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STATE OF FLORIDA DEPARTMENT OF CONSERVATION S. E. RICE, Supervisor of Conservation Herman Gunter, Director, Geological Survey GEOLOGICAL BULLETIN NO. 21 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA By ROBERT 0. VERNON, Ph.D. Assistant Geologist, Florida Geological Survey Prepared in cooperation with the Louisiana School of Geology Published for THE STATE GEOLOGICAL SURVEY Tallahassee, 1942 SS7.59 Ft, 3'o- t or 08 w .f >44 '41 0* Ok 3, 03 8, .L zh; d- ws t r j LETTER OF TRANSMITTAL Tallahassee, Florida July 1, 1941 Honorable S. E. Rice, Supervisor of Conservation. Sir: I have the pleasure of transmitting Florida Conservation Depart- ment Geological Bulletin No. 21, entitled, "Geology of Holmes and Washington Counties, Florida," by Robert O. Vernon, Ph.D., As- sistant Geologist of the Florida Geological Survey. This is the first detailed geological study of counties in Florida, and presents the physiography, stratigraphy, and economic geology of Holmes and Washington Counties. Geological studies in other counties are planned and should bring new wealth and industry to Florida, develop cultural interest in geology, and aid in the inter- pretation of the geological history of the state. Herman Gunter, Director Geological Survey. TABLE OF CONTENTS PAGB F orew ord ......... .. ........................................................................................ x A abstract ........................................................................... .......................... ............ Introduction ............................................................................................. 1 L location ................................................................................. .... 1 Maps ........... .......... ................. ............. 1 Indian Occupation ......................... .............................................................. 2 Utilization of Resources and Present Classification ............................. 3 Physiography .... ......................................... ....................................................... 5 Introduction ...... ...................... ....---------- .......................................... ........... 5 River Valley Province ...................................................................................... 5 Choctawhatchee River ............................................................................... 6 Flood plain ................................... ................................................. 6 N natural levees ...................................................................................... 8 Rim swamp streams ......................................................................... 8 Tributaries to the Choctawhatchee River ................................. ....... 9 Stream Terraces .......................................................................................... 9 10-20 Foot Surface ................................................................................. 13 30-50 Foot Surface ......................................................................... 14 60-100 Foot Surface ............................................................................. 14 145-165 Foot Surface ............................................................................ 15 Coastal Plains Province ............................................................................................... 15 C coastal Surfaces ................................................................................................ 15 Introduction .............................................................................................. 15 5-30 Foot Surface .................................................................................... 19 60-105 Foot Surface ....................................................................... 21 115-150 Foot Surface .............................................................................. 23 170-220 Foot Surface .............................................................................. 24 250-320 Foot Surface ...................................................................... 24 Summary of Terraces ................................................................... 25 O rigin of Terraces ........................................................................................... 26 R regional U plift ............................................................... .. ................................. 28 Steepheads ............................................... .......................................................... 28 Limestone Sinks ............................................................................................ 30. Stratigraphy ...................................................................................................................... 33 Introduction ........................................................... ......................... ............... 33 Maps and Sections ............................................................. ......-....--.. 36 E ocene Series ............................................................................................................ 40 Jackson Group ...........................................................................-.......... 40 Ocala Lim stone .......................... ................................................... 40 Historical summary ................................................................ 40 Physiography and outcrop pattern ...................................... 41 Character of materials .............................................. 42 Thickness and structure ................................... ......... ....-..... 42 Paleontology ........................... .... ............................ ...-- 43 Local details ............................................ ................... 43 Oligocene Series .......................................................................... 51 Vicksburg Group ...................................................... -........- 51 Marianna Limestone .............................................................. 51 Historical summary ...................... ...... .................... ...- 51 D definition ......................-..................... ..... ............ ............ 51 Outcrop and physiography ........................................... 51 Lithology ............................... .......-.--.----------- ------------------.. 52 Thickness and structure ..........................................-- ...... .. 52 Paleontology ...................... --------------------------------------.... 52 L ocal details ............................................................. ............. 53 PAGE Suwannee Limestone .............................................................................. 55 Introduction ............................................................................... 55 Historical summary ................................................................... 50 The Suwannee limestone in Holmes and Washington Counties ..................................................... ............................... 57 Definition ........................................ .......................................... 59 Physiographic expression and outcrop ................................. 59 Lithology ...................................................................................... ... 59 Thickness ..................................... ............................................... 59 Structure ......................................................................................... 59 Paleontologyy .............................................................................. 60 Local details ............................................................................. 60 M iocene Series .................................................................................................... 67 Tampa Formation ...................................... ........................ 67 Historical summary ................................................ ............. 07 D definition ......................................................................................... 68 Outcrop and physiographic expression .................................... 08 Lithology and thickness ............................................................. 68 Structure ....................................................................... ..... 69 Paleontology .............................................................................. ..... 69 Local details ............................................... ...................... 70 Alum Bluff Group .......................................................................... 73 Historical summary .................................................................. 73 The Alum Bluff group in Holmes and Washington Counties 74 Outcrop and physiographic expression .................................. 75 Lithology ............................................................................................ 75 Thickness and structure ...................................... ............ 76 Paleontology .......................................... ........ ..................... 76 Local details ................. ................................................................. 77 Choctawhatchee Formation ............................................................... 96 Historical summary ................................................................ 96 The Choctawhatchee formation in Holmes and Washing- ton Counties ........................................................................................ 97 Outcrop- and physiographic expression ................................... 97 Lithology ................................................................. 98 Thickness ...................................................................................... .... 98 Structure ................................................... ........................... 98 Paleontology ................................................................................... 99 Local details ......................................................... 99 Post-Miocene Stratigraphy ......................................... .......................... 128 Historical summary ........................................................... ...... 128 Introduction and general lithology ............................................ 129 Silicified boulders ............................................................................ 130 Pliocene? or Pleistocene Series ........................................................................ 134 Deposits underlying the 250-320 Foot Surface .......................... 134 E exposures ...................................................... .............................. 134 Pleistocene Series ........................................ .. ................................ ........... 135 Deposits underlying the 170-220 Foot Surface and the 145-165 Foot Surface ................................................................................... 135 Exposures .................................................... ..... 135 Deposits underlying the 115-150 Foot Surface and the 60-100 Foot Surface ..................-... .......---------------................. ..... 137 Deposits underlying the 60-105 Foot Surface and the 30-50 Foot Surface ....................................... ......................................... 138 Deposits underlying the 10-20 Foot Surface ................................ 139 Recent Deposits ..... ................................... 140 Economic Deposits ...................................................................................... 142 Clay ................... .............................------------- ----------------------- ---------------- 142 Sand and G ravel ..................................................................................................... 143 Limestone ...................................................................................... ... 143 Water Resources ................................................................................................... 144 Petroleum Possibilities ....................--. .....- ..-- ....-....... .......................... 144 Selected Bibliography ..................................... ................................................... 146 Index ................................................ ........................................... .. ... .............. 154 vi ILLUSTRATIONS PAGE Frontispiece-The coastwise 115-150 Foot Surface, two and one-half miles south of Greenhead, Washington County ............................. ii Plate I Geologic map of Holmes County-In pocket II Geologic map of Washington County-In pocket Table 1 Chart of fluvial terrace characteristics ................................ 12 2 Correlation of Pliocene or Pleistocene surfaces showing possible equivalents ..................................................... 