a, give'n bilnmial stan'lding by 1)illwynl C. (1 uricula tare wider anid emerge more obt usely. in the year when Schumacher published the generic Both C. a ricuila and C spikosurni are recorded fromt the name ('ucibu/urn, are syiionins of Pate// a ulicu/a M iocene of thle lDoinilican Republic (Pilsbrv, 1922,

'ie recent type designiat ion by Burch, onl the advice A species of ('rucib/ urn from the Shoal River of Keenl, appears to be the first valid dlesigna tion. The formation of Florida anid its Oak Grove, sand, member C. question of possib le virtual miono tvpy, raised by Keen, ch ipu/anurni dudoi cu in (ardn em' (1926-47, p). 367, 1)1. need not V le coiisid crec I. Whatever the staItuls of 56, figs. 1 S -20 1947), has coarser sculpturne thian C. ('ruhuun ruqov-ysahun, thie on ly ot her spe(,cs c/c ipo/an a I. It presumably is not cl4sely relatedd, h ownMeitioi ied I y Sd iunicl e:r, maiy be), ( 'rucii /un was ever', to C. ci Jolii il, as its cuii1s at t ahed to thle side not miioiiolv})ic. of th ie shllt at th WTI lve of W le vent ral margin of the cup).
U n id ci ited Wd1 s fromn thle Coile]s hir fo im qn the DalI designate ed no type mat erial for- C. eli ipu/ale un. Alliajuiela, sandstone nicinber of the Caimlito formlalion, lIn his description lie men01tioned only one locality: the ad INth (' Tagres sand1ston (iicae listedl as ( Wcibu/u in Chlipolai River, a, mile 1 wlow Ba ileys Ferry. lie also exatilin 'Ini ad id eniti ed, however, Sp~ecimnsl from thle
Subgenus Crucibulum s. s. nearby Teninile ('rek locaity, a mile west of waess
Cruicibulum (Crucibulum) chipolanum Dali Ferry. The specimen Iroim thle Teniiiile Creek locality~
I i:ti t 19, tigns 6, 7 figured b Glia (rd ntie is 1 eerewit hI design ed thle Wledope.
WNW=aur-ul vn. cipmn~m IMM'an(T14- lit. 0ccairrenice: 'MIiddle part, of G"a hll format ion middlee
S6., Trtits, v. 31, 1h. 2, p. 34 9, 1892 (Miiqn Floridn). icn) atr U0 oaiis15,15
( 'ratibdd a ip /o/ni e )l! ( 1 dicr 17. S. (;eol. Sur'\v Prlof. (i nclud ing ig ad(oublt fully identified w~oim speci men).
Il:tir 112, p. 5'67, W1. Mt, ig. IV) "I, "M7 Miornt, Florida). ( 'Iipola, format ion (early Mliocenle), F~lorida.


Subgenus Dispotaea Say Of medium size, circular to elliptical in ventral plan.
Say, Acad. Nat. Sci. Phila. Jour., 1st ser., v. 4, p. 131, 1824. Protoconch of 14 to 1% rapidly enlarging whorls. Type (logotype, Olsson and Harbison, Acad. Nat. Sci. Phila. Shell smooth to a diameter of 3 to 6 mm. Shell at
Mon. 8, p. 276, 1953): Calyptraea costata Say, Miocene, that stage circular and apex central or subel)central.
Maryland. Sculpture consisting of heavy widely spaced radial
After describing Calyptraea grandis, Say remarked ribs, the interspaces bearing crude concentric lamellne, that it does not properly belong in the genus Calyplraea or consisting of closely spaced, generally narrower, and therefore proposed to place it in a newv genus roughened and pitted irregular ribs. Right side of cup
Dispotaea. He then assigned two other species to widely attached to interior of shell.
Dispolaea: Dispotaea lubifera, a new Recent species Maximum diameter 19.2 mm, height 11 mm (figured
from South America, and his previously described specimen). Maximnumn diameter 24.5 mm, height 14
Calyptraea costata (Say, 1820, p. 40; see p. 38 for nmm (largest specimenn. locality data), a fossil species from Upper Marlborough, Type: 518/190 Basel Natural History Musemn. Maryland, associated with others now known to be Type locality: Springvale quarry, Trinidad, SpringMiocene. The types of these three species evidently vale formation (late Miocene). are lost. So far as known Dispotaea tubifera has not Crucibulum springraleense is widely distributed in
been recognized. Calyptraea costata has been inter- the Gatun formation. Though the interior of the preted in different ways by Dall (1890-1903, pt. 2, Trinidad specimens, on which this species was based, is p. 349, 1892) and Martin (1904, p. 244, pl. 58, figs. unknown, the Crucibulum from Pananni is unequivo7a, b). Dall thought it is the strongly costate Cru- cally identified. Coarsely sculptured specimens have cibulum that occurs in the St. Marys formation of the external characters of a topotype of C. springMaryland and assigned it varietal rank under Cru- valeense kindly forwarded by Dr. Rutsch. Some fossils
cibulum auricula, the type of Crucibulum. According from Panain have only regular coarse sculpture, others to Martin, it is the weakly costate Crucibulum found only irregular generally finer sculpture, and still others, in the Calvert formation of Maryland. Martin's like the specimen figured, a combination of both. interpretation is reasonable in view of the locality cited This species has left no descendants in the Caribbean by Say and in view of Say's statement that the cup is region. It appears to be allied, however, to the attached by one side to the wall of the shell. At all Recent Panamic (,'rucibuh m pectinatum Carpenter, events Martin's identification is accepted. which has fewer ribs than the coarsely sculptured
Olsson and Harbison, apparently not realizing that typical form of C. springralense. (. pectinatumn ranges Say assigned the unequivocally identifiable Calyptraea from the southern part of the Gulf of California to grandis to Dispotaea, recently designated Galyplraea PanamA, possibly to Perl. costata as the type of Dispotaea. It is unlikely that Crucibulumn springraleen se is the
The cup of Dispotaea is attached by the right side, species Toula described as ('apulu~? gattnendis. At a or part of the right side, to the interior of the shell. diameter of 11.5 millimeters, the greatest diameter of The type species has a wide attachment area; Crucibu- the type of ('apulus? gatuncnsis., it should show traces lum grande has an attachment area of varied width. of strong sculpture, if it were the ( rucibuum. AccordThe Recent Crucibdulum striatunm (Say) (Nova Scotia to ing to a communication from D)r. Rutsch, who examined Florida), which has been cited as the type of Dispotaea the types of Toula's Gatun gastropods, the type of by several authors, has a consistently wide attachment Capulus? gaatunen esi. is an unidentifiable mold retaining area. parts of the inner shell layer. In the text Toula cited
Crucibulum (Dispotaea) springvaleense Rutsch figures 1 and 2 of plate 25 for Capuluts? gatanensis.
According to the explanation of the plate and the
Plate 19, figures 8-10 dimensions, however, figure 2 is his Capauas? sp.
?Capulus? galunensis Toula, K. k. Geol. Reichsanstalt Jahrb., Figure 2 quite certainly represents a mold of the Band 58, p. 692, pl. 25, fig. 1, 1909 (Miocene, Canal Zone). coarsely sculptured rucibuluamn that occurs in the Brown and Pilsbry, Acad. Nat. Sci. Phila. Proc., v. 63, p. 360, Gatun formation. Perhaps through this error in 1911 (Toula's record). citation Anderson was led to use the name (ruciba m
Capulus? sp., Toula, K. k. Geol. Reichsanstalt Jahrb., Band 58, tanner asee p. 692, pl. 25, fig. 2, 1909 (Miocene, Canal Zone). gatunense for that species. Crucibulum (Dispotaea) gatunense (Toula), Anderson, Calif. Occurrence: Lower, middle, and upper parts of Gatun Acad. Sci. Proc., 4th ser., v. 18, no. 4, p. 121, pl. 13, figs. 4-6, formation (middle and late Miocene). Lower part,
1929 (Miocene, Canal Zone, Colombia). .
Crucibulum? springvaleense Rutsch, Naturf. Gesell. Basel localities 137, 137a, 138, 3a, 139. Midle part, Verhandl., Band 54, p. 138, pl. 4, fig. 8, 1942 (Miocene, eastern area, localities 146, 147b, 147e, 147f (identifiTrinidad). cation doubtful, immature specimens only), 147g,


I-47h, 151, 1,52, 155, 155 ,i, 1551), 15;5(-, 151), 16() narrow en(ling lit It sniall callits lobe bearing a shallow
11411m, cf. westeni area, locality 162a. anterior depression. A narrow deep groove lies in front
.1 14 ale of wnb*l*ca1 rib and callus pad, separatism, theill fl-0111 Upper part, westel-11 .11-C.1, locality 185. Spi 11(rv. fol-Illatioll (late Miocelle), Ti-illi(41(1. 'Miocelle, Bolivar, border. Pariettal callits thiek, especially : v ill
Coloillbi"). front of junction with outer lip, where it forms a ridge.
Family NATICIDAE Oil iminature shells anterior part of parietal callus relaSubfamily NATICINAE tivelv Nvider than on mature shells and roofitio- over
Genus Natica Scopoli posterior end of unibilicus as it extends forwfird to join
UMbilical lobe. Operculitin tissitined to represent this Sc(qmfi, Tntroductio ad historioin iiaiuralein, 1). 392, 1777. species bearing a narrow nini-gliml rib, separated bY a T\ pe (lo-oty1w, ffiti-ris, Czit:tloguo of Mollusca ill the ?- z"n narrow groove froin a, secotid rib that is is narrow as
ritish Alusellill; pt. 1, Australasiaii, 1), 255, 1897); Ncrda
rilcllus Liiiii6, Peceiit, tropical westerii Pacific- the nianiiiil rib or sll(,-Iitlv Nvider.