18 3 Table of geologic formations in Holmes and Washington Counties ................................................. .......................................... 34 4 Faunal checklist of the Ocala limestone ................................ 47-50 5 Molluscan faunal checklist of the Alum Bluff group ........ 87-95 6 Molluscan faunal checklist of the Choctawhatchee form ation ...........................................................................................111-120 7 Foraminiferal checklist of the Alum Bluff, and Choctaw- hatchee, M iocene ..................................... ...................... .............121-127 8 Summary of the characteristics of the various Pliocene or Pleistocene deposits, marked by definite levels .................. 141 Figure 1 Drowning of the lower part of Holmes Valley, resulting from high floodplain deposits along the Choctawhatchee R iver .............................................................................................. 2 Bounding scarp between the alluvial 30-50 and 60-100 Foot Surfaces ....... ............................................................................... 3 Generalized and diagrammatic profile across the Choctaw- hatchee River in central Holmes County .............................. 4 Partial restoration of the 60-105 Foot Surface, separated from younger and older surfaces by seaward facing es- carpm ents ....................................... ............................................... 5 Recent beach and dune ridge, near Panama City, Florida .. 6 Diagrammatic profile of beach ridge and sand dune ac- cumulation on the 5-30 Foot Surface .................................... 7 Drainage patterns, and ridges of southern Washington County ............................................. ....... ..................... .. 8 Escarpment separating the coastwise 60-105 Foot Surface from the 115-150 Foot Surface ............................................. 9 A steephead ................................................................................ 10 "The Deadens", a prairie ................................................ 11 Porter Pond, southeastern Washington County .................... 12 Index map to geologic sections ................................. 13 General geologic sections ....................................... .............. 14 Geologic sections ..................................................................... 15 Geologic sections ....................................................................... 16 Alluvially filled terrace valley lying on the Alum Bluff group ........................................ --- ---------------------------- ---- 17 Alum Bluff sediments exposed at locality H-12, Holmes County ......................................................................... ................ 18 Contact of the deposits of the 170-220 Foot Surface with the Choctawhatchee formation, near Newhope, Washing- ton County .................. ..... ............... ............ ... ................. ... .. 19 Underground stream exposed in a small sink formed in the Choctawhatchee formation (locality W-14) in "The Deadens" prairie ........................................ ............... 20 Cross-bedded, highly carbonaceous sands underlying the 170-220 Foot Surface, at locality W-1, Washington County.. 7 10 11 17 19 20 22 23 29 31 31 36 37 38 39 81 86 104 107 136 FOREWORD The study of Holmes and Washington Counties is made possible by a cooperative agreement between the School of Geology of Louisi- ana State University and the State Geological Survey of Florida. The School of Geology provided laboratory facilities and offices; the Flor- ida Survey furnished financial assistance. Dr. Henry V. Howe, Director of the Louisiana State University School of Geology, directed the research, prepared the checklists on the Foraminifera, and accompanied the writer on several field trips in the area. Dr. James H. McGuirt, Assistant Professor of Paleon- tology, Louisiana State University, prepared the lists of Bryozoa and also accompanied the writer on several field trips. Mr. Robert Hendee Smith, Mr. Benjamin A. Tator, graduate stu- dents at Louisiana State University, and Mr. Charles Walton of Bir- mingham-Southern College, Birmingham, Alabama, assisted the writer in the field work. Appreciation is hereby accorded to various members of the Louisi- ana State University faculty, who gave freely of their time in criti- cism and discussion. The writer is grateful to Mr. R. L. Dowling, 1937-41 Supervisor, and Mr. S. E. Rice, the present Supervisor of the State of Florida Department of Conservation; and to Mr. Herman Gunter, State Geolo- gist, for their financial aid. Mr. Gunter made available his type fossil materials, publications, and equipment. Mr. Horton Buchan, cartographer for the Florida State Road Department, partially pre- pared the map base. Mr. Douglas Smith, student of engineering, Louisiana State University, prepared all other illustrations and maps accompanying this report. Mr. Harry Goodrich, Director of C. C. C. work, U. S. Department of Agriculture, furnished the U. S. Forest Service timber type maps to be used as a base for the geological maps accompanying the report. 'Dr. Julia Gardner, Paleontologist, and Dr. C. Wythe Cooke, Ge- ologist, United States Geological Survey, assisted with some of the field problems. The writer is also grateful to Dr. R. S. Poor, De- partment of Geology and Geography, Birmingham-Southern College for encouragement and inspiration. Citizens of each county were generous in assistance and interest. ABSTRACT This report on the geology of Holmes and Washington Counties, western Florida, describes the results of a detailed study of the counties. A brief summary of the resources, utilization of land, and classi- fication of each county is given. The early Indian occupation of this area is shown by the presence of a series of mounds. Artifacts collected from these suggest that the middens were constructed in the Weeden Island II period (1400-1550 A. D.). The area can be roughly divided into two physiographic provinces: (1) The River Valley Province, including four depositional stream surfaces and associated older rocks; (2) The Coastal Plains Province, including five coastwise surfaces and associated older rocks. It is believed that these stream surfaces were formed much the same as the present flood plain, but the origin of coastwise surfaces is not fully understood. There have been at least six stages of erosion followed by six stages of deposition during which the Pliocene? and Pleistocene surfaces were developed. The separation of these levels resulted from epeiro- genic uplift of land, or eustatic lowering of sea level. Reconnaissance of the counties by car was supplemented by foot and boat traverses, during which hundreds of samples were collected. These were studied in the laboratory, their lithologic and paleonto- logic compositions were described, and the formation represented by each identified. Twelve mappable units are shown on the appended geological maps (scale: 1 inch to 3520 feet). The oldest rock outcropping in these counties is of Eocene (Jackson group) age; the youngest is the Recent alluvium. The Marianna limestone (Oligocene) is mapped in Florida west of the Choctawhatchee River for the first time. The Suwannee limestone (Oligocene) is shown to be a distinct lithologic unit that varies in paleontologic content from locality to locality. As tentatively mapped in this area the Suwannee limestone is prob- ably equivalent to the Glendon limestone, Byram calcareous marl, and lower Chickasawhay formation of southern Alabama and eastern Mississippi. The Alum Bluff group of the Miocene is considered as a forma- tion (a mappable unit) in this report. Only the Chipola formation is present in eastern Washington County. Westward the Alum Bluff group thickens and wedge-shaped deposits contain distinct faunas which are separable into three units. Likewise, the Choctawhatchee Miocene faunal zones do not represent different time intervals, as previously considered. The Arca and Yoldia zones are shown to be time equivalents of the Ecphora and Cancellaria zones that differ only in faces. Gravel, sand, clay, limestone, and water are economically important, although these resources have not been exploited in these counties. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA b Robert 0. Vernon INTRODUCTION LOCATION Holmes and Washington Counties are in the central portion of western Florida. They are bounded by Walton County on the west, Bay County on the south, Jackson County on the east, and Geneva County, Alabama, on the north. Holmes County, northernmost of the two, was created January 10, 1848 from territory that previously had been a part of Walton and Washington Counties (Cash, 1938, p. 825). Its present boundaries, however, were not established until 1915 (Cutler, 1923, p. 577). At present it includes a land area of 506 square miles. Holmes Creek marks its eastern boundary. Washington County is bounded on the west by the Choctawhatchee River. It is one of the original twelve counties of Florida, and was set off from Escambia and Jackson Counties on December 29, 1824 (Williams, 1827). At one time Washington County included parts of Bay, Holmes, and Calhoun Counties. When Bay County was created in 1913, Wash- ington County was cut off from the Gulf Coast and lost fully one-half of its population (Cash, 1938, p. 826). Its present boundaries were established in 1915, when Holmes County was enlarged to the south of Bonifay by twenty-two square miles. The area of Washington County at present is 625 square miles. MAPS Excellent maps covering both Holmes and Washington Counties are published by the Forest Service of the United States Depart- ment of Agriculture. These maps have an excellently surveyed drain- age and land grid. All culture present up to the time of publication FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 is accurately portrayed and located. The latest Florida State Road Department maps were also helpful in preparing this report. Maps covering Holmes and Washington Counties used in this survey are listed below: U. S. Department of Agriculture, Forest Service: Holmes County Timber Type Map, 1937. U. S. Department of Agriculture, Forest Service: Washington County Timber Type Map, 1937. University of Florida Agriculture Extension Service: Holmes County Reconnaissance Soil Map, 1936. University of Florida Agricultural Extension Service: Washing- ton County Reconnaissance Soil Map, 1936. Department of the Interior, U. S. Geological Survey: DeFuniak Springs Quadrangle, Florida. Scale, 1:62,500; contour interval, 10 feet; 1935. Florida State Geological Survey and United States Geological Survey: Geological Map of Florida. Scale, 1:1,000,000; Flor- ida State Geological Survey, 20th Annual Report, 1929. Florida State Road Department: Holmes County Road Map, 1936. Florida State Road Department: Washington County Road Map, 1936. INDIAN OCCUPATION Pre-historic habitations in Holmes and Washington Counties are indicated by the presence of mounds, shell middens, arrow heads, and pottery. A small midden composed of fresh-water and marine shells is present in the SE1/4 SE1/4 sec. 2, T. 1 S., R. 17 W. A collec- tion of artifacts from two other mounds in Washington County was sent to Mr. Gordon D. Willey, Columbia University, for determination. Mr. Willey' states: "Although the following archaeological data are rather meager, they can be analyzed in terms of the typology and the chronological sequence which have been formulated upon the basis of previous investigations undertaken in northern Florida. The analysis by archaeological site follows: Site no. 1 Location A shell mound or midden six miles south of Caryville in Washington County (NW% NW% of sec. 33, T. 4 N., R. 15 W.). 'Letter to Mr. George Quimby, Supervisor of the W. P. A. archeological project in Louisi- ana, Baton Rouge, Louisiana. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 8 Pottery (Catalog no. 5416, L. S. U. Geology School) 1. Cord-marked, plain rim sherd. 1. Weeden Island type rim sherd. 1. Wakulla Check Stamped sherd with folded rim. 1. Indeterminate stamped sherd. 2. Sand tempered plain sherds. 6. sherds. Temporal Position "Although there are not many diagnostic sherds in this small collection the evidence suggests the period known as Weeden Island II. Cord-marked sherds are rare in West Florida, but appear to have been introduced during this period. An estimated date for Indian occupation manifested by these sherds would be 1400-1550 A. D. Site no. 2 Location A shell mound or midden northwest of the Crystal Lake Postoffice in Washington County (SE4 NE NW%1 of sec. 29, T. 2 N., R. 14 W.). Pottery (Catalog no. 5417, L. S. U. Geology School) 2. Carrabelle Punctated Rim sherds. 12. Wakulla Check Stamped sherds. Four sherds have small folded or rolled rims. Other sherds suggest small collared jars with partly flattened bases. 