1160-lit, 14.5 inin, diameter 1.5.2 inin (fi(rured mature Anton (1839, 1). 31) also desi,-,"iated Aerita rddbl' 1
specimen). Height, 9.7 inin, diameter 10.2 itini (figured tit(, I -,,Ile of A701ca, u t It imich earlier (late th'an Harris. zn
111111latilro specilliell).
Anton's desio-iiation, howo%'er' is of doubtful validity,
n TYpe: Acad. Nat. Sci. Phila. 3S46.
a it is a designation for Aatica Laimaivk. TYpe locality: Gatun Locks exca\-fltion, Canal Zone,
Subgenus Natica s. s.' Middle part, of Gattin forniatioll.
Tile type, the 1,11-crest of G ill the tYpe lot, is it sinall Natica (Natica?) species
The collecliolls fl.()Iil tho Iwarine Ineniber of the intinatitre shell (Itelght 9 millimeters). Oil the type and ot'llor ininiattliv sliell-, such as fliat, shown oil plate 20, Bohi0(?' fol-111,16oll zat, Vaillos Vaillos include two 3, tit(, anterior part of flie pal-ictal c"Illus Is Nvide naticid opercula tfiat hnxe a narrow marginal rib, zZ- aild roofs over the posterior end of the tinibilicus. Oil
sep.watvd 1) v a AwIlow lo-i-oo\ e from a widel. second rib. niatitre shells itiore of the ititibilictis is uncovered. Tile 'I'llov ropresejit, A'(tt,/'(,(/ ". S. 01' possibly some other ].1 r(,es
th"It, 11"Is It sinlihir operc I t, shell, which is incomplete, has a height of 19.5
111111n. Tfie lax-er Verv low-spired shells lulve an Inflated
pccinwn has ,I restored leii-th of about 12 illillillieters
shoulder, whereas sliells tluat liaxe "t higher spire have alld a width of 7.5 millinieters. Simill poorlv presel-ved It less itillated slioidder. Two sintill opercula assumed shells ft-oni locality 42 may represoiit, this species. -ei e found lit association with
to repres(- tit A'. lmbo \N
Occul-1-cricle: Marille 111olliket. of Bollio(") forill-ation shell, at loctilitv 1.55c and mother of niedium size at (I'Ite Hocelle or 0,11-ly 011gorene), localities 40, 40d, 42 locality 1-2. (identific"Ition dollbtfill).
Though Xatica 1)(Wits is faffly widespread 'it the Gatilit Natica .Natica'?) bolus Brown and Pilsbry foriliatioll, 0111Y a fe\\- specinions were collected at aiiv
locality, except, locality 10771). N. ywingi, front the Plate 20, fi-ure 1-3
Nhocene of the Doininicati Republic, reaches a someA'atira lwlas En)wti aml Pilshr v, Actid. Nat. Sci Phila. Proe., Whal hii ger size (holo-lit 24 miflinietei-s)j but, the
v. 61, 1). 508, pl. 22, fi- 9, 1913 (M ioceiie, Caiizil Zoiw). Z71
A'Wic(t !Iow ,qi M.-tury, Bull. Am. Palcoidology, v. 5, no. 29,1). 135 11111bilie'll o nd callus featilres, (Is Nvell as the 0111111w, of
P1. 23, ligs. 11, 12, l9t7 (Mioceiie, N. lwht,, AT. yoitngi fi-oin die Mlocene of Trinidad has
Pilsbry, Acad. -Nzit. Sci. Phila. Prov., v. 73, 1), 380, pl. 3-1, fig. .1 litiriower unibilicus aiid less conspictiolis 11111bilictil rib
21, 1922 (Mioeciw, Doniiiiicm 1)(-public Alatir v, Mill. Ani. than N. 1)olw,, it, is (oil, idered conspecific. AT. young Pnlowitology, v. 10, ito. -12,1). 239, pl. 40, fig. 4, 192.5 ('Ali(weiw, cocleatia Olssoii (1922, 1). 155, pl. 1,3, tir. S; Njiocene' Triijidad). Maiisfield, U. S. NMI. 'Alus. Proc., N'. 66, '111. 22, Costa Rica), however, has I, nat-row tit z tibilicits, Nveak
1). 57, 1925 (Aliocene, Triiii(la(l).
'Veltica ji0ti na l'ilsl-)r y :oid J4)hijsoii, Acid, Nat. '-,"ci. Phila. um bilical I-Ib, and lial-1-ower unibilicil c,(illiis lobe,, and I 1(,Iltl\- is not clos(,I\- rela.ted. All Nhocene spePnw., \'. 69, 1). 173, 1917 (Aliocelle, Doillillicall Republic). cVI(
Not A'Wico ymingi 'Maiir i \, 1J, (4-ol. Soc. Chitia llull., \-. 3, 1). cies front Costn Rica, V. millcri ('Fiabb (ISS I 1 1). 33S, pl.
2(;6, pl, Cj, figs. 17, 47; 11930 (Mioeclw, Pallmla B'Iy; Notica
11 44, fi-. 3) has a hi-ber spire and Nveaker unibilical rit).
'too*ffisciatet Lzininrck, fide Pilshry, Nat,. Sci. Phila. Proe., z- el
Y. castreooides IVoo(lr*ti(, (192S, 1). 377, pl. 30, fig. 5; S3, 1). 4:;2, 1931, 10,ceiit, Pawtni:I 13:1\1). 1 n
'\()t Notica Wioliitircs) cf. witiogi Nhur.y, Trechnialin, GeoL Al'tg.' Miocene, Jamaica) "I'lld its Recent Caribbean analog,
v. 72, p 550, pL 20, ti-s. :1 -5, 1935 (Mitweiw, ('tirriacou); N. ea4ren,, i,, Dall (IS89, 1). 293), have a wider and 1'oh'nic(s weaker 11111bilical rib and diiiiiier parietal callus. N.
( )f modluni size, thick-shelle(j, p'l-c vc,-Y I()\\- oI- bolu, appears to have no close I'ving allies in either el"lick- low, shoulder. sI Or '11flate(l. I),.()- Caribbean or Panalnic, waters.
locolich not cle'al-k- diffel-elittated fi-olll 1 etllalrider of 'I'lle. stron,,, tliou-h narrow, umbilical rib indicates
'11)[c.11 whol-I hil-e. (Tilibilicus wide, lillibilicni 1-ib I'llat, N 14 11- is not, (']oS('I\- related to AT. it


probably is to be assigned to an unnamed subgenus. (Woodring, 1928, p). 378). That view, which followed As pointed out by Powell (1933, p. 165), undue emphasis Iredale's (1916, p. 82) interpretation, is far fet ched. but on opercular characters in effecting a classification of has the same nomenclatorial effect as the view adopted naticids may lead to artificial alliances, in the present report.
Occurrence: Lower, middle, and upper parts of Gatun Natica s s., or naticids having similar opercula, occur formation (middle Miocene). Lower part, locality 138. in the Eocene (Harris and Palmer, 1946-47, p. 247, Middle part, eastern area, localities 142, 144 (incom- pl. 29, figs. 1, 2, 1947; Wrigleyv, 1949, p. 11, 13, fi-s. plete, identification doubtful), 147b, 147g, 155, 155a, 1, 2, 8-12). Naticari s, however, evidently (does not 155b, 155c, 157, 159; western area, localities 161a, 161c, antedate the late Oligocene. The late Eocene (Jack161d. Upper part, eastern area, localities 172, 173, 175, son) Nat;ca ptrmunda Conrad, which has been referred 176a, 177, 177a (incomplete, identification doubtful), to Naticariu. (Harris and Palmer, 194 ;-47, p. 246, 177b, 178. Cercado and Gurabo formations (middle 1947), lacks the axial grooves of that subgenus, and hias
Miocene), Dominican Republic. Springvale formation a less rapidly enlarging umbilical rib anid correspond(late Miocene), Trinidad. ingly narrower umbilical callus lobe. Xatlicari u is now
Naticarius Dumril found in western Atlantic and eastern Pacific tropical
Subgenus Naticarius Dumbril
and subtropical waters. The Mediterranean Y. milDuin6ril, Zoologie analytique, p. 164, 1806; genus without species. lepunciata Lamarek has a multirihhed operculum, sugType (monotype, Froriep, C. Dum6ril's analytische Zoologie, p.
gesting~ alliance within Xaticartius, but the ribs are very
165, 1806; quoted from Iredale, Malacol. Soc. London Proc., n v. 12, p). 83, 1916): Nerila canrena Linnd, Recent, West Indies. narrow and the shell has a narrow umbilical rib. This species has been erroneously assigned to Nacca Risso.
The status of Dum6ril's names, all of which end in been erroneously assi
cc. n urndentihied species of.Naticart us occurs ml thlelupper
"arius", will not be settled without a specific ruling, for An unidentified species of ca occurs in the uper
part of the Boluio formation and poorly preserved
they may be interpreted in various ways. According part of the Bohio formation and poorly reserved
Si fossils from the middle member of tihe Caimito formiato Opinion 148 of the International Commission on
g tion in the Gatun Lake area and the Culebra formation
Zoological Nomenclature, issued in 1943 .
are identified as Natica (aticaruii,?) sp. They have a
A generic name published as an emendation of an earlier name of relatively high spire and short axial grooves adjoining the same origin and meaning is to be rejected as a synonym of the Z
earlier name, and the type of the genus bearing the emended e sure. Teir umbilical features and oercla are name is automatically the same species as the type of the genus unknown. bearing the earlier name so proposed to be emended.
Natica (Naticarius) stenopa Woodring, n. sp.
Dumbril's names doubtless are emendations of earlier
names of the same origin and meaning. All of then Plate 20, figures -1-6
can be matched with earlier names that lack the "arius" Of medium size, thin shelled, moderately inflated, termination. He probably emended the earlier names whorls enlarging at moderate rate, spire high. Protowith the Latin suffix "arius"(pertaining to) as the name conch of 2% to 3 whorls, apical whorl small. End of of the animal; Naticarias, for example, being the name protoconch marked by slight change in texture of shell of the animal "pertaining to" the shell Natica. His and beginning of sculpture. Sculpture consisting of statement that "notre objet 6toit de faire connoiltre les short closely spaced retractive axial grooves, parallel to animnaux et non les couquilles que les revitent" supports growth lines, extending from suture and ending on that interpretation. In that event it could be argued shoulder on later whorls. Umbilicus moderately wide, that the names are to 1be rejected on the grounds that umbilical rib rapidly enlargiig, eding in a wide callus Dum6ril adopted a system that results in two names for lobe, the anterior part of which is concave. A very shell-bearing mollusks. If the names are to be accepted narrow deep groove in front of umbilical rib aild umnand are emendations, and therefore synonyms, is bilical callus lobe. Parietal callus moderately thick.
Naticarits a synonym of altica Scopoli or of Natica Operculhmn )earinig a mnargimial rib and 4 or 5 wid erfi t Lamnarck? If it is a synonymn of Natica Lamarck, it is ribs, all separated by deep grooves. available in place of that name, which is a homonym of Heightt 15.2 nun, diameter 14.8 mn (type). Height Natica Scopoli. Dum6ril's names, however, were not 21.5 nu1, diameter 19.5 nm largestt specimenn. admitted to be emendations when they were proposed. Type: USNM 561340: paratype, [5 5 11341:
prl)e-.T)pe: I >NiX[ 561340: paratype USNM[ 56t141, They therefore may be interpreted as entirely new paratypes >tanford Univ. names dating from his or Froriep's usage, depending on Type locality: 177b1) (USGS 5S54I, Mount Hope, ww ,t whether Dumeril's usage is considered nude. For the side of P1anama Railroad near oil tanks, Canal Zone), time being the view that they are new names is arbi- upper part of Gatun formation. trarily adopted. In 1928 Naticarius was regarded as a \tica 4seopa is widespread and locally common in substitute name for Natica Lamarek not Scopoli the Gatun formation, especially abundant in the upper


part of the formation in the eastern area. Eighteen age. N. precanrena F. Hodson (Hodson, Hodson, and
of the 21 lots, however, consist only of immature Harris, 1927, p. 68, pl. 36, figs. 2, 6, 9), a small Venespecimens, up1) to a maximum of 115 inirnature shells in zuehan early Miocene species (height 6.8 millimeters), one lot. The largest shells are imperfect. A shell of has a high spire, small initial whorl, and closely spaced iediin size from localitY 177c has an operculuin in axial grooves. It has, however, a higher spire and a place (pl. 20, fig. 6). An incomplete operculuni of wider umbilicus than small specimens of N. stenopa.
inediuim size, not associated with shlAls, was found Occurrence: Lower, middle, and upper parts of
ut locality 161. A small incomplete operculum, col- Gatun formation (Middle and late Miocene). Lower
lected at locality 162, has three ribs, an indeterminate part, localities 136, 137, 137a, 138, 138a. Middle number of other lower ribs being covered with a glaze part, eastern area, localities 146, 147b, 147g, 147h of enamel. The identification of this operculum is (incomplete, identification doubtful), 151, 155, 155c,
uncertain. The axial grooves disappear on the body 157; western area, localities 161, 161a, 161c, 161d, 170,
whorl of an incomplete doubtfully identified shell from 170a. Upper part, eastern area, localities 175, 176a, locality 14711. 177b, 177c; western area, localities 183, 185.
Though Brown and Pilsbry (1913, ). 508) recorded
t,. Genus Stigmaulax March A. canr:na from the Gatun formation and though
()lsson (1922, p. 155, pl. 13, fig. 9) figured a specimen M6reh, Catalogus conchyliorium * Comes de Yoldi, pt. 1, p. of that. Recent Caribbean species from the Gatun 3 8
Type (logotype, Harris, Catalogue of Tertiary Mollusea in the
formation near Gattn, that species is not represented British 1\Iusen; pt. 1, Australasian, p. 262, 1897): Natica in thle Gatun collections of the U. S. National Museum suleata Born (Nerita s.ih ata Born), Recent, West Indies. or Stanford University. N. stenopa is of mneduim size Stigniaulax, like Naticarius, lives in American tropical
and has a high spire, small apical whorl, closely spaced and subtropical waters on both sides of Central America. axial grooves and 5 or 6 ribs on the operculum. N. It is found in the late Tertiary of the same region, the
canlrena, on the contirary, is much larger and has more earliest species being of early Miocene age. inflated and more rapidly enlarging whorls, low spire,
large apical whorl, more widely spaced axial grooves, Stigmaulax guppiana (Toula)
more rapidly enlarging umbilical rib and correspond- Plate 20, figures 11-16
ingly larger umbilical callus lobe, and 8 Or 9 ribs o Natica guppiana Toula, K. k. Geol. Reichsanstalt Jahrb., Band the opercuilurin. 58, p. 696, pl. 23, fig. 6, 1909 (Aliocene, Canal Zone). Hodson,
(n h e basis of shell characters N. sten opa is closely Hodson, and Harris, Bull. Am. Paleontology, v. 13, no. 49, related to n. Recent Painic species idetiied by p. 67, pl. 36, figs. 1, 4, 1927 (Miocene, Venezuela).
Natica guppyana Toula, Engerrand and Urbina, Soc. Geol.
Dall as N. limacina Jousseaume (1874, p. 14, pl. 2, Mexicana Bol., v. 6, p. 130, pl. 60, figs .53, 54, 53 (reproducfigs. 7, 8). Jousseauine's description and illustrations tion of Toula's illustration), 1910 (Miocene, Mexico. Brown suggest that the ilentificat ion is erroneous. The and Pilsbry, Acad. Nat. Sei. Phila. Proc., v. 63, p. 360, 1911
operculuim of N. limacnin is unknown and the type (Miocene, Canal Zone). Olsson, Bull. Am. Paleontology, v. 9,
locality is indefinite: "West Indies(?)"''. Dall's N. no. 39, p. 156, pl. 13, figs. 13-15, 1922 (M\iocene, PananA, Costa iMca). Anderson, California Acad. Sci. Proc., 4th ser.,
limacina is represented inl the collections of thie U. S. v, 1s, no. 4, 1). 123, 1929 (XMiocene, Colombia). Tucker and National Museum bv one shell dredged in Panaimi Bay Wilson, Bull. Aim. Paleontology, v. 18, no. 65, p. 13, pl. 2,
at a depti of 33 fatliomus. N. .stenopa has a somewhat figs. 3, 4, 1932 (Miocene, Florida). Mansfield, Florida Dept. thinner shell, narrower groove in front of the umbilical Coiservation, Geol. Bull. 12, p. 10, 13 (lists), 1935 (Miocene, rib and umbilicl callus lobe, an wider umbilical Florida).
rib Natica (Ntigmaulax) sdrata guppiana Toula, Rutsch, Schweizer.
opening back of tlie umlbi1ical ib. Na/ticarioH opercula, Pulawnts Gessel. Ahh., Hand 34, no. 3, p. 51, pl. 1, fig.13 (type), ha ving 7 to 9 ribs, are represented by 2 lots front ls ( Miocene, Canan Zone).
Pauanu Bax- and also by lots dredged in the Gulf Natica (Naticarius) guppyana Toula, Oinonikado, Geol. Soc.
of C('alifornia off Guavimas and La PAz, but it, is not Japan Jour., v. 46, p). 621, pl. 29, fig. 18, 1939 (Miocene, kniowni that tle opelrcila are to be associated with Colombia).
Natica (Stigmiatulax) guppiana Toula, Gardiner, U. S. Geol.
Dall's N. luImrnu. They agree with the operculutil Sur(v Prof. Paper 142, p. 546, pl. 59, fig. 9 (reproduction of
of N. col ia Strong and Ifertlein (1937, p. 174, pl. 35, Toula's illustration), 1947 (Miocene, Florida). fig 12, 13, 16), dredged near Manzanillo, Mexico. Natica (Stigmaula.c) gappiana toulana Gardner, idem, p. 547,
A. collina, however, is tiin shelled anl(d has a very narrow pl. 59, figs. 7, 8, 1947 (1Miocene, Florida). iii it1 )ilica I rib andat small umbilical callus lobe. Natia (Stigmaulax) guppyana Toula, Marks, Bull. Am. Paleontology, v. 33, no. 139, p. 98, 1951 (Miocene, Ecuador).
Au/atica onr' (I or allied forms are widespread in the Opereulum (sp.?), Toula, K. k. Geol. leiehsanstalt Jahrb., ('a ribbaun region in forniations of Miocene and Pliocene Band 61, p. 511, pl. 31, fig. 26, 1911 (Miocene, Canal Zone).