1. Weeden Island Incised sherd. 2. Incised and punctated sherds which are Weeden Island types but there are too little data to identify the specific type. 20. Sand tempered plain sherds. 6. Indeterminate stamped sherds. Three of these sherds have simple stamp impressions which are Weeden Island period in context or perhaps earlier. Two other sherds have rather unique rims. 43. sherds. Temporal Position "This collection probably belongs to the Weeden Island II and the esti- mated date of this period is 1400-1550 A. D. "Summary: Both collections suggest that the middens were constructed in the Weeden Island II period. 1400-1550 A. D., although it must 6e remembered that the archaeological evidence consists of surface collec- tions. Possibly complete excavation of these sites would show earlier styles of artifacts. It seems likely, however, that the occupation would not he earlier than Weeden Island I. estimated date, 1200-1400 A. D. and the Weeden Island II period, 1400-1550 A. D. is more probable." UTILIZATION OF RESOURCES AND PRESENT CLASSIFICATION Holmes County includes 323,820 acres, of which 65,300 acres are cultivated fields. Washington County utilizes 43,990 of its 400,032 acres in farms.2 The population of both Holmes and Washington *United States Department of Agriculture, Forest Service, Maps for Holmes and Wash- ington Counties, 1937. 4 FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Counties is rural. In 1935 Holmes County was populated by 14,449 people, of whom 704 were Negroes, and Washington County was pop- ulated by 12,899 people, of whom 2,898 were Negroes.3 The popula- tion of Holmes County increased to 15,447, and that of Washington County decreased to 12,302 people in 1940.4 The U. S. Census of Agriculture for 1935 values the farms of Holmes County at $2,311,018; those of Washington County at $1,302,004. The income of these counties largely comes from:5 Sw ine (heads) ................................................................. Cattle (heads) ................................................................. Goats (heads) ................................................................. Sheep (heads) ................................................................. Chickens ............................................................. ............. Corn (bushels) ...................................................................... Sw eet Potatoes (bushels) ........................................... Sugar Cane (tons) ......................................................... Cotton (bales) ................................................................. Tobacco (pounds) ............................................................ Irish Potatoes (bushels) ............................................. Holmes 15.400 11,762 1,825 3.488 45.971 309,652 80,949 6,033 4,507 8,769 7,708 Washington 10.166 11,598 2,578 4,231 33.066 170.306 43.943 6.645 1.084 1,924 2,912 During the years 1936 and 1937 the main farm products were : Holmes Peanuts (bushels) .............................................................. 60.020 Corn (bushels) ................................................. ......... 253,620 Cotton (bales) .................................................................... 6.268 Velvet Beans (bushels) ................................................. 127,466 Sugar Cane Syrup (gals.) .............................................. 88,930 Sweet Potatoes (bushels) ................................................ 45,808 The U. S. Forest Service indicated on its Timber 1937 the following utilization of land area: Holmes Cultivated fields ................................................................ 65,300 Towns, Railroads, etc. ................................... 10,650 Pine, cypress or gum timbers ........................................ 167,756 Hardwood timber ................................................................ 80,090 Non-tim bered ......................................................................... 24 323,820 acres Washington 83,034 160,327 1,213 63.834 15,006 Type Maps of Washington 43,990 15,094 251,056 89,8(19 23 400,032 a. Principal industries, other than farming, in these counties, are timbering and the manufacturing of naval stores. *Florida State Census for 1935. 'Sixteenth Census of the United States, 1940. 'United States Census of Agriculture for 1935, Part 1, pp. 546-553, Part 2, pp. 562-564. *Florida Agricultural Statistical Report, 1936-1937, Fla. Dept. Agr., 1938, pp. 93, 94, 195. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES. FLORIDA 5 PHYSIOGRAPHY INTRODUCTION The physiography of Holmes and Washington Counties may be divided roughly into two units: 1) River Valley Province, including part of Cooke's (1939) Marianna Lowlands, or the Florida Geological Survey's Marianna-Chipley Lowlands; 2) Coastal Plains Province, including parts of Cooke's (1939) Western Highlands and Coastal Lowlands Provinces. The River Valley Province includes the flood plains of the Choc- tawhatehee River and its tributaries; four depositional alluvial ter- races, similar in origin to the present flood plains, and related to the present drainage; and Tertiary sediments, exposed along stream channels and escarpments separating terrace levels. The Coastal Plains Province consists chiefly of five surfaces or plains lying approximately parallel to the present coast. Four of these plains are bounded by erosional escarpments and hence may be considered terraces. A higher plain, lying at elevations between 250 and 320 feet, has no known bounding scarp landward, and differs from the lower plains in areal extent and lithology. Its deposits are highly oxidized, cross-bedded, coarse to fine grained alluvial deposits, and spread over western Florida in a delta-shaped mass. The deposits underlying the lower surfaces are light colored, fine-grained elastics, only rarely cross-bedded. Tertiary sediments outcrop along deep valleys cut through the deposits underlying the five surface,-, and along the escarpments sep- arating them. Terrace deposits rather than terrace surfaces have been mapped on the appended geological maps (plates I and II). The relationships of the terrace deposits and surfaces to older rocks, and to each other, are shown in geologic sections represented by figures 14 and 15. RIVER VALLEY PROVINCE The River Valley Province covers all but the western part of Hohnes County and the southern part of Washington County. It lies along the main drainage system of the Choctawhatchee River and its tributaries. Sediments of this province consist of Recent and ter- race alluvium and Tertiary deposits. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 The Coastal Plains Province originally extended over this area and connected with the same province in central Washington County and western Holmes County. Remnants such as Rock Hill, Falling Water Hill, Orange Hill, High Hill, and Oak Hill are preserved south of Chipley, Washington County. Erosion, combined with solution activity in sinks and swamps, has reduced this h:gh land area to elevations lower than the land to the south, producing a steep north- facing -carp which separates the River Valley Province from the higher sand hills of the Coastal Plains Province. This escarpment is known locally as the "Holmes Valley Escarpment". For convenience of discussion, the River Valley Province is divided into the Choctawhatchee River, its principal tributaries, and the terraces along these streams. Choctawhatchee River The Choctawhatchee River bisects Holmes County and marks the western boundary of Washington County. It is a vigorous, slightly meandering stream, with a gradient of approximately 1.4 feet per mile in its lower portion. This gradient increases headward to ap- proximately 2.5 feet per mile near Geneva, Alabama. Along the channel silicified limestone of Tertiary age forms rapids. The flood- plain deposits are approximately thirty feet thick in the southern extensions, but headward, in the vicinity of the Alabama line, they are only thin veneers over nearly continuous outcrops of Tertiary limestone. Flood plain. The flood plain of the Choctawhatchee River con- sists of alluvium deposited in a shallow valley formed during an earlier period of downeutting. The Choctawhatchee heads in northern Alabama and is at all times heavily loaded with sediment. This sediment is deposited in the relatively still water of Choctawhatchee Bay, forming a delta. The formation of the delta decreases the gradient of the river in its lower portion and extends the alluviation upstream. Tributaries to the Choctawhatchee River head within the River Valley Province. They are spring fed, and flow for the larger part of their courses across limestones. These streams, therefore, carry comparatively little sediment and fill their valleys much more slowly than does the Choctawhatchee River. The more rapid alluviation of the Choctawhatchee thus dams Pinelog, Holmes, Wrights, and Sandy GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 7 Creeks where they enter the main valley and forms lakes in the lower part of each tributary valley. These lakes along tributaries were first noted by Sellards (1916, p. 109) in connection with the Apalachicola and Chipola Rivers. Later he (1918a, pp. 86-87) observed similar features on Pinelog Creek, a tributary to the Choctawhatchee River. Sellards states: "The valley of the Apalachicola river is being rapidly aggraded by reason of the load of sediment carried by that stream; the valley of the Chipola, on the other hand, is being built upl, much more slowly. The result has been a blocking of the Chipola at its entrance into the Apalachicola by sediment carried by the main stream, thus forming the b(;dy of water known as the 'Dead Lakes' in Calhoun County. Pine Log creek, a tribu- tary entering the Choctawhatchee from the east is blocked in the same way, forming a lake several square miles in area." This alluviation began so recently that swamp vegetation of the tributaries is still standing, though dying or dead (fig. 1). Sound- ings made in the tributaries prove that their lower ends are 5 to 10 feet deeper than the Choetawhatchee River. They are flowing es- Figure 1. Drowning of the lower part of Holmes Valley, in sec. 29, T. 2 N., R. 16 W., developed as a result of the dannming of Holmes Creek by high flood- plain deposits along the Choctawhatchee River. Photo by Dr. Julia Gardner. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 sentially on the old cut valley floor, whereas the Choctawhatchee River is flowing on alluvium deposited in its cut valley. The Choctawhatchee flood plain has been built as much as 15 feet higher than the flood plains of its tributaries at the same latitude. As a result, the tributaries flow-parallel to the Choctawhatchee River for several miles before gaining entrance. Distributaries, such as East River, have broken through the natural levees of the Choctaw- hatchee and have entered the parallel streams which reenter the Choc- tawhatchee as tributaries lower in its course (see figure 7). Natural levees. Natural levees, the dominant land feature on flood plains, are only meagerly developed along the Choctawhatchee River. In flood, the stream tops the channel banks in many places, spreads out over the flood plain and deposits a thin veneer of sediment. The coarsest sediment and largest proportion per unit area is dropped immediately adjacent to the channel banks. With distance from the main channel, deposition proceeds more slowly as the sediments car- ried become finer. This results in a slight slope away from the river channel, and a steep slope toward the stream. The height of a natural levee is "a measure of the stage difference between high and low water" (Russell, 1939, p. 1210), and its width is con- trolled by its age and the size of the channel. As streams alter their courses, new levees are formed in the new position. Old channels may thus be distinguished from new chan- nels. Ox-bow lakes represent a meander on a former stream course, the open ends of which were cut off from the new channel by levee deposition. Many of these ox-bow lakes occur on the lower reaches of the Choctawhatchee River. Rim swamp streams, (Russell, 1938, p. 73). Natural levee back- slopes concentrate waters of flood plains toward the bases of mar- ginal valley walls. These valley side lowlands are called rim swamps, and streams running parallel to the bounding scarps are known as rim swamp streams. When flood plains become terraces, aggradational patterns are destroyed only slowly. Levees and rim swamp streams are still pre- served on the lower terraces along the major streams. Excellent examples may be seen on the lower terraces along the east side of the Choctawhatchee River in central Holmes County. Higher ter- races are so eroded that such patterns cannot be distinguished. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 9 Tributaries to the Choctawhatchee River Major tributaries of the Choctawhatchee River are Holmes, Wrights, Sandy and Pinelog Creeks. The valleys of these streams have been formed chiefly by solution of limestone beds. As has been noted, the tributaries are largely spring fed and therefore carry comparatively little sediment except during periods of heavy rain- fall, when surface drainage assumes the dominant role. Numerous outcrops of Tertiary sediments occur in the channels of the streams, but the banks are composed of thin veneers of alluvium overlying Tertiary sediments. Flats occur on either side of the channel but they are extremely narrow and swamp vegetation may grow down to the stream banks. The only expression of natural levee alluviation is the presence of small sand ridges along the channel banks, with the densest swamp in the position of any normal rim swamp. Seep- age in swamp areas often creates streamlets which hug the base of the valley wall in the manner of a rim swamp stream. The flood plains of these tributary streams are being partially built by the Choctawhatchee River, which floods into their mouths and builds deposits that extend into the tributaries. The lakes formed in the lower portion of each tributary valley by the greater alluvi- ation of the Choctawhatchee River are also receiving deposits. De- posits at the upstream ends of the lakes are built by the tributaries, while those in their lower ends are formed by the Choctawhatchee. The tributary streams meander sharply through these lakes, with frequent cutoffs along their channels. Many of these cutoffs are due to vegetation dams. Stream Terraces Patches of alluvial material, well above the flood plains, lie along the sides of all the major streams in Holmes and Washington Coun- ties. These sediments occur at four7 definite levels, each bounded by stream cut scarps (see fig. 2). Each of these levels represents a period of alluvial drowning of river valleys following a period of valley cutting. By connecting these patches of alluvium along a projected slope the longitudinal profile of the former river can be restored. Res- toration of these four levels indicates that each has a definite ele- vation above the flood plain, and, if original surface irregularities 'In addition to these four definite levels there is present in this area a fifth and highest alluvial plain which apparently is unrelated to the present drainage. This surface is believed to be a coastwise delta-plain and will be discussed under "Coastwise Surfaces." FLORIDA GEOLOGICAL SURVEY-BULLETIN" 21 Fig. 2. The escarpment in the background separates the 30-50 Foot Surface from the older 60-100 Foot Surface in sec. 14, T. 6 N., R. 16 W., Holmes County. and subsequent dissection are disregarded, all of the levels are ap- proximately parallel and slope approximately 1.3 feet per mile. These four terraces occur at 10-20 feet, 30-50 feet, 60-100 feet, and 145- 165 feet above the present flood plain. These valley terraces are remnants of formerly continuous flood plains which were wider than those of the more recent valleys cut in them during subsequent periods of downcutting. However, where the former valley was only a little wider than the present valley, erosion of the latter has largely destroyed the pre-existing flood plain. These scattered remnants along the valley are correlated and pro- jected into a reconstructed profile in fig. 3. The geological maps (plates I and II) show that in Holmes and Washington Counties matched levels occur facing each other across the present valley floor. The older higher terraces are wider than the younger ones, indicating a progressive decrease in valley widths along any given valley cross-section. This may be partially explained by the progressive extension of stream bare levels. In other words, if the factors controlling stream base levels occur progressively down gradient, and if every stream flood plain narrows headward, then each stream terrace would be narrower than older ones along any valley cross-section. These decreasing widths also may be explained by a progressive change from overloaded, braided streams to present- day meandering streams (Russell, 1939, pp. 1199-1202). Wider ter- GEOLOGY OF HOLMES -AND WASHINGTON COUNTIES, FLORIDA 11 Figure 3. Generalized and diagrammatic profile across the Choctawhatchee River in central Holmes County. races on older deposits thus do not necessarily indicate streams larger than those which ex:st in the region at present. The ancient streams flowed in shallow, wide valleys, whereas present streams flow in deep, narrow valleys, cut into and through older alluvium. These four terraces are separated by their relative heights above the Recent flood plain, by escarpments separating each level from older and younger surfaces, by the amount of erosion of the various levels, by the stage of drainage development, and by the degree of preservation of old alluvial patterns. The amount of oxidation and compaction, and the presence of small slump structures, also may be used to separate the oldest from the youngest deposits (see table 1). Though the relationships between the higher stream surfaces and the higher coastwise surfaces can not be determined in this area, the lowest fluvial surface (10-20 Foot) can be traced onto the lowest coastwise surface (5-30 Foot). At the point of junction, the fluvial surface lies at a slightly lower elevation. This relationship can be seen in the vicinity of Bruce, Walton County. The flood plain of the Choctawhatchee River ends in a delta at the head of Choctawhatchee Bay. The U. S. Coast and Geodetic Survey's hydrographic charts (1922) of this area show the deepest part of the bay to be immediately seaward from this delta, and a channel can be traced through the bay some distance out into the Gulf. The Gulf bottom when contoured on these charts shows a physiography similar to the lower coastwise surfaces, with flat bot- toms extending out at least 8 nautical miles. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 U 0; oC v2 , 0) P-P 02) Q, 0' -P -o -z 01 0) t -4- ci a 0 -a -P W ci ci a ci o-. F-' 0) aU O-P 14 6'* a) C.) W rn 0 -o a) 5. a a) C-. h 04 '- 0 0 04 a I ft '-4 a) ci 04 c3i OS 01 a)s '01 0 0 o 8 04, a cd Ca cd 05 F C a) '0 a) CL ci a) OS ci 0- -P 01 cci 013 cdg a) C) *-i 1-1 OSa) ci% .rt Q .- a h r-4 0 0 a) OS a'd U) a) ci 3 n a) '0 04 ci 0 -d ci Os a) C.) 01 c'0a Uoa 01 V (a a PI 1i: a CD a ci OS Q> *I 43 -d 0i 3 04 c i cSi cS 0 - a) 0 4- 00 o -0 -4I 0 I -P a) H0 C3 c0 a 1-c -P 0 b0 U) CI) (f, 0) 4Z a 42 '0 c 3i 4-P U-' 0 0'2 0 u *a tP 0) a0 ca 1P O~c 010 -6 d 0) 0 C 4^=1 cici 0, a) .-4 bo CSO PS| -P -3 a) Sa I. 0 Crs GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 13 The writer, therefore, believes that the fluvial terraces ended in former bay-extensions, much the same as the flood plains end in bays along the present coast. The fluvial surfaces would thus be related to coastwise surfaces as the present flood plains are related to the present shore line. 10-20 Foot Surface. This surface is the lowest level above the present flood plain of the Choctawhatchee River. During extremely high stages of the river (one in approximately 20 years) this level is flooded,8 though scarps 10 to 15 feet high separate it from the floodplain flats. This surface merges downstream with a similar sur- face on Holmes and Pinelog Creeks. Except for the lower ends, which were flooded by the Choctawhatchee River during abnormal floods in 1909 and 1928, the flats on the creeks have never been covered by high water during historic times. Similar scattered and unrelated surfaces in Louisiana have been mapped as high-level flood plains and assigned to the Recent Period. These features in Louisiana have been considered to be cut surfaces formed during valley widen- ing (Fisk, 1938, p. 54).. Russell (1940, p. 1220) also regarded these secondary terraces as having: "-resulted from the swinging of a stream from one side of its valley to the other during entrenchment. Terraces also result from changes in gradient caused by shifts in distance to the point of debouchement.' West- ward flowing streams in the state of Mississippi typically had flood plains adjusted to the Teche-Mississippi course. Such streams were shortened when the Mississippi adopted its present channel and increased gradients have permitted entrenchment, resulting in an excellent system of modern terraces. Benches are also produced along valley sides as the result of lateral corrasion and these become terraces after rejuvenation has become effective." In these Florida counties, however, this level is definitely trace- able from the Gulf of Mexico into Alabama. It occurs on both sides of the valley and is separated by low escarpments from the flood plain. Any explanation of higher terrace levels must be applied to this surface as similar conditions characterize both. The surface is well preserved as discontinuous narrow bands on both sides of the Choctawhatchee River, and small alluviation fea- tures are quite evident. In central Holmes County a remnant 3.5 miles wide is preserved. Sikes Creek is an accentuated rim swamp stream marking the former position of the old rim swamp. It has little cutting power and drains the surface between the river and "According to the farmers of the vicinity, the abnormally high waters of 1909 and 1928 resulted from breaks in the dam at Elba, Alabama, and from insufficient outlets beneath the railroad and highway at Caryville, Florida. *Reported earlier by Fisk (1938a, p. 15). FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 the creek. Poorly defined natural levees are evident. The former flood plain extends up tributary stream systems in a typical "allu- viated pattern", with the height of the bounding escarpments de- creasing headward. In southeastern Washington County all fluvial terraces except the 10-20 Foot Surface have been removed by erosion. In this area the Choctawhatchee River has apparently occupied the same narrow val- ley throughout each period of cutting and each period of filling. Headward there periods of cutting and filling are separable, but along this narrow portion only the latest is evident. The last period of valley cutting was apparently of shorter duration than those pre- ceding it and the 10-20 Foot Surface remains. 30-50 Foot Surface. This slightly dissected surface is developed chiefly in Holmes County. It has a width of two and one-half miles at the Alabama line, and widens downstream. In the vicinity of Caryville, the original surface exceeded 7 miles in width. Throughout th:s distance it occurs as patches on both sides of the river. Natural levees are well developed and preserved on the remnant east of the river in central Holmes County. The surface is poorly drained and so slightly dissected that rim swamp features are Etill evident. Al- luvial drowning is shown by the extension of the surface into tribu- tary valleys. Wr'ghts and Holmes Creeks, and Pea River seem to have been the chief tributaries to the Choctawhatchee River in this area during the time of development of this old flood plain. An extremely flat section of this surface, developed along Pea River, extends into the northwesternmost part of Holmes County. 60-100 Foot Surface. This surface is badly dissected, and the original flat surface is preserved only in the vicinity of Geneva, Alabama, and in the wect portion of T. 6 N., R. 15 W. In. many places the intermediate surfaces are absent, and the present flood plain lies immediately below this level. In such cases, Tertiary outcrops are common at the base of the scarp. A small outlier of a higher terrace, partly surrounded by silicified Tertiary boulders, is well preserved in the midst of this terrace in sees. 19 and 30, T. 6 N., R. 15 W. The 60-100 Foot Surface on Wrights Creek is represented only by scattered remnants. Holmes and Ten Mile Creeks, however, are flanked -by wide remnants of this: surface, and appear to have been major tributaries to the Choetawhatchee River during this time. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 15 Along the Choctawhatchee River, this surface is developed, near the Alabama line on the west side of the River. From there the surface abruptly turns east in central Holmes County and extends up Ten Mile and Wrights Creeks. Downstream the junction of this surface with that developed along Holmes Creek covers most of north- western Washington County. 