Not Natica guppyana Toula, Li, Geol. Soc. China Bull., v. 3, spiral sculpture. The supplementary umbilical rib is
p. 266, pl. 6, fig. 46, 1930 (Miocene, Panama Bay; =Natica of variable strength, but is visible on shells of large and
elenae R6cluz, fide Pilsbry, Acad. Nat. Sci. Phila. Proc., v. 83, Inediun size.
p. 432, 1931, Recent, Panama Bay).
p. 432, 1931, Recent, Panaa Bay). Opercula are not rare. They were collected at 11
Large, thick shelled, spire low, whorls strongly localities, as many as 10 at a locality. A large shell inflated and rapidly enlarging. Protoconch of 2)4 to having the operculum in place (pl. 20, fig. 18) was 2Y2 whorls, apical whorl small. Sculpture of relatively collected by T. F. Thompson. The only other in place widely spaced retractive axial grooves, parallel to is in a minute shell, which has a height of 1.5 millimeters growth lines, extending away from suture and generally (locality 147b). Details of opercular sculpture are ending at or above periphery. On some shells they variable, especially the number of minor ribs. The extend to umbilical region, but not on last half of fine denticles on the very narrow marginal rib are body whorl of large shells. Umbilicus very wide, obscure on some large opercula. That the thick callus umbilical rib rapidly enlarging, ending in a moderately of the warty central rib conceals flat minor ribs, like wide callus lobe, the anterior part of which is concave those adjoining the central rib on some opercula, is on large shells and strongly excavated on shells of small shown by the mergence of such ribs on 2 large opercula, and medium size. On shells of large and medium size (pl. 20, figs. 13, 18). Toula described a small operculum a more or less distinct supplementary rib lies on un- without realizing that it belongs to a species he had bilical rib at its posterior border and may modify named. outline of callus lobe. Groove in front of umbilical Forms of Sti ulax loosely related to the Recet . Forms of Stiamaulaa: closely related to the Recent rib and umbilical callus lobe moderately wide on large Caribbean S. scaa (Born) are found in Miocene forshells, narrow on others. Parietal callus very thick. nations in Jamai ca, Haiti, the Dominican Republic, Operculum dominated by very wide thick warty central Puerto Rico, and Brazil. S. 'hlppiana, however, is rib. Marginal rib very narrow, denticulate. Several .
minor ribs, two of which generally are undercut along not one of them. It lacks gross spiral sculpture and is minor ribs, two of wuich generally are undercut alone more closely allied to the Recent Panamic S. broderi. more closely allied to the Recent. Panamnic S. broderitheir inner margin, hie between marginal and central
hir. inerm inr ie b e argly ag ent piana (Recluz), as pointed out by Olsson (1932, p. 207). ribs. Outermost minor rib irregularly roughened. S. broderipiana is smaller and has a less depressed
Height 33.5 mm, diameter 30.5 mm (figured large suture. The opercula of the two species are similar, specimen with short axial grooves). Height 30.5 nmm, but the central rib of S. broderipian a has a narrow crest. diameter 29 nmm (figured large specimen with axial S. elenaue (R6cluz), also a Recent Panamic species, is grooves extending from suture to umbilical region on another close ally. It also has a less depressed suture first half of body whorl), and its axial grooves are in general more closely spaced.
Type: Tech. Hochschule, Vienna (temporarily at The single available operculum has a narrower central
Geol. Inst., Univ. of Berne, Switzerland). rib. The color pattern, however, is the most distinctive
Type locality: Presumably Gatun Locks excavation, feature of S. elenae.
Canal Zone, middle part of Gatun formation. S. gappiana is found in the Gurabo formation of the
Stigmaulax guppiana is the most widespread and most Dominican Republic. A close ally of S. sulcatela also abundant of the Gatun naticids and was found in the occurs in the Gurabo formation, but not at the same Chagres sandstone at the mouth of Rio Indio. All of localities. This close ally of S. sulcata was recorded as the numerous large shells and many of medium size S. vererugosum (Cossmann) (Woodring, 1928, p. 383) have one or more healed breaks on the body whorl. and has been named Natica sulcata gurabensis by The more widely spaced axial grooves and the excavated Rutsch (1934, p. 52, pl. 2, fig. 10). S. guppiana also umbilical callus lobe differentiate very young shells occurs in deposits of middle and late Miocene age in from very young shells of Natica stenopa. The sculp- Florida. The collection from Shell Bluff on Shoal ture is variable. Shells of large and medium size on River (USGS 3742) consists of numerous specimens, which the axial grooves extend to the umbilical region all smaller than large shells from the Canal Zone. are common only in the tpper part of the Gatun forma- The collection also includes 3 opercula which agree tion in the eastern area. Locality 155c is the only with opercula of S. guppiana. Two specimens from locality in the middle part of that formation where all locality 3742 that have short axial grooves were named tbe specimens collected have grooves extending to the Natica guppiana loulana by Gardner. This is the umbilical region. No large shell has grooves extending common form in the lower and middle parts of the to the umbilical region on the later half of the body Gatun formation, and the numerous Gatun collections whorl. Though the body whorl of some large shells show gradation in the length of the grooves. The shows indistinct microscopic spiral lineation, like that single specimen (height 22 millimeters) from Vaughan on some specimens of Natica canrena, there is no gross Creek (USGS 12046) agrees closely with Gatun shells


of' niodium size that linvo (,rooves extending to the Operelillin, is lot, mentione(j. nougii flie opercultim umbilicnI repon. According to Tucker tand Wilson, of that speeles evidently is still unknown, there is iio
S. (111ppi ana m-curs In upper Nlio(-ene deposits at, Acline, reasonable doubt that Tectoitatica is an appropriate Florld(l. naDIV for the small American species. The type of
A Sti'(1,ma0ax 1'roni the hite Nliocene I'mita Cryptonatica (Dall, 1890-1903, 1). :362, 1892: type
Gavlhill formation of Vellezilela has, been described as (logotype, Dn1l, 1909, 1). 85): NWICa claww Brodcrip Natica (St i p/;, (I'll /(Ix) ,ml(wta kwunioldi Rutsch (1934, and Sowerby) is a large arctic and boreal species, oil 1). 50, 1)]. 2, fio-s. 6-8, pl. :1, fi-. 5). 1 ani itidebted to which 010 umbilical callus lobe completely fills the Dr. Riltsch for two topot vpes of this form. It is tallied umbilicus. Like flie small species, it has a smootli to S. gapp ?'(1 n (1, "Illd illay be considered a, subspecies of ealeareous operculum. When the aijatom v of the large S. lluppl Owl,. It Is collsldcr. Ibly Lirger flaill S. guppiatla tretic and small tropical species is kiiown, both names Proper (hei-lit, 42 indlimeters), but evell Oil these large (Teclovatica. mid (_!ryptonatica) may be found to be sholl'; Hie axial ("rooves colltilille to the 11111bille"ll I-c-ioll useful. almost to the outer 111). hirge form, S. giippi(tila T(Tionatieu. Ims bevii reeo,,,nized Ili the Eocene of
bcairmot-di', and tbe typical I'orm of S. gippiwna Ili the Enlolnnd (Wri-ley, 1949, 1). 14). (11,1-ros saildstolle are the last, Caribbean Alles of S.
Tectonatica species
Ocourreiwe: Lower, middle, aml upper ptirts of Two imperfect specimens record the occurrence
Gtitmi formlition (middle and Inte N'llocene). Lower of a small inflated species of Tl(lctmiatica in the late
part, localities E17, 137a, 1:18, 138a. -Middle part, Eocene or early Oliaocene strnta of Trini(Ind Island. eastern area, localities 142, 146, 147 (Identification The imbilicn]. callus lobe is preserved oil the smaller doubtful), 1471), 147f, 147g, 14711, 150a, 151, 153, 153a, specimen, but is absent (presumably dissolved) oil
Z7' I
155, 1551), 155c, 156, 1-57, 158 (identificitimi doubtful); the larger. The larger specimen bas a more strongly western) area, localities NU, 161c, 161d. Upper part, bulging body whorl than 7. agna. of the Gatun foriliaotistern nrea, localities 172, 175, 170, 170a, 177a,, 171b, t ioi i. T. flori'dava (Dall) (1890-190:1, pt. 2, 1). 366, 177c, 1"18; western arezl, loctilities 182, Mao 18:1, 185. pl. 17, fig. 5, 1892), of the varlY '.Nflocelie Tampa, 111110localitY 208. stone of Floridn, is more than three times as large and
C A,(,.res saildstolle (ctlrh Plimelle),
Mim-ene, Falc6n, Venezuela. Nliddle N'llocene, Bolivar is more elong.ite. Iferel(Jore 7. -goridana iv is the and Choc6, Colombia. Daule formation (middle, earliest recorded east, American specRIS.
X110("(11110), Ewmador. Middle Nlioeene, mi-theastern The larger specilliell Ims the following dillielisiolls:
P.mama all([ Costa Rien. Mlocene, Chlapis, Mexico. helig1lit, 2.4 inni, diameter 2.6 ilim.
Sltonl River formation (middle Miocene), Florida. Occurrence: Nt"Irille member of 1101110('?) formation
L"ite Miocene depo,,its af AcIliw, Floridn. Oate Eocene or e irl.v 011,,,-ocene), Gattin Lake area,
Genus Tectonatica Sacco bwnlit.y 42.
Sacco, Almi. Zoologia Anatoomia Cmnparata R. t'niv. Ttoriiio Tectonatica agna Woodring, n. sp.
P14d,, v. 5, it(). 86, 1). :33, 1,100. Plate 17, figure W
T vpe (mwmt1vj)1,): Tc4(twitic(i tcctol i Bors. (ern)r for Boll.)
lc(fo/a Bmiefli), Miocene zmd Plioco'ne, Italy. Verv Small, stroll- v hill'Ited, Spire low or moderately
Thimd) t1w 11,111le TC(lollatic(I Ims hoell uscd for s1will low. Protocollell liot cle.11.1v (Iltrerelitinted from reti-(qm,,d mcriczm specics (W omIrin-, 192S, 1). :;84), 111:1111der of, shelf, apic,11 whorl Small. I-111bilie'll cAltis (11.11 llswc wns Im l ('11111'eh, S,11*,4'w1m-v, hecoll'o Ito ]obo 111'ek, com pletelv fillill'o. 11111hilicus, bem.111(r a, SP IC111)(11111 ()f' I he I pe spect(I'll W0111 OX111111lied. Th 1-m l-11 celitr'd depression. I,d-c of 11111bilic.) 11111s
the lm ldlw ,,, (J J(dill Q. Bill-ch, of I'('s a "Iw(.1- lo1w roused above level of 11111bilic,11 border. I '-,11-1 v t al 111ch (d, X(111,(w t(vhd(l Identified 1) v Sat IS 11MV ti V11 11- ("11111" 1 hick. Oper(11111111 1111kilown.
1) 1 e. It 1 ; I tr-cr !I1,111 the Small tnqm-al Amencoll I h,[-ht, 2.8 min, dimneter 2.4 min (type). spccl(- (hel,-dit 7 millimelcr's; 111.immum hol-fill 12 TYpe: VSNNI 5613-4,S, jmrat.vp(-,, Stwif'ord Univ.
'11* 1 cim:ic, P'llmlim Rallmwh'l- ,, occmdmo ), 1() Sm-c(( :111d III(, 111libilical T i vjw kw illt.v: 1471) t "SGS
I(dw dlw, Iml cf)J11plolel v fill (he 11111bilicils'. leaving rood, almut 3,500 l'oet (1,065 meters') solithellst of < 11 11TM V 11111illcd "pocil, CM 111),11,01do 1() the 11;11.1-m vel- (;,Itllll rallro:1d ,tatloll, C,111.11 zolle), m iddle ])art of sp;wc (4 \ 1 1.1vill"'. \v*dt 11 m ] the"111.111 ("10111 I'm -111,16011.
S,]Y. III his Inler descriptiml (4 Th]s Immite Ttctml a like 111,111Y other small
S wc,) 1). '-d ) described the ()pol-cillmll w, czd- species 1'rom the Gatoll fornintion, is nbill](Illit at
C0rCMV,. ll'o wtt,; rek-111- on allied Recent loco I' I v 1-171), the tv1w locditx. The slizillow, but
slwcle." ns III 11P, decl lptlm) (11' V(I//,va Icchil(I Ow distillct, depression oil the 11111billcol cz1flus lobe Is its


most distinctive feature. On a few shells the suture Tihe type is an miniature shell (height 8.2 mnillimiet(ers). on the last half of the body whorl descends more The well-defined umbilical rib indicates alliance withI a
sharply than on the common form, producing a cor- Recent Caribbean species labelled IP. porcllanu.s
respondingly higher spire. (d'Orbigny) in the U. S. National Museum collection.
The more distinct depression on the umbilical callus The Recent species has a st rolnger rib and is less aplobe and the narrower groove at the outer edge of the pressed at the suture. ). (Collra(id) lobe differentiate Tectonatica agna from T. pusilla (Mansfield, 1930, p. 127, pl. 19, fig. 1), which occurs in (Say), which moreover is slightly larger. T. pusilla is the Duplin formation of North Carolina and in deposits the only fossil Tectonatica recorded from the Caribbean of late Mi\ocene age in western Florida, is larger, less region (Woodring, 1928, p. 384, pl. 30, fig. 12). It now appressed at the suture, and has a stronger rib. A late ranges from Massachusetts to Florida. A Recent Miocene species from Trinidad, )P. boultakoff Rutsch
West Indian species, possibly T. sagraiana (d'Orbigny) (1942, p. 139, pl. 6, figs. 7a, 7b), belongs in this group also lacks the callus depression. No Recent Panamic of species characterized by a st wrong umbilical rib.
species is represented in the U. S. National Museum According to Rutsch's illustrations, it is more inflated,
collection, less appressed at the suture, and has a deeper groove
Occurrence: Middle and upper parts of Gatun for- on the parietal callus.
mation (middle and late Miocene). Middle part, Occurrence: Lower middle, and upper parts of Gatun
eastern area, localities 146, 147b, 147f, 147g, 147h, formation (middle Miocene). Lower part, locality 151, 153a. Upper part, eastern area, locality 177c; 136a. Middle part, eastern area, Gatun Locks excavawestern area, locality 185 (identification doubtfull. lion (Brown and Pilsbry); western area, locality 1I61a.
Subfamily POLINICINAE tIpper part, eastern area, localities 177b1), 177c.
Genus Polinices Montfort Polinices brunneus subclausus (Sowerby)
Montfort, Conchyliologie syst6inatique, v. 2, p. 223, 1810. Plate 20, figure 9
Type (orthotype): Polinices albus Montfort (= Natica mamnillaris
Natica sobclausa Sowerby, Geol. Soc. Lo Lamarck=Natica brunn ea Link), Recent, West Indies.
p. 51, 1850 (Miocene, Dominica Republic).
Incomplete and poorly preserved naticids from the Poliniccs subclausa (Sowerby), Brown and Pilsbry, Acad. Nat.
Gatuncillo formation, the marine member of the Sci. Phila. Proc., v. 63, p). 360, 1911 (Miocene, Canal Zone).
Bohio(?) formation, and the Culebra formation are Miaury, Bull. Am. Paleontology, v. 5, no. 29. p). 136,
Spl. 23, fig. 14, 1917 (Miocene, Dominican Republ)lic). Olsson, doubtfully referred to Polinice. The umbilical fea- idem, v. 9, no. 39, p. 157, pl. 13, figs. 16-17, 1922 (Mliocene,
tures of these fossils, most of which are molds, are not Costa Rica, Canal Zone). Hodson, Hodson, and arris, known. idem, v. 13, no. 49, p). 69, 1)l. 36, fig. 5, 1927 (Iiocene, Jamaica).
Anderson, Calif. Acad. Sci. Proc., 4th ser., v. 18, no. 4, p. 124,
Polinices canalizonalis (Brown and Pilsbry) 1929 (MIiocene, Colombia, Canal Zone).
Polinices brnIica subela usa (Sowerby), Woodring, Carnegie Ist.
Plate 20, figures 7, 8 Washington Pub. 385, p. 385, pl. 30, fig. 13, 1928 (Miocene,
Natica canalizonalis Brown and Pilsbry, Acad. Nat. Sci. Phila. Jamaica); see this publication for other citations.
Proc., v. 64, p. 508, pl. 22, fig. 10, 1913 (Miocene, Canal Zone). ?Polinices (Mammilla) cf. brunnea Link, Weisbord, Bull. Am.
Of medium size, thick-selled. Body orl Paleontology, v. 14, no. 54, ). 29, )pl. 9, fig. 12, 1929 (Mliocene,
Of medium size, thick-shelled. Body whorl ap- Colombia).
pressed at suture, strongly inflated l)elow appressed
area. Aperture small for size of shell. Apical whorl Of medium size, thick shelled. Whorls strongly and
small. Faint microscopic spiral lineation visible on smoothly appressed at suture. Apical whorl small. unworn parts of shell. Umbilicus wide. Umbilical Umbilicus moderately narrow; umbilical rib almost flat.
rib strong on immature shells, somewhat flattened on Umbilical callus lobe narrow, slightly widened by u11111mature shells, ending in a wide callus lobe. Parietal bilical rib. Parietal callus very thick, bearing a shalcallus very thick, bearing a shallow transverse groove, low transverse groove.
Height 21 mm, diameter 18.7 mm (figured mature Height 20.3 nun, diameter 16.7 nun (figured specispecimen). Height 11 mm, diameter 10 mm (figured mnen).
immature specimen). Type material: British Mus., Natural History, Geol.
Type: Acad. Nat. Sci. Phila. 3844. Depart., Geol. Soc. London 12826 (6 syntypes).
Type locality: Gatun Locks excavation, Canal Zone, Type locality: Dominican Republic, Miocene.
middle part of Gatun formation. This Polinices is fairly common in the middle part of
Polinices canalizonalis is the least abundant of the the Gatun formation at locality 161c, west of Gatunm three Gatun species of Polinices. It also is the only Dam, and occurs at other localities, all in the middle one of the three that has a conspicuous umbilical rib. part of the Gatun formation. The groove on the


parietal callus is relatively deep on some small speci- Pilsbry, Acad. Nat. Sci. Phila. Proc., v. 83, p. 432, 1931, mens. The largest Gatun shells are half as large as the Recent, Panama Bay). largest from the Miocene of the Dominican Republic Polinices springalnsis Maury, Bull. Am. Paleontology, v. 10,
S(ano. 42, p. 241, pl. 40, fig. 6, 1925 (Miocene, Trinidad). and Bowden, Jamaica (height 40 millimeters), and are
much sminaller than large specimens of the Recent Moderately large, moderately thick-shelled, moderCaribbean P. bruneus proper (height 50 millimeters). ately slender to strongly inflated. Whorls not appressed Like the Miocene fossils from the Dominican Republic at suture, except near outer lip or on most of body whorl and Jamaica, the Gatun fossils have a slightly narrower of large specimens. Apical whorl small. Microscopic umbilicus than Recent shells of the same size. The spiral lineation distinct on unworn shells. Umbilicus fairly wide unil)ilicus of Weisbord's Polinices ef. P. brun- and umbilical callus lobe narrow. Parietal callus nca indicates, however, that the Miocene form cannotcon- moderately thick, much wider than umbilical lobe, sistently he d(listinguishled by the width of the umbilicus. bearing a faint to distinct transverse groove on imRecent shells that are not worn show a faint micro- mature shells. scopic spiral lineation, which has not been observed on Height 43.5 mm, diameter 33 mm (figured large
the fossils from the Canal Zone, the Dominican Re- slender specimen). Height 32.5 mm., diameter 28 mm public, and Jamaica. The apparent absence of linea- (figured inflated specimen). tion on the fossils, however, may be due to slight wear. Type: Cornell University 36931. A small form of P. brumineis subclawusus from the Miocene Type locality: Rio Cana, Dominican Republic, of Banana River, Costa Rica, has faint spiral lineation Gurabo(?) formation (middle Miocene). and also has a deep groove on the parietal callus, as ces sanisas-m ieri is the most widespread of
P tolinces RG 8/aGRsa,-7Nthdftr 1s the most widespread of
shown by Olsson's illustrations... .
shown oP by Olsso's illustrations. the Gatun species of Polinices. It is locally common in
A form of P.* bruneus subclausus that has a notch
between the Parietal callus and the umbilical callus lobe the lower part of the formation, but many of the specieen f. l n. mens are relatively slender, like that shown on plate 21,
s been rcognize(]d in the iocene of Venezuela and figure 14. The large figured specimen (pl. 21, fig. 13) Jamaica, and has been named P. subclausa larelana .
waS collected by T. F. Thompson. The umbihical rib is
F. Hodson (Hodson, Hodson, and Harris, 1927, p. 69, was collected b T. F.
pl. 36, fig. 8, pl. 37, figs. 12, 14). so flat that it is virtually absent. Therefore the narrow Pol. 36, fig. 8,tl. 37, figs. 1si Olsson (1932, p. 208, pl. 24, figs.14). umbilical callus lobe widens very slightly. The umbiliPolinices nelsoni Olsson (1932, p. 208, pl. 24, figs...
8, 10), whih is more slender th P. brnneus and has cus is of varying width on immature shells, and is practi8, 10), winch is more slender than P. brunneus and has .n
.i cally closed on one from locality 136 (height 6 mnillia narrower ambilicus, is a late Miocene Peruvian relative of P. brnne, but no close allies are known to b meters). The transverse groove onil the parietal callus is absent on shells of large and medium size, and generally living in the Panamic region. is int on small shells.
Occurrence: Middle part of Gatun formation (middle
Miocene), eastern area, localities 155b, 155c; western Differentiation of P. stanislas-meanieri renezuelanus area, localities 161 (imniature, identification doubtful) appears to be unwarranted. P. springalen sis is a 1610 161d, 170 (immature, identification doubtful). shouldered form of P. stanislas-meunieri, but is not much Cercado and Gurabo formations (middle Miocene), more strongly shouldered than the Gatun specimen Dominican Republic. Bowden formation (middle Mio- shown on plate 21, fig. 12. The early Miocene Costa
cene), Jamaica. Middle Miocene, Costa Rica. Mio- Rican P. em inuloides (Gabb) (1881, p. 339, pl. 44, fig. 4)
cene, Bolivar, Colombia. probably is related to P. stanislas-meainieri. The type,
and only specimen, is high spied; the umbilical area is Polinices stanislas-meunieri Maury not completely exposed; and the parietal callus is
Plate 21, figures 11-14 damaged.
P1.irS .P. stanilas-maeunieri is widely distributed in the
Polines .tani l, -mnrunri Alaury, Bull. Am. Paleontology,
v. 5, no. 29, p. 136, pl. 23, figs. 15-16, 1917 (Miocene, D)omin- -lOcene of the Caribbean region, but has no living ican li publicc. ()lsson, ide(in, v. 9, no. 39, p. 157, pl. 13, allies there. It is closely related, however, to the fig. 7, 1922 (Mio ene, Costa Rien). Maurv, idem, v. 10, no. Recent I anaminic P. vber (Valenciennes). P. stanislas4,2, p). 210, pl. 40, fig. 7, 1925 (Miocene, Trinidad). Anderson, we aeri is not much more than half as large, but its Calif. Aemd. Sci. Proc. 4th ser., v. 18, no. 4, p. 121, 1929 ) C,,1,,tm). p'arietal callus is thicker than that of specimens of P.
Mineene, Colombia).
tPoli i,iccs stani~aii ;. iatnS',ri / nO utlaona F. Hodson, Bull. Am. uber of the same size, indicating maturity. The outline
Paleontology, v. 13, no. 4), p1. 70, pl. 37, figs. 10, 15, 1927 of 1. stan islas-mneunieri ranges from strongly and (Miocene, Venlezuela). smnoothily inflated to moderately slender, whereas that of
No Poliniics t ir da-meuai(,i Maury, Li, Geol. Soc. China P uber is ore uniformly strongly and smoothly Bull., v. 9, p). 2(7, pl. 6, fig. IS, 1930 (Miocene, Panama Bay; be is Ore uniformly strongly and smoothly P ,or (Valeinciennes) and I'. rap dit limi Pilshrv, fide inflated.


P. coensis (Dall) (Mlansfield, 1930, p. 124, pl. 17, fig. Subgenus Glossaulax Pilsbry
8), which occurs in deposits of late Miocene age in west- Pilsbry, Nautilus, v. 42, p. 113, 1929. ern Florida, and P. robustus Gardner (1926-47, p. 550, Type (orthotype): Neverila reelusiana (I)Deshayes) (Natira pl. 59, figs. 5, 14, 1947), a middle Miocene form, are the reclusiana Deshayes), Recent, southern California to Gulf of representatives of P. stanislas-meunieri in the Miocene California. of Florida. P. coensis is smaller than the Caribbean The subgenus Glosswu lax embraes neverites that
species. It has a more distinct notch between the have a groove on the umbilical callus, dividing it into
umbilical callus lobe and parietal callus, thicker parietal anterior and posterior lobes. The groove of the type callus, and the transverse groove on the parietal callus species is located on the anterior part of the callus. persists to a later stage than on Gatun fossils. P. Glossaulax is widely distributed on both sides of the
robustus, which perhaps is to be considered a large high- northern Pacific and is represented in the Eocene of spired subspecies of P. coensis, closely resembles high- western North America by a typical species, N. secla spired Gatun shells, but has a thicker parietal callus. Gabb, which Stewart (1927, p. 325) suggested may be
P. coensis is the type of the subgenus Dallitesta Mfans- treated better as a subspecies of N. recl i ana. This field (1930, pp. 124, 125), which was proposed without subgenus formerly had a more extensive distribution. any discussion of differentiating characters. Perhaps It is represented in the Eocene of southeastern United it was proposed because of the distinct spiral lineation. States by N. lit la (Conrad) (Palmhner, 1937, p. 125, Should the genus Polinices be subdivided into sub- pl. 13, figs. 13, 14, 16, 19-22, pl. 80, figs. 13, 16), in the
genera, Dallitesta would be available for species that have Eocene of the Caribbean region by N. bolraren.vis a narrow umbilicus, virtually no umbilical rib, narrow Clark, and in the Eocene or Oligo(ene of Peru by N. umbilical callus lobe, and distinct spirallineation. There subreelusiana (Olsson). These early Tertiary species are, however, gradations from a strong umbilical rib, are hardly typical, as the umbilical callus groove is not like that P. canalizonalis, to virtually none; and many consistently present. Typical species, however, menspecies, including P. brunneus, the type of the genus, tioned under N. reclusiana x ena, are found in the have more or less distinct spiral lineation. Miocene of Florida and the Caribbean region.
Occurrence: Lower, middle, and upper parts of Gatun
Occurrence: Lower, middle, and upper parts of Gatun Neverita (Glossaulax) bolivarensis tapina Woodring, n. subsp. formation (middle and late Miocene). Lower part,
localities 136, 136a, 137, 138, 138a. Middle part, east- Plate 15, figures 7, 8, 11
ern area, localities 140, 146 (immature, identification Of medium size, depressed, conical. Umbilical callus doubtful), 147b (immature, identification doubtful), partly filling umbilicus, the wide unfilled space decreas147g (immature, identification doubtful), 147h (im- ing in width toward parietal callus, but extending to mature, identification doubtful), 155, 155c (incomplete, junction of umbilical and parietal callus. Parietal immature, identification doubtful), 157, 159a; western callus set off from umbilical callus by a faint groove. area, localities 161, 161c. Upper part, eastern area, Posterior part of umbilical callus bearing a faint groove. localities 171, 173 (incomplete, identification doubtful), Umbilical wall faintly striate. 177b; western area, localities 182, 182a, 183, 185 (im- Height 14.5 mum, diameter 19 nm (type). IHeight mature, identification doubtful). Middle Miocene, 16.5 mm, diameter 26.5 mmn (largest specimen).
Costa Rica. Gurabo(?) formation (middle Miocene), Type: USNM 561354. Paratype, USNM 561442.
Dominican Republic. Miocene, Bolivar, Colombia. Type locality: 40d (USGS 6028a, Gatun Lake area,
Miocene, Falcdn, Venezuela. Springvale formation lower bed at Yamos Vamos, off Palenquilla Point,
(late Miocene), Trinidad. Canal Zone, now submerged), marine member of
Genus Neverita Risso Bohio(?) formation.
Risso, Histoire naturelle des principales productions de l'Europe Though Necerila bolivarensis tapina is represented by m6ridionale, v. 4, p. 149, 1826. 12 specimens from the marine member of the Blohio(?)
Type (monotype): Neverita josephinia Risso, Recent, Mediter- formation, only a few show the callus features. The ranean Sea. callus is completely exposed on the type and paratype,
The Gatuncillo and Culebra formations, Emperador both of which have a relatively wide unfilled umbilical
limestone member of the Culebra formation, and the space, a faint groove between the umbilical and parietal
La Boca marine member of the Panami formation callus, and a faint groove on the posterior part of the
yielded molds of low-spired naticids identified as umbilical callus. The groove on the umbilical callus Neverita? sp. A large low-spired naticid from the of the type probably is modified by an artificial crack. marine member of the Bohio(?) formation near Palen- The paratype has a shallow groove that disappears
quilla Point (diameter 39 millimeters), the umbilicus before reaching the umbilical border. Enough of the of which is not exposed, also is identified as Neverita? sp. umbilical callus is exposed on two other specimens to


show t hat, a1 considerable part, of the umbilicus is not cuspidata (Guppy) (Maiirv, 1925, p. 239, pl. 40, figs. filled. 9, 10; 'Rutsch, 1942, p). 140; Sprinigvalc formation,
TIIils nieverite is considered a subspecies of AN. boli- Trinidad). N. chipolana has a short anterior callus
cr ui Clark (Clark and Durham, 1946, p. 16, 1)1. 15, lobe; N. qub porcava has a narrow anterior lobe and the I -ii-s. 10, 11, 14, 15, 18-20, 22, 26)-a subspecies charac- posterior lobe leaves part of the umbilicus unfilled; A I erized bY its depressed ouitlinle and wide umubihical space cuspidala is very large (height 60 mmn) and has short gradually taperig toward the p~arietal callus. The subequal lobes. There are no living species of Glossauspe('cimeni of N. bo~ ~ proper shown by Clark on lax in the Caribbean Sea or elsewhere in the western
plate 15, figure 11, is depressed and has a wide umbilical Atlantic. The late Miocene N. cuspidata is the last sJ)flce. The umbillecad space, however, separates the Caribbean species. callus from the entire, umlbilical wall. AT. bolivarellsts Inasmuch as N. reel usiana has a long history in the proper occuirs inl the late Eocenec of Colomnbia. It and eastern Pacific going back to time Miocene, if not earlier, ie( sumbspecies from iP~amui are related to A. sub- AT. reelasiuna xena znevidently' is a migrant from the
I((u~Iha(Olssoni) (1931, p). 6S, 1p1. 10, figs. 1, 4), of P~acific. The present distribution of N. reclwsiaita and
helae oen o ery 1 goee hia hleofP -i its allies, which are not fodind south of the Gulf of
That, species has a ighI spire and practically filled1 California, shw arked reduction since Miocene
ii ubiliustime.
Occurrence: Mfarfie member of B1ohio(?) formation Occurrence: Lower and middle parts of Gatun for(late ~ ~ r i(iei rery0 gcn) au ae~a nation (middle M\iocene). Lower part, localities 136a,
locaitis 40 40, 40, 4 (im atue).137, 137a. Middle part, eastern area, locality 155.
Neverita (Glossaulax) reclusiana xena Woodring, n. subsp. Subgenus Hypterita Woodring, n. subgen.
Plate 2 1, figures 5, 8, 9Type: Nultica hijcoides Gray, Recent, Baja California to Perm.
Of mnedim size, generally low spired. Spiral lineatioti ~Z 1iill onuiiia al u o lehrp' pterita is proposed for neverites that are greatly
sumab~~llv duieto sl(iht weari. Post erior lobe of umbilical -(lepressed, anid have a very wide umbilicus with gently
cals ogr hnaneir oe rahZguuiia sloping wall, a thin umbilical callus lobe perched on a
I- 1 narrow or moderately wide umbilical rib, and a very
wall umb bten nlilical wallit andro oreio lobenarr thini wash of parietal callus. This well defined group
of ubilcalcalls nr~o or erynarow.of meverites includes only two known species: the type
hfelit 25 imm, diameter 27 mm11 (type). Height 34
n I-,daee i clulte 5m m(iue lreIiil species andl the i\ liocenie Caribbean Nererita, icreidis.
sirei td s~~iaeer(ii). ee:5mn(fgrdlag ih The type species is generally known as ANcrerita glauca
Type: USNMI 5618355; paratypIes, Stanford Ui (eso)
T ype locality: 137 (USGS 16911, Tranisisthinian Neverita (Hypterita) helicoides (Gray)
llighwa-fY, 1.7 kilometers northwest of Sabanlita, latia- Plate 18, figures 15, 16
itna), lower part, of C"at un formation1. 7A\t(ica pabdai(~ B. Sowcerby, Zool. Jour., vol. 1, p). wO, pl. 5,
N [Ynrta reelu,5WUtw zct(iU I..base,(l oii 12 speciniens from fi. 4, 182-1 (Recent, locali'ty unknowin, but another specimen I lie lower part of the G"atun format ion and one front the citedl as South Amierican) Barnes, Lyceum Natural History ma dle art It is remiarktiblY slitilar to a small formn New York Annals, vol. 1, 1). 1:36, 182-1 (Recent, Perd). Not of X. r-clastatia, (I esh.av\es) found along'), the outer X alica puluala .J. Sowerby, 1822.
coas. ofBaja( 'aiforia nd aong he Glf O C'd Naico Iu'1icoide.s (ira v, Zool. .Jour., vol. 1, 1). 511, foot note, 1825
~riii. I e at inneer te nerahsaiarwr citedd as miainiscript name of Barnes).
fora. he atm ioveiteil geera ha aiiarox i er Nalica (/1(1 On "lluiii1boldt"', Le ssonm, Voyage, aut our u lIm(e I twelteublcl aladteau ro monide a Coquille ,Zoologie, vol. 2, pit. 1, p. 369,
c'a hits lo be. Some small Recent shells, howev-er, arie pl. 11, figs. 1, 1', 18301 (Recent, PerI). p)ral ct I call illd istinlgisliable from the fossils. This Na lira boo plandi Vale, cienntes. in Humboldt and Bonipiand,
exi~t i frm is hetilised s vaietv o N.~. Voyage :oix regions eqinoximles du nouivcau continent, pt. 2,
cliI~lIJ (PilbrvandI AWC, 9321).126 1 it ts t ~Recucoil d'observations de zoologic, vol. 2, 1). 264, pl. 57, is nlot Vet, sat isi :act orilx- (let erined. figs. 3(1, 31), 1832 (Rceneit, Acapulco, Mexico; not seen).
?Ncrcrila nercidis MAaury, (A)sson, Bull. Am. Paleontology, vol. 9, FN'picalI species of (do'Szav/ax tire found inl tie( Miocenie no. 39, p). 158, 1922 (Miocene, Costa RiBica).
of llidta atid( the ('ari Ibeaii region: AN. c/i ipolana Painiiccs (.Vri'v'r1) yqia umboldt (Jlsson, idem, vol. 27, no. I )all ) (Ga mdiwjr, 1926-47, p). 551, 1)1. 59, fig. 22, 1947; 106h, p). 20 (list), 1942 (H1 ocene, ( lost a Menc).
t, Pollitcs het jeo ides ((,ray), lierticin and Strong, Am. Mlus.
(,'hIi pola format iouil, Florida), AT. s bporcaita (Fi. I Iodson) Nat ural H ist ory Bull., vol. 107, art. 2, 1). 287, 1935 (Recenit, (IIldsmti, Ii 0(1501, anid 11 arris, 1 927, p). 70, pl. 36, fig. 3, Biaja California to P'r6; se*e this pub~licat ion for ot her pl1. 37, figs,. 5, (9, 16; \ Iioceiie, Veniezuela), anid AT. citations),


Of medium size. Microscopic spiral lineation of Caimito and Culebra formations include unidentified fresh Recent shells not apparent, presumably due to species of Sinm, represented by poorly preserved specislight wear. Umbilical rib narrow, slowly enlarging; mens. The Culebra Sin ttun mnay be the species from unfilled umbilical space wide. the Anguilla formation, of the island of Anguilla, reHeight (incomplete) 16 mmn, diameter (incomplete) corded as Sinut chipolapnm (D)all) (Cooke, 1919, p. 34 mm (figured specimen). 124, pl. 5, figs. Ga, 6b), but the species so identified is
The Gatun formation yielded three incomplete fossils smaller and more depressed than S. ciipulanum.
that closely resemble Recent shells of Nererita helicoides A species from the Gatun formation, Sin gatfaense of medium size. The largest fossil, if it were complete, (Toula) (1909, p. 697, pl. 28, figs. 3a, 31, 3c) is not would have a diameter of about 45 millimeters. The represented in the collections examined. It was corlargest Recent shells of N. helicoides in the U. S. pared by Toula with the Recent West Indian S'. perNational Museum collections have a diameter of specir un (Say) and, cording to his illustrations, is
between 55 and 60 millimeters. Slightly worn Recent closely related to that species and the Recent Panamic shells do not show the very fine slightly wavy micro- S. noycsi Dall. Toula's species is greatly depressed and scopic lineation of fresh shells, has a very narrow base. S. gatunense has been recogNererita nereidis Maury (1917, p. 137, pl. 23, figs. nized in the Cercado formation of the Dominican 17, 18), which occurs in the Cercado formation of the Republic (Alaury, 1917, p. 138,. pl. 24, fig. 2) and in Dominican Republic, is closely allied to N. helicoide. the Bowden formation of Jlamaica (Woodring, 1928,, p. Like the Gat in fossils, it is smaller than N. helicoides 390, pl. 31,. figs. 3, 4). N. dodon tmi Gardner (1926-47, (diameter 35 mm). Moreover it has a wider umbilical p. 554, pl. 59, figs. 37, 39. 1947), of the Oak Grove rib than the Recent species. However remarkable it sand member of the Shoal River formation of Florida,
may be to recognize two very closely related species of probably is a large form of S. gatunense. Though Hypterita in the 'Miocene of the Caribbean region, the Toula's illustration shows no faint spirals on the base, Gatun fossils are identified as N. helicoides on the basis some specimens of the species from the Dominican of their narrow umbilical rib. Republic and Jamaica identified as S. galunense have
The fragment from the Miocene of Banana River, faint basal spirals like those on the type of S. dodonum.
Costa Rica, identified by Olsson as N. nereidis, is not
accessible at the present time. A fragment from that Sinum euryhedra Woodring, sp.
area, however, in the collections of the U. S. National Plate 21, figures 4, 7, 10
Museum has a narrow umbilical rib and is doubtfully ,inrn species, Woodring, Carnegie Inst. Washington Pub. 385, identified as N. lielicoides. p. 390, 1928 (Miocene, Jamaica).
Gray's name is far from satisfactory. He cited it as Of medium size, imo(derately depressed, base relatively Barnes' manuscript name, a name that was still-born very wide. Protoconch consisting of about 11 smooth so far as Barnes' mention of it is concerned. Unfor- whorls. Spire whorls and body whorl between peritunately the name, as Gray's name, is nomenclaturally phery and suture sculptured with spiral bands, sepaavailable and therefore, as pointed out by Hiertlein rated by grooves that, for the most part, are of about and Strong, replaces the well known name Nee rita same width as the bands, but near suture are twice as
glauca. wide as the bands. Base smooth except for exaggerOccurrence: Lower and middle parts of Gatmun for- ated growth lines. A narrow groove lies behind posmation (middle Miocene). Lower part, locality 136a. terior part of everted colunellar lip. Middle part, eastern area, locality 155b; western area, Height (incomplete, spire crushed) 11 mm, diameter locality 161c. Middle Miocene, eastern Costa Rica (incomplete) 27 mmn (type).
(identification doubtful). Pliocene, western Costa Rica. Type: USNM 561441. Recent, Magdalena Bay, Baja California, and Gulf of Type locality: 137a (Stanford University locality
California to Perdi. 2655, Transisthmian Highway, 1.7 kilometers northwest of Sabanita, Panami; same as USGS 16911),
Subfamily SININAE lower part of Gatun formation.
Genus Sinum Rdding The type, an incomplete and somewhat crushed speciR6ding, Museumn Boltenianuni, pt. 2, p. 14, 1798. men collected from the lower part of the Gatun formaType (logotype, Dall, U. S. Natl. Mus. Bull. 90, p. 109, 1915): tion by T. F. Thompson, is the only representative of Helix haliotoidea Linn6 (cited by R6ding as Helix haliotoidea this species. It is characterized by moderate depresGmelin), Recent, western Pacific(?). sion, wide base, and strong sculpture. Owing to crushThe collections from the Gatuncillo formation, the ing, the spire is too low in apertural aspect (pl. 21, marine member of the Bohio(?) formation, and the fig. 4).


There are no known close allies of this species in Occurrence: Middle and upper parts of Gatun formaCaribbean and Panamic waters. S. tnaculatut (Say), tion (middle Miocene). Middle part, eastern area, a Recent Floridian and West Indian species, has a localities 147b, 155, 155a, 155b, 155c (very small), 157.
narrower base, thinner coluhmellar lip and parietal Upper part, eastern area, localities 175, 176, 177c.
callus, and( weaker sculpture.
The small incomplete Sinan from the Miocene of Subfamily GLOBULARNAE
Jamaitica, so far as it goes, has the characters of S. Data concerning the anatomy of Cernina fluctuata eur(/hedra. (Sowerby), the only surviving globularine, are desirable
Occurrence: Lower part of Gatun formation (middle as a basis for consideration of the subfamily or family Miocene), locality 137a. Bowden formation (middle status of that species and its numerous fossil allies.
Miocene), Jamai(a. Wrigley (1946, p. 88) has proposed a useful terminology for features in the umbilical region and on the
Sinum gabbi (Brown and Pilsbry) columellar lip of globularines. The sheath (the limbe
Plate 21, figures 3, 6 of French authors and the callus or fasciole of American
authors) is the shell layer emerging from the umbilicus Sigan.yts (Es Uaticim) p db)i Brown and Pilshry, Acad. Nat. Sei..
Phila. Proc., v. 64, p). 509, pl. 22, fig. 13, 1913 (Miocene, of umbiicated species. Its outer edge is designated Canal Zone). the rim. The downward extension of the parietal
?Ninu qu irosmi urnt F. Iodsonii, Bull. Am. Paleontology, v. 13, callus, overlapping the sheath, is designated the lobe
no. 49, p). 67, pl. 36, figs. 10, 12, 1927 [Miocene (Oligocene- of the columellar border, or simply the lobe. The Miocene of Iodson), Zulia, Venezuelal. outer edge of the lobe, where it overlaps the sheath
Reaching a large size, not depressed, body whorl below the umbilicus, is either fairly sharp or indefinite.
strongly inflated. Spire low or relatively high. Proto- The sheath of some nonumbilicated species, such as couch of 2/ smooth slowly enlarging whorls. Sculpture Globularia sigaretina (Lamarck), is as well defined as of narrow closely spaced spiral threads of two or three that of umbilicated species, but the umbilicus is repreorders. Spirals of early whorls variably crinkled by sented only by a slight depression at the posterior end growth lines. A very narrow umbilical groove lies of the sheath, formed by the outer edge of the lobe.
behind posterior part of everted columellar lip of adult On other nonumbilicated or narrowly umbilicated shells. Immature shells umbilicate. species a sheath is not recognizable. If present, it is
Height 23 mm, diameter 23 mm (figured specimen). concealed by the lobe, which forms an everted columellar Height 27 mm, diameter 24 mm (largest complete lip that has an outer edge as sharp as a rim.
specimen). Estimated diameter 35 mm (largest speci- Genus Globularia Swainson
Genus Globularia Swainson
men, incomplete).
Type: Acad. Nat. Sci. Phila. 3845. Swainson, A treatise on malaeology, p. 345, 1840.
Type locality: Gatun Locks excavation, Canal Zone, Type (logotype, Ilerrmannsen, Indicis generum malacozoorum,
middle rt of Gatn formation. v. 1, p. 480, 1847): Natica sigarctina Larnarek, Eocene,
middle rt of Gatun formation. Paris basin.
The type is a very small shell 6.5 millimeters high. Subgenus Globularia s.s.
The largest complete specimen (height 27 mm), colGlobularia (Globularia) aff. G. fischeri (Dall)
lected at locality 175, has a higher spire than the others,
buit is associated with a smaller low-spired shell. That Plate 15, figures 9, 17, 18
this sl)ecies reaches a considerably larger size is shown Moderately large, weakly shouldered, greatly inflated. by half of a body whorl (locality 176), which indicates a Spire low, turreted. A narrow sloping shelf lies bediamleter of about 35 millimeters. The Venezuelan tween suture and shoulder. Aperture greatly expanded.
S. q(1irostuini is snitall, agreeing with S. gabbi in outline Sheath moderately wide on inmutature specimens. Posand sculpture, and 1may rel)resent a small early Miocene terior part of lobe well defined on immature specimens. race of S. g(abb;. S. nol oi Mau y (1917, p1). 139, pl. Umi)ilicus closed. 24, fig. I1), a species 1 hat occurs in the Ginraho formation leighlit (almost complete) 35.5 mn, diameter 31 mm of t he 1) minican Republic, is more inflated than S. (large figured specimen). Height 18.5 am, diameter ga(bbi. (incomplete) 15.5 mm (small figured specimen).
S. qabbi is a nondep dressed species related to the This greatly inflated G(Ilobularia, rel)resenited by more
Recent Peruvian S. cowarcuern (iuxiarck), the largest or less incomplet and poorly preserved specimens from species of the genus (height 48 nn). The fossils, the middle member of the ('aimito formation of the
except) thie high1-sl)ired specimnel, have a similar outline, Gatlun Lake area and the Culebra formation, is closely but have sl)irals of less uniform width. No similar related to Globulariafischeri (Gardner, 1926-47, p. 556, species is living in the western Atlantic. pl. 59, fig. 28, 1947). G. fischcri occurs in the Chipola