145-165 Foot Surface. This surface shows the best development of drainage, and is the most dissected of any of the stream terraces. The flat topped h:lls of northeast Holmes County reach elevations near those of the original surface. The best preservation of this surface is southeast of Geneva, Alabama, near the Alabama-Florida line, where the flats are utilized as farms. Pea River, and perhaps Holmes Creek, were the chief tributaries to the Choctawhatchee River during this period. Pea River prob- ably emptied into the Choctawhatchee River in the vicinity of Esto, Holmes County. Alluvial deposits of this old Pea River course are preserved in northern Holmes County. If Holmes Creek was active during this time, it probably joined the Choctawhatchee River well north of Bonifay. In general, the surface has been reduced much below its original plain and younger valley development has cut out all of it south of Pates Lake in northwest Wash:ngton County. Tertiary sediments, some of which are silicified, are exposed along the deeper valleys, cut into this terrace deposit. COASTAL PLAINS PROVINCE The Coastal Plains Province extends inland from the present shore in Bay County and occupies southern Washington and southwestern Iolmes Counties. It partly encloses the River Valley Province, and probably extended at one time over most of this area, as remnants are present in northern Washington and western Holmes Counties. The Province includes five coastwise surfaces. The two upper sur- faces are known locally as the "sand hills" and the lower ones as the "pine lowlands". COASTWISE SURFACES Introduction. Unfossiliferous sand, gravel, and clay deposits of late Tertiary or Pleistocene age blanket the outcrops of marine Ter- tiary throughout most of Holmes and Washington Counties. In south-.. ern Washington,. Bay, and western Holmes Counties, these deposits FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 occur associated with five definite levels. These surfaces could be old ocean bottoms, as they are marked landward by seaward-facing scarps and reentrant alluvial valleys. Likewise, ridges similar to the present beach ridges occur immediately landward of the escarpments, and the surfaces occupy narrow bands running approximately parallel to the present coast. Hydrographic charts of western Florida, pre- pared by the United States Coast and Geodetic Survey in 1922, indicate that the physiography of the present Gulf bottom does not differ materially from that of these coastwise plains. Similar terrace surfaces occur elsewhere on the Gulf and At- lantic coastal plains. In Louisiana, four terraces are reported by Fisk (1938, p. 56), but these are thought to be stream terraces with coastwise delta plain extensions. Distinct levels are also developed in Florida along streams, but in west Florida they occur north of the area occupied by the coastwise surfaces. The projected slopes of these fluvial surfaces in Holmes and Washington Counties lie at -'lightly lower elevations where they join the coastwise surfaces so it is uncertain whether the stream surfaces were formed contempo- raneously with the coastwise surfaces, or are of different age. Cooke (1939, p. 34) recognized at least 7 levels along the Atlantic and Gulf Coasts, which he assigned to a marine origin with delta extensions up streams. Matson (1913, p. 31) recognized 3 marine plains in Florida. He later agreed with Shaw (1918, p. 155) in rec- ognizing 4 Pliocene stream terraces and 4 "Quaternary plains or sea terraces". Shaw (1918, p. 132) assigned the Pliocene terrace de- posits to the Citronelle formation, but Cooke (1929, p. 181) recognized a Pliocene Citronelle upland which was terraced during Pleistocene time. Fisk (1938a, p. 14) recognized only Pleistocene terraces and considered his two highest terraces as possibly equivalent to the type Citronelle. To apply the various names used by these authors to so local an area as Holmes and Washington Counties appears unwise without tracing these levels outside the borders of Florida. In this report, therefore, the various levels are described, from youngest to oldest, without using names applied elsewhere. The surfaces of this area may be separated and discussed according to their elevations from the top of one scarp to the base of the next landward scarp (see fig. 4). This surface slope includes and projects along preserved remnants of the coastwise surface. It should be understood that such a designation is highly elastic and cannot be applied too rigidly. The lower value of any of these levels depends upon the amount of 16 , GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 17 120 120 60 60 31(1 3 Note:Horizontal Scale Is Oiogrammalic I I Figure 4. Partial restoration of the 60-105 Foot Surface, separated from younger and older surfaces by seaward facing escarpments. erosion the. surface has undergone in the formation of the lower es- carpment, and varies as the original surface slope varied. On this basis, 5 definite levels have been recognized in Bay, Holmes, and Washington Counties: 1) 5-30 Foot, 2) 60-105 Foot, 3) 115-150 Foot, 4) 170-220 Foot, and 5) 250-320 Foot. Dr. C. Wythe Cooke of the United States Geological Survey spent two weeks in the field with the writer and correlated his Pamlico terrace with the 5-30 Foot Surface, his Wicomico with the 60-105 Foot Surface, his Sunderland with the 115-150 Foot Surface, his Coharie with the 170- 220 Foot Surface, and his Brandywine with the 250-320 Foot Surface. Dr. H. N. Fisk, Louisiana State University10 tentatively correlated his Prairie terrace with the fluvial 30-40 Foot Surface, his Mont- gomery with the fluvial 60-100 Foot Surface, his Bentley with the fluvial 145-165 Foot Surface, and his Williana with the coastwise 250-320 Foot Surface. The correlation of the terraces as indicated by Cooke and Fisk is tabulated on the following chart. Matson's three levels, and four terraces in Georgia described by Cooke (1925) are ako given, but Shaw's terraces are somewhat confusing and the writer hesitates to venture a correlation. "1Personal communication, December, 1940. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 cd ho c 4 0 0 d -_ __ o PPC t o o o o rI u Q u In a) 41 w D O | |k 9 S2 t-z C3 ) m c) a) W ca r w +_') ;> z W + : U w4S 0C) Uiz) .4- ( g a & 643) Ca) 2.. 0 o3 0 0i cd 0 0 d 0 0 0 0 P do (O -0 dO IO d d Soo oo o oo o oo o 0 0 o o 0 ____ ------------------ __--- i 2 - -c C C C C O O C)li I 0 0N -. 5 3 0 cad 0 4a ,.Z -C cC 02 03 0 0'ts r P1 a) I I a 0 cU o o C C 0 0 0 F' *' o a o0) J. < ^ 6 -; wE _ . GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 19 The 5-30 Foot Surface. This surface is well developed in south- ern Bay County, but does not extend into Holmes or Washington Counties. A discussion of it is included in this; report to aid the interpretation of older more dissected surfaces. The 5-30 Foot Surface is probably contemporaneous w:th the fluvial surface that lies 10-20 feet above the present flood plain. This is not evident in Holmes and Washington Counties, but the two surfaces are in contact along State Road 10 in the vicinity of Bruce, Walton County. At the po'nt of juncture, the fluvial surface lies at a slightly lower elevation. The 5-30 Foot Surface is separated from older levels by a 15 to 30 foot escarpment. The present coast is definitely a coast line of submergence, as evidenced by the many drowned valleys and bays. This indicates a rising sea level, re ulting in a wave-cut cliff along most of the ex- posed coast. This process is especially evident at Pensacola, Florida. Combined with this wave-cutting action, high storm waves are bu'ld- ing a beach ridge along the coast (see figs. 5 and 6). Wind action moves this sand ridge gradually inland. This results in a Recent wave and wind deposit overlying the coastward edge of the 5-30 Foot Surface. Bore holes in the dune area at Panama City penetrate 10 to 20 feet of dune sand before passing into black soil, at an ele- vation of about five feet. This soll is apparently developed upon the lower portion of the 5-30 Foot Surface. The highest elevations ... .......-...... .. Figure. 5. Recent beach ridge and dunes formed on the 5-30 Foot Surface near the'Panama City, Bay County, bathing beach. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Figure 6. Diagrammatic profile of beach ridge and sand dune accumulation on the 5-30 Foot Surface. on the old plain occur along this sand ridge immediately adjacent to the coast; reaching elevations as high as 50 feet. This ridge is mapped with the 5-30 Foot Surface and similar ridges on older sur- faces are mapped with the surfaces on which they obcur. This plain, the lowest of the coastwise surfaces, extends as much as 16 miles inland, and the landward margin is marked by a smooth, cu-pate, seaward-facing escarpment. The width, however, is highly variable. The altitude is also variable, with local elevations as high as 50 feet and as low as 10 feet. The lower places are occupied by swamp and marsh vegetation, with abundant saw palmetto. Drainage patterns on the 5-30 Foot Surface have been largely determined by the presence of the beach ridge. When the 5-30 Foot Surface was first exposed consequent drainage took advantage of irregularities and ran the shortest possible distance to the Gulf. This resulted in most of the streams running almost at right angles to the coast line. Rising sea level caused wave-cut cliffs and beach ridges to develop and move inland. The!e ridges, aided by any natural low areas, forced the streams to run parallel to the coast and to seek entrance to the Gulf at places where they were able to break through the beach ridge. The parallel streams became larger as more of the perpendicular streams became tributaries, and as more water was con- centrated landward by the developing beach ridge. The lower por- tions of the major streams thus soon developed parallel to the coast. Continued rike in sea level resulted in the drowning of these stream valleys and created the present bays that also lie approxi- GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 21 mately parallel to the coast. Good examples are furnished by the bays in the vicinity of Panama City. Some of these "parallel" bays lie at the base of the scarp separating the 5-30 Foot Surface from higher levels; others lie between the scarp and the Recent sand dunes. In the latter case small drowned valleys extend up to and slightly beyond the terrace escarpment. On all the coastal and stream terraces, the branchwork of small streams is restricted largely to a single terrace, except where sink development has captured or pre-empted surface drainage. Russell (1939, pp. 1222, 1224) observed that "in general it is everywhere true that few channels cross from one terrace to the next in propor- tion to the number of channels present on each surface concerned." This is not only true of the lowest surface but can be seen on the higher ones as well, where evidence of the drainage patterns and beach ridges is furnished by the location of sinks and by drainage still existing parallel to escarpments and ridges of coastwise surfaces (see fig. 7). The 60-105 Foot Surface. This surface begins at the top of the scarp rising above the 5-30 Foot Surface and extends inland to the base of the next scarp. It consists of a well preserved level, approx- imately 8 miles wide, that extends across Bay and southern Wash- ington Counties. Pinelog Creek is the remnant of an old stream formed during 5-30 Foot Surface time which has maintained its original course approximately parallel to, and north of, the land- ward escarpment of the 5-30 Foot Surface. Most of the Pinelog Creek tributaries are confined to the 60-105 Foot Surface and extend in- land to the base of the scarp separating the 60-105 Foot Surface from the next older level. However, Pinelog Creek crosses this scarp onto the next older level and divides into Bear Bay and Sweet Water Creeks, which run parallel to the scarp that has just been crossed (see fig. 7). The 20 to 30 foot scarp (see fig. 8) marking the boundary be- tween the 115-150 Foot and the 60-105 Foot Surfaces enters Wash- ington County approximately at the center of its southern boundary and extends in a cuspate pattern slightly north of east to Red Head, where it is interrupted by lower floodplain and stream terrace sur- faces. The surface varies in elevation from 50 to 105 feet above sea level. Elevations slightly higher than the inland flats are found near the lower scarp in Bay County, along a ridge similar to the beach ridge on the present shore (see fig. 7). Saw palmetto and long leaf pine are the common plants on this surface, though scrub FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 c'-- I. .* I M Q ~ 0 0i C-0 ov4 IIa 000 bi S .r i~ 5-- 0 ( ~ rb \34-3 \ r~l:C I * d / El k t-. ,"l J7 ; O'q o ,S f rr EF ~0 d o ' 1C O fAir0) ~./1. -p %8 iM' GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 23 Figure 8. Escarpment separating the coastwise 60-105 Foot Surface from the 115-150 Foot Surface, looking northeast across Blue Pond, southern Washington County. The arrow points to the escarpment. oak is dominant where the surface is well drained and cypress swamps are present in some low areas. This surface has been mapped with the fhivial 30-50 Foot Surface, although they are questionably contemporaneous. The 115-150 Foot Surface. This level makes up a band 5 to 7 miles wide, extending across southern Washington County. In this area the 115-150 Foot Surface is separated from the 170-220 Foot Surface by escarpments only in western Washington County. In east- ern Washington County recent drainage developed along the base of the scarp has exposed Tertiary between the two levels and the terrace outcrops are separated by a variable width of Tertiary sedi- ment. Exposures and wells indicate that the thinnest deposit of ter- race sediment is found at the base of escarpments. This line along the base of the escarpment represents the place where run-off most successfully develops. Away from this scarp thick sand and gravel deposits absorb water fast enough to prevent excessive run-off. How- ever, the thin veneer near the base of the scarp is easily removed and the Tertiary clays, limestone, and marls control the immediate surface drainage. Bear Bay and Sweet Water Creeks are entirely confined to this surface. Their tributaries rise at the base of the escarpment sep- arating the 115-150 Foot Surface from the 170-220 Foot Surface and run directly south. The creeks run approximately parallel to the FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 bounding terrace scarps, join to form Pinelog Creek, which crosses over onto the lower 60-105 Foot Surface (see fig. 7). Limestone sinks are well developed on this level and the surface is somewhat dissected by streams, so that it is not preserved in as much detail as the younger surfaces. The original slope, however, is relatively intact in the vicinity of the Crystal Lake Postoffice (see frontispiece). At Crystal Lake Sink remnants of a ridge (see fig. 7), similar to a beach ridge in location and lithology, reach an elevation of 20 feet above the inland flats. The 60-100 Foot Surface along streams is thought to have been formed at the same time as this surface, and they are therefore mapped together. The 170-220 Foot Surface. Because of the dissection of this surface and the lack of topographic maps, the boundaries of the surface can- not be determined precisely. Relatively uneroded remnants of the original surface still exist in the vicinity of New Hope Church, in sec. 24, T. 2 N., R. 16 W.; Ebenezar Church Village in the center of T. 2 N., R. 15 W.; and in the vicinity of Porter Pond and east into Jackson County. Its greatest width in Washington County is about 5 miles. Most sinks and streams developed on this surface extend below the contact between the terrace deposits and the Tertiary, so that outcrops of Tertiary are common. The surface has been partially eroded by' Holmes Creek, and all of the higher surface (250-320) has been cut out in western Washington County. The altitude of the original surface ranged from approximately 170 feet at the coastward margin to 220 feet at the landward margin. Where this original surface is not dissected it is as flat as the lower terrace surfaces, and slopes approximately 1.5 feet per mile. Two small ridges in the southern part of T. 2 N., R. 15 W., just north of the scarp separating the 170-220 Foot Surface from the 115-150 Foot Surface, are similar to the present beach ridges in both physiography and lithology. Alluvial deposits underlying the 145-165 Foot Surface are corre- lated with the deposits of this surface. The two surfaces probably were formed contemporaneously. The 250-320 Foot Surface. This surface has maintained its origi- nal plain remarkably well. Although greatly dissected, many wide divides still have relatively flat surfaces. Projected levels of the next lower surface indicate that a scarp of at least 30 feet, and GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 25 probably more, separated these two plains. In these counties no escarpment is known between the 250-320 Foot Surface and older deposits. The surface ranges from 250 feet at the top of the scarp separating it from the 170-220 Foot Surface, to 310 feet in outliers south of Chipley (Oak, Falling Water, Rock, Orange, and High Hills), and in western Holmes County. The same surface rises from 250 feet at DeFuniak Springs to 320 feet in northern Walton County and continues into western Holmes County. Lime sinks developed on the surface are now preserved only on a few of the divides, most of them having been captured by Recent drainage. All original drainage and surface alluviation patterns have been erased from this surface in Holmes and Washington Counties. Lith- ology of the deposits, however, indicates that this highest surface is, at least in part, an old deltaic plain. The deposits are very sandy and contain numerous lenses of gravel. High stream terraces, com- parable in stratigraphic position, are developed along the larger streams of southern Alabama, so that this plain could be the deltaic extension of those stream terraces. SUMMARY OF TERRACES The five coastwise levels recognized in Holmes and Washington Counties are developed on elastic deposits and are separated by definite seaward-facing escarpments. Each surface extends approxi- mately parallel to the present coastline. -The four alluvial terraces extending up the major streams were probably developed contempo- raneously with the four lower coastwise terraces. Alluviation patterns such as natural levees, rim swamp streams, and associated drainage are developed on the stream surfaces, and features similar to beach ridges, bays and associated drainage are developed on the lower coastwise surfaces and were probably present on all except the highest. Actual bay or swamp sediment has been found in the deposits of three of the coastwise surfaces. Deposits underlying the highest coastwise surface (250-320 Foot) differ in areal extent, in the amount of oxidation and slumping, and in lithological make-up from the deposits of all of the lower coast- wise surfaces, and probably represent a former delta plain. Bore holes and water wells drilled into terrace deposits show that both stream and coastwise surfaces are underlain by elastic deposits limited beneath that surface. Each deposit grades downward FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 into coarser grades, and the base of each deposit is lower than the base of preceding terrace deposits, indicating that a period of cut- ting preceded each period of deposition. The escarpments separating surfaces can be visualized as continuing downward and under the younger terrace surface and deposit (see figs. 14 and 15). No fossils have been found in the deposits underlying these ter- races. This has been considered evidence of a non-marine origin for these features. It has been suggested (Antevs, 1929, p. 37), how- ever, that the absence of fossils may be due to leaching during periods when ground water levels were considerably lower. It might also be pointed out that these deposits could represent the extreme landward portions of areas of marine sedimentation, where overloaded streams contributing large amounts of sediment made a prolific fauna un- likely. Even if organisms were present the chances of preservation in such coarse materials would be poor. ORIGIN OF TERRACES Little actual work has been done on the stream terraces of Flor- ida. However, the origin of similar terraces occurring on Louisiana streams and associated with coastwise delta plains, has been dis- cussed by Fisk (1938, 1938a, 1939) and Russell (1940). They find each terrace to be underlain by a distinctive lithologic sequence, and each surface separated from succeeding younger and lower, and from preceding older and higher terraces by stream cut escarpments. These formational units and cut escarpments indicate at least five periods of cutting alternating with five periods of filling. These cycles are most easily explained by eustatic changes of sea level, as discussed by Fisk (1938, p. 67): "Eustatic changes in sea level progressed in definite cycles. Removal of water from the oceanic basins lowered the baselevel of streams and initi- ated erosion. The refilling of the basins raised baselevel and caused al- luviation of the stream valleys. The two events, a period of erosion followed by a period of deposition, constitute a cycle." Such large fluctuations of sea level have been correlated by Antevs (1928, 1929), Daly (1925, 1929), Fisk, (1938, 1939, 1940), Russell (1940) and others to cyclic glaciation of continental areas. Louisiana terrace deposits were correlated by Fisk (1938, p. 171, 1939, p. 187) with interglacial periods and rising base levels, while the periods of stream cutting were correlated with glacial periods and lowering base levels. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 27 In Louisiana four stream terraces, corresponding to four delta plains, have been recognized by Fisk (1938) and Russell (1940). Along the Atlantic Coast and portions of the Gulf Coast, however, Cooke (1925, 1930a, 1939) has recognized as many as seven coastwise terraces, which he believed to be of marine origin. Each of these marine plains, he believed, had a counterpart extending up streams. Cooke also considered the origin of these coastwise plains to be as- sociated with an intermittent rise and drop of sea level during eus- tatic adjustments to glaciation, though he introduces the concept of oceanic, deep development. Cooke (1925, p. 30) writes: "Each terrace indicates a long stand of the sea at a definite altitude with respect. to the land, during which the waves cut a wide or a narrow notch into the shore and with the debris from the land built up a platform in the deeper water off-shore. At the end of each such long period of sta- bility came a time of readjustment, when the land rose or the water level fell; the shore line retreated seaward and what had been the bottom of the ocean, became dry land." Cooke. is supported in the marine origin of these features by Shattuck.:.(1906, pp, 67, 137), Stephenson (1912, p. 272), Matson (1913, p. 32), Richards (1938) and others. Hays (1927, p. 279; 1928), however, believed the terraces of Florida and the Atlantic Coast to be largely the results of stream action, since, with the exception of the. lowest terrace, they lack all traces of marine organisms. The area of this report lies almost midway between the Louisiana area and the Atlantic Coast area. It is largely disassociated from the effects of the Mississippi delta, so that the theory of origin.. de- veloped by Fisk and Russell does not satisfy all of the facts with respect to the coastwise surfaces, though it does explain the s:treami surfaces, with the possible exception that there are four stream sur- faces associated, and one unassociated, with the .present drainage. The physiography of the coastwise surfaces compares favorably with the physiography of the present shore. Likewise, some of the evidence reviewed in the preceding section of this report favors a marine origin for these features. However, the local abundance of logs, leaves, stumps, and pollen, combined with the absence of marine organisms in these terrace deposits, suggests that the sediments might be of continental origin. It is possible that the coastwise deposits are marine sediments veneered with a continental facies. Such a relation- ship has not been discovered in these counties, however. The purpose of this study has been to point out evidence and not to advance a theory of terrace origin. In such a local area as Holmes. and Washington Counties it is impossible to solve all of the problems FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 connected with the coastwise and stream terraces. The writer feels that sufficient new evidence has been developed from the study of theEe counties to be of material assistance in arriving at a workable theory of terrace origin. Such a theory must satisfy all of the facts listed in this report. REGIONAL UPLIFT Terrace levels resulting from eustatic changes in sea level would not be separable today if all former strand lines occupied the same position. Cooke"1 believed the separation of these levels was due to the formation of oceanic deeps, combined with progressively smaller deglaciations, which resulted in corresponding eustatic changes in sea level. In other words, the formation of deeps resulted in each period of high sea level being lower than the preceding one, so that terraces were formed at progressively lower levels. Fisk (1938, p. 69, 1939, p. 199) and Russell (1940, p. 1225) resorted to epeirogenie uplift and regional tilting to explain why each surface has been differentiated and preserved in Louisiana. Fisk (1939, p. 194) rec- ognized two structural regions, both directly related to the Gulf Coast Geosyncline (Barton, Ritz, and Hickey, 1933): 1) an epeiro- genie uplift region inland from 2) the tilted region nearer the Mis- sissippi River delta. These features are discussed by Russell (1940), who also pointed out proof of the progressively higher terraces being progressively older. In western Florida no evidence of tilting was observed, as all the surfaces approximate the same slope. Advanced dissection in this local area, however, may obscure original slopes, and work elsewhere may show slight tilting. In these counties the major effect seems to have been epeirogenic uplift or ecstatic withdrawal of the sea, rather than regional tilting. Regardless of the underlying cause, epeirogenic uplift or a pro- gressive lowering of sea level has certainly been active in western Florida, as evidenced by progressively higher and older terrace slopes above the present sea level. STEEPHEADS Sellards (1918, p. 27) applied the local name "steephead" to unusual amphitheater-shaped valley heads occurring in high sand areas. He attributed their origin to spring sapping along poorly nPersonal communication, April, 1940. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 29 indurated beds underlying more consolidated sands. Sharp (1938, p. 247) agreed with Sellards and observed that drainage lines rarely lead from the upland surface into the steepheads. Cooke (1939, p. 17) stated that some of these "steepheads" might result from the stream capture of sink holes. Steepheads are natural features and in this area apparently have not resulted from accelerated soil erosion brought about by misuse of land. Most of them are between 100 and 200 feet wide. Steep- heads in Holmes and Washington Counties occur chiefly at the junction of recent drainage with relatively high land topped by thick deposits of terrace sands. Broad areas of sand absorb large Figure 9. Steephead in the SW14 sec. 13, T. 1 N., R. 16 W., near a fire tower. Picture taken looking lown a gully emptying almost at right angles into the steephead. quantities of water, thereby preventing effective run-off. This water emerges at the base of escarpments along the ground water surface as springs, which gradually migrate into the terrace levels. The steepness of the walls of these steepheads depends upon the relative induration of the sediments, and along the Choctawhatchee River south of Hinson's Crossroad, Washington County, they show all gradations from gullies with steep gradients to the typical steephead. The shape of the steephead is also governed by the positions of the springs which produce it. An amphitheater shape is due to a major spring joined by many side, or tributary springs. A typical steephead, easily accessible, occurs at Red Head, Wash- FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 ington County, on Highway 39. Along the escarpment facing Holmes Valley at Ebenezar Church Village, the bottoms of many good ex- amples go well below the Tertiary limestone and clay of that area. LIMESTONE SINKS The factors controlling the location of the many sinks in Holmes and Washington Counties make an interesting physiographic prob- lem. Sink locations (see fig. 7) appear to be due to initial irregu. larities, chiefly along old bay extensions, at the bases of coastwise scarps, along old stream channels, rim swamp streams, and swamps. Any of these original irregularities would tend to be preserved and even accentuated in this country because much of it is underlain by limestone, which is easily dissolved below any natural low where water accumulates. Thus the outlines of old alluvial deposits and patterns are preserved in the alignment of sinks. A good example occurs on the fluvial 10-20 Foot Surface along Holmes Creekl near Vernon, Washington County, where an alignment of sinks and swamps indicates the location of an old stream channel. The line of sinks on the coastwise 115-150 Foot Surface, roughly parallel to the escarpment separating the 60-105 Foot Surface from the 115-150 Foot Surface, possibly indicates an old bay or former drainage line, while Blue Pond and Crystal Lake are examples of sinks developed at the base of a scarp. These two have destroyed the scarp and have spread into both terrace levels. The extremely deep sink, called Falling Water, 31/2 miles south of Chipley, is a gdod example of a sink developed on an irregularity on the highest terrace level. When Falling Water Hill became an outlier, the ground water. surface was lowered so much that the sink was deepened. rapidly, forming a cylindrical opening about 75 feet deep. Two general types of sinks have been recognized in this area. One is the normal, steep-walled, round-bottomed sink, which may oir may not be filled with water. The others have broad, flat bottoms and are locally called "prairies" (fig. 10). They have little or no large vegetation growing on them. "Prairies" are formed by solution ac- tivity dissolving limestone down to the average ground water level and then spreading laterally. In wet seasons they become lakes 'and several may connect to form a system of interlocking lakes. During- dry seasons they drain underground. "The Deadens" and "Gully Pond Prairie", in southeastern Washington County, drain into Econ- fina Creek, and their subterranean river is easily traced in active GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FT0)RIDA 31 - *-7~ Figure 10. "The Deadens", a prairie developed upon the Ciancellaria zone of the Choctawhatchee formation in the NW' SW1 sec. 7, T. 1 N., R. 13 W. Hills of the 115-150 Foot Surface appear in the background. flows through shallow sink holes within the "prairie" proper (see fig. 19). The writer believes that these features are developed only if the average ground water level lies below the base of the cover- ing terrace deposits. Sinks are holes that have been slowly dissolved in limestone by downward-percolating ground water high in natural acids. Overlying unconsolidated materials are carried down into the sinks and thereby transported elsewhere as part of the load of the subterranean water. If the caverns and holes dissolved into the limestone become clogged Figure 11. Porter Pond in southeastern Washington County covers almost 2 square miles. The bottom of this sink lies well below the groundwater surface. Photo taken in the SW% SW/ see. 9, T. 1 N., R. 13 W., facing northeast. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 by impervious material, water may collect in the depression and form a lake. Likewise, if the sinks were formed at a time when ground water was extremely low, and if later the ground water surface rose, it would fill the 'sink depressions as lakes or ponds. The latter appears to have been the most common cause of lakes and ponds in this area. The drop and rise of groundwater probably is associated with changes in sea level during formation of the vari- ous terrace levels. Sinks are best developed on the coastwise 115-150 Foot and 170-220 Foot Surfaces. The conditions of formation apparently demand more time than has elapsed since the formation of lower plains. The coastwise 170-220 Foot Surface has existed long enough for the sinks to lower themselves into Tertiary sediments and they are now being slowly destroyed by the more recent drainage. Most of the sinks developed on the highest surface (250-320) have already been captured by later drainage and destroyed by erosion. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 33 STRATIGRAPHY INTRODUCTION The geologic formations found at the surface in Holmes and Washington Counties include strata ranging in age from upper Eocene to Recent. The oldest strata exposed belong to the Ocala limestone (Jackson group) and the youngest deposit found is the Recent alli- vium. Table 3 is a tabular summary of the formations as mapped and described in this study. Some evidence as to the age of older rocks underlying this area is afforded by a deep well drilled by the Chipley Oil Company at Falling Water Sink in the NW1/ NW1/ of see. 27, T. 4 N., R. 13 W., to a depth of 4912 feet. A log of this well prepared by E. H. Sellards and Herman Gunter (Mossom, 1926, pp. 195-204) indicated that Claiborne, Wilcox, Midway and Upper Cretaceous beds were pen- etrated. These beds were apparently identified largely by position and lithology as only five fossils are mentioned and none of these is a positive marker. Blanpied12 reported the Tampa from 5 to 50 feet, the Chick- asawhay from 50 to 125 feet, the Vicksburg from 125 to 155 feet, the Ocala from 155 to 365 feet, the Claiborne from 365 to 975 feet, the Wilcox from 975 to 2220 feet, the Midway from 2220 to 2540 feet, the Ripley-Selma from 2540 to 3420 feet, the Eutaw from 3420 to 4095 feet, and the Tuscaloosa from 4095 to 4912 feet in this well. In order to supplement the stratigraphic evidence gained by the examination of surface outcrops, and the logs of the few available water wells, the Florida Geological Survey drilled three test wells. These wells were drilled in critical areas, the locations being picked by the writer after considerable field work. Samples were obtained at five-foot intervals making it possible to accurately place the top of each formation. The locations of the wells and other data follow: 1) Gully Pond well: NE/4 NW1/ NE1/4 sec. 14, T. 1 N., R. 14 W., Washington County: Well curb elevation; 56 feet.l1 Total depth: 120 feet. Elevation of the top of each formation penetrated: Choc- tawhatchee formation (Cancellaria zone), at surface; Alum Bluff "Letter (November 16, 1938) addressed to Dr. W. Storrs Cole, filed with the Florida Geological Survey. "Unless otherwise stated all elevations given in this report were determined with a Paulin Altimeter. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 TABLE OF GEOLOGIC FORMATIONS IN HOLMES AND WASHINGTON COUNTIES SHolmes Washington County S Formation County S Alluvium present present E 4 0 10-20 Foot 10-20 Foot < 0 ) Deposits 30-50 Foot 30-50 Foot and the 60-105 Foot o a marked by 60-100 Foot' 60-100 Foot and the 115-150 Foot o definite 145-165 Foot, 145-165 Foot and the 170-220 Foot Levels 250-320 Foot 250-320 Foot Choctawhatchee absent West Washington East Washington formation Arca facies - Ecphora and Cancellaria facies Shoal River formation Alum Bluff group group 7 1 Chipola formation S Tampa present present formation Suwannee present present Limestone 0 E Marianna present present ad 2 limestone C 1 Ocala present present X 8 limestone TABLE 3 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 35 group (Chipola formation), 46 feet; Tampa formation, 20 feet; Su- wannee limestone, minus 20 feet. 2) W. T. Sheffield well: NW1/ NE1/ SEl/ see. 16, T. 2 N., R. 15 W., Washington County: Well curb elevation, 180 feet. Total depth, 180. feet. Elevation of the top of each formation penetrated: De- posits of the 170-220 Foot Surface at the surface; Choctawhatchee formation (Arca zone), 160 feet; Alum Bluff group (Shoal River formation), 93 feet; Alum Bluff group (Chipola formation), 78 feet; Tampa formation, 20 feet. 3) Walker Hamilton well: SE corner of the SW1/4 NW/4 SE1/4 sec. 24, T. 3 N., R. 18 W., Holmes County: Well curb elevation, 87 feet. Total depth, 200 feet. Elevation of the top of each formation penetrated: Weathered Alum Bluff group at surface; Tampa for- mation, 51 feet; Suwannee limestone, minus eight feet; 'Marianna limestone, minus 53 feet; Ocala limestone, minus 98 feet. Early deposition in these counties records a marine environment with the strand line lying to the north and west. Not until Miocene time does a non-marine environment make its appearance, and then only in the form of stream and possible delta extensions from the west. These extensions thin rapidly west to east, and simulate wedges between more typical marine deposits. Fisk (1938, p. 77) has pointed to the Coastal Plains of Texas as a region of active deltaic sedimentation throughout Oligocene time. Fisk says: "On the other hand, the Alabama-Florida section, representative of a region removed from continental sedimentation, is dominently marine. Many in- terfingering phases should be observed between the two extremes of con- stant sedimentary types." Following Oligocene time the strand line in Florida shifted south and east and Miocene deltaic and marine deposits interfinger. These counties apparently lay to the seaward side of the delta and rapidly changing conditions along the irregular margins produced a com- plicated sequence of faunas and sediments. This is especially true of the Alum Bluff group and the Choctawhatchee formation. The appearance of abundant gravel and coarse sands character- istic of the terrace deposits indicates a marked change in the sedi- mentary environment of these counties. Such deposits are known to be characteristic of the Pliocene and Pleistocene in other parts of the Gulf Coast and are so considered here. 36 FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 MAPS AND SECTIONS The outcrop pattern of the major divisions of rocks is shown on the appended geologic maps (plates I and II). The maps also in- clude the drainage, partial culture, and the location of all exposures and wells used in the descriptive text. Details of structure and stratigraphic positions of the various units are shown on two general geologic sections (fig. 13). In ad- dition 6 surveyed road profiles are used as a standard into which all nearby exposures, wells and other data were projected to give the cross sections represented by figures 14 and 15. Precise eleva- tions in the counties were obtained from. U. S. Coast and Geodetic Survey bench marks. In addition, state road and railroad profiles have been used. The elevations of isolated points were established with the Paulin Altimeter, using bench marks or known profile points as reference data. Otu .Illrlor Ot PIA *I1 UA - SS GENEVA -, IA^-lthi^^-::^ 11.' I I ] I I I I I l 1 1 t l I I ^l l"- l I I ' AL BAMA -UNTY - 11 ir-r r \ i r I -IF ----- lit -1 7 --)- -- -~ f^ I a = -* FA 1 R f I C1 l A. S- *- _W _--_- ..-JQ t I- - l~ ol! _.s Wrrr^T _. I I V"'- 3 .- I IALTOP VOUNT INDEX MAP TO GEOLOGIC SECTIONS 6-G'GENERAL SECTIONS S-s' SURVEYED PROFILES WITH PROJECTED EXPOSURES ' 1 I lH4Oh F-I l L LA 4D1 a ^>-ryfi~r- -----^. -. ^ *-4 ^^3"EI EN 1 ILI, I r= EN ::~i -. 4 Al .edP I E1.s6Al 0 1*, IoK i'L I (C$^ALILA E lTVL W I COUNTY E 0 RiW n RrW I R16W Rd W I __R4W_ i RiW Ie ReW. Figure 12. Index map to geologic sections. L1=L'I=7TB L i 11ii 11 iL*-Ek m1p I n~ -- --I- -- iv -. r --. -r~- rm - ~ ~~`-YYLYL~ -IL-- ~ --~-CICI~- I I- Dll I RwIW I ReW RtW I RITW I RIW RBW 1 RW !fq9A As,,Ilp&k GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 87 4-) cd 4) rn U2 <4 c 4> 0 c 4-1 ;4 U) cd cd (V0 03 Q rg d B w ed ;4 a 0 bi) SJ 02l .& 'o FI .r Q FLORIDA GEOLOGICAL, SURVEY-BULLETIN 21 IBI I n l " "i i I u^:: 8-: S 1 1' I5 I I Siii i ' '/ I I 4 4 vi I GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 89 i gj g ! I li I- Sw..^ -- ii' H i i *| ti*0 Jil I ~i I 14= woltum OWN::: FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 EOCENE SERIES Jackson Group Ocala Limestone Historical summary. The "Jackson formation" was described from exposures at Jackson, Mississippi, by Conrad (1855) under the "Vicks- burg group". Hilgard (1860, p. 128) referred these deposits to the Jackson group and noted that they were older than the Vicksburg group. Early naturalists considered all the white limestone of Florida to be a continuation of the Eocene limestones of Georgia and Ala- bama. The rock at Ocala, Florida, was referred to the Eocene by Le Conte (1861, p. 11) as early as 1861, and Smith (1881, p. 299) noted that the "Orbitoides limestone", including limestone at both Ocala and Marianna, Florida, probably crossed Holmes and Wash- ington Counties into westernmost Florida underneath the "stratified drift". In 1892 Dall (pp. 103, 104, 157) recognized in the Eocene of the Peninsula the "Orbitoides limestone" (Vicksburg), the "Nummulitic beds" (Ocala), and the "Miliolite limestone" (Ocala?), and con- sidered them to belong, at least in part, to the Vicksburg group. He (1892, pp. 103-104) named the limestone beds at Ocala, Florida, the Ocala limestone and correlated these sediments with the "Num- mulitic beds" and with the Oligocene of Heilprin (1887). Dall ob- served (pp. 103, 104): "Among the rocks which until recently were not discriminated from the Orbitoides limestone, and which appear in central Florida directly and conformably to overlie the latter, though no one has described their con- tact, is a yellowish friable rock containing many foraminifera, conspicu- ous among which are two species of Nummulites, N. willcoxii and N. floridana Hp. It is best displayed at Ocala, Florida, where it forms the country rock, and has been quarried to a depth of 20 feet without coming to the bottom of the beds." The "Peninsular limestone" was later suggested by Dall (1903, p. 1554) for part of the "Orbitoidal limestone", which apparently lay between the Vicksburg limestone and younger Ocala limestone. Matson and Clapp (1909, p. 51) placed the Ocala at the top of the Vicksburg group overlying the "Peninsular" and Marianna lime- stones, and referred this group to the Oligocene. This usage differed from all previous writers in recognizing the oldest rocks exposed in Florida as Oligocene. They based this age determination on a species of Nummulites identified by Heilprin (1882) as associated with the GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 41 Oligocene, and on Dall's (1903) work on the Tertiary faunas of Florida in which he lists the fauna of the Ocala and refers it to upper Vicksburg. Matson and Sanford (1913) adopted these con- clusions almost verbatum. It remained for Cooke (1915) to show that the Ocala is the equiva- lent in age of the "Jackson formation" of Alabama and Mississippi, and conformably underlies the Marianna of Florida. Subsequent writers have accepted Cooke's conclusions without question. Sellards and Gunter (1918a, p. 88) and Sellards (1919, p. 113) observed some "glauconitic calcareous sandrock" near the Alabama line in the bed of the Choctawhatchee River which they referred to the Claiborne Eocene. These beds are now known to be lower Jack- son and are discussed under the Ocala. Cooke and Mossom (1929, pp. 47-48) delimited the Ocala to include: "all the rock of Eocene age exposed in Florida, including the 'Orbitoidal', 'Nummulitic', and 'Miliolitic' limestones of Dall, as well as the 'Peninsular' limestone of Matson." One of the latest papers describing the Ocala is by Gravell and Hanna (1938, pp. 999-1006), who reported three faunal zones in this formation. From top to bottom these are 1) Discocyclina (Astero- cyclina) zone, including several species of Discocyclina and Lepido- cyclina ocalana Cushman, Operculinoides oaclana (Cushman), 0. willcoxi (Heilprin) and Heterostegina ocalana Cushman; 2) Oper- culina mariannensis Vaughan zone; 3) Camerina jacksonensis zone including C. jacksonensis Gravell and Hanna, C. moodybranchensis Gravell and Hanna, Operculina vaughani Cushman, Discocyclina flint- ensis (Cushman), and Lepidocyclina (Lepidocyclina) mortoni Cushman. The Ocala limestone of the present report includes all sediments bearing a Jackson group fauna that outcrops in Holmes or Washing- ton Counties. Physiography and outcrop pattern. The Ocala limestone is the only Eocene formation outcropping in H-olmes and Washington Coun- ties. All of northern Holmes County is underlain by the limestone which underlies a rugged, well-drained terrace topography, and which outcrops only along the major streams and tributaries. The outcrops occur intermittently down the Choctawhatchee River and its tribu- taries to the vicinity of Caryville, in Washington County, where the Marianna limestone overlies the Ocala. Notwithstanding its wide areal extent, there are few exposures. Slope wash and slumping of the terrace deposits obscure the formation except along active water channels. FLORIDA GEOLOGICAL SURVEY--BULLETIN 21 The Ocala outcrops only in the extreme northeastern corner of Washington County. In this area soil development and weathering have penetrated to such depth that exposures are rare. Solution fea- tures are common where terrace deposits do not protect the limestone. Several water wells, located in sec. 13, T. 5 N., R. 13 W., Jackson County, penetrated the Ocala after drilling thirty to forty feet of red clay, indicating that the limestone is present as mapped. Character of. materials. The Ocala limestone is divikable into two lithologic facies in this area. The lower facies is typically developed near Geneva, Alabama, but extends into northern Holmes County. It bears a lower Jackson fauna, and is a light greenish-gray, glau- conitic, sandy limestone, which grades upward into greenish-gray, thinly bedded, iron-stained sand, containing many molds of mollusks. The upper, and more typical facies of Ocala limestone is exposed along stream channels south of the outcrops of the lower facies. The limestone generally ranges from light yellow to white, but where weathered it may become silicified and the colors range from dark grays to yellow-gray. The limestone is typically massive, but is porous even when it has undergone silicification. These silicified areas resist erosion and form rapids along the main water courses. Some of the silicified portions have been incorporated into alluvial deposits as boulders. The two facies are in contact along a slightly irregular surface in an exposure just north of the Alabama-Florida line on the Choc- tawhatchee River. Thickness and structure. No exposure of the Ocala limestone in these counties exceeds a thickness of ten feet. Some estimate of the thickness of the Ocala may be made from cuttings taken from the Chipley Oil Company well near Falling Water Sink. The thickness in this well is 210 feet, and this agrees generally with the structural and outcrop patterns. The top of the Ocala limestone recorded in various wells indicate that the Ocala strikes west northwest and dips south approximately twelve feet per mile in Washington County. In Holmes County the dip increases to as much as 20 feet per mile and the beds strike northwest. The Walton Land and Timber Company well drilled by the Oil City Corporation at Rock Hill, Walton County, penetrated Ocala at a depth of 755 feet, indicating an increase in dip toward the southwest. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 43 Paleontology. The Ocala limestone is abundantly fossiliferous, however, macro-organisms are not numerous in these counties. Dall (1890-1903) lists over thirty species of macro-fossils from the type Ocala, but only Clypeaster rogersi (Morton), Pecten ocalanus Dall, and Pecten sp. cf. P. membranosus Morton were found in this area. The micro-fossils are, however, more abundant; 58 species of Foraminifera and 22 species of Ostracoda have been identified from the Ocala in Holmes County. These are listed in the checklists on pages 47-50. Local details. The lower glauconitic and sandy limestone phase is best developed just north of Holmes County near Geneva, Alabama. The following is a section, measured at the bridge over the Choc- tawhatchee River, on State Highway 12. Deposits underlying the 60-100 Foot Surface Feet 4) Red to yellow, cross-bedded sands with lenses of gravel at the base. Large boulders of silicified limestone containing many fossil molds occur in the gravel .................................................. ......................... 20 Ocala limestone 3) Greenish-gray, argillaceous, micaceous, unfossiliferous, very fine sand ...................................................................................................................... 15 2) Covered ......................................................................................................... 31 1) Greenish-gray (weathers buff), very fossiliferous, massive, sandy, glauconitic, granular limestone. It contains the large Ostrea trigonalis (Conrad) ................................................................................. 8 Water level T otal ................................................................. ................................ 74 . Bed 1 contains the following identifiable species of Jackson Foraminifera and Ostracoda: Foraminifera Angulogerina ocalana Cushman Bolivina jacksonensis striatella Cushman and Applin Cibicides lobatulus (Walker and Jacob) Eponides jacksonensis (Cushman and Applin) Glandulina laevigata ovata Cushman and Applin Guttulina austriaca d'Orbigny Nonion sp. cf. N. planatum Cushman and Thomas Nonionella hantkeni spissa Cushman Pseudopolymorphina dumblei (Cushman and Applin) Fextularia dibollensis Cushman and Applin var. Textularia mississippiensis Cushman Ostracoda Brachycythere watervalleyensis Howe and Chambers Oythereis gibsonensis Howe and Chambers Cythereis hysonensis Howe and Chambers Oythereis montgomeryensis Howe and Chambers Cythereis (?) jacksonensis Howe and Pyeatt Cytherelloidea danvillensis Howe Cytheretta sp. cf. C. alemanderi Howe and Chambers Oytheridea grigsbyi Howe and Chambers FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Gytheridea montgonwryensis Howe and Chambers Cytheridea (?) caldwelle)is Howe and Chambers Oytheridea (?) garretti Howe and Chambers Eocytheropteron spurgeonae Howe and Chambers Lowoconoha jacksolwnsis Howe and Chambers Paracypris franquesi Howe and Chambers Paraoytheridea bethavenensis Howe and Chambers Pyrioythereis isrealskyi Howe and Pyeatt From Geneva southward the river flows between 25 foot bluffs of this lower facies. Eight feet of bed number one is exposed at the Alabama-Florida line. Two and one-quarter miles below the Alabama line, approximately in the NW/4 see. 3, T. 6 N., R. 16 W., at an approximate elevation of 80 feet, the following section was measured. Locality H-36 Upper phase Feet 2) Dense white, silicified limestone with molds of Lepidocyclina sp. cf. SL. mortoni Cushman, and Pecten sp. cf. P. membranosus Morton .... 3.0 Lower phase 1) Blue-greenish gray, non-calcareous, argillaceous, fine, thin-bedded sand with molds of Jackson mollusks ............................................. 2.5 Total ................................................................................ ...... 5.5 Downstream from this exposure only the upper facies outcrops. Occasional exposures along the Choctawhatchee River consist of weath- ered and silicified limestone, which form rapids in the stream. Else- where along the channel the outcrop is covered by active river sedimentation. These rocks are not to be confused with boulders of silicified Suwannee and Vicksburg limestones, which are found oc- casionally in the banks of the river. The best exposures of the siliceous portion of the Ocala are found along the river in sec. 33, T. 5 N., R. 16 W., about three-fourths of a mile south of the mouth of Wrights Creek, and in the SW/4 SW/4 NE14 sec. 35, T. 7 N., R. 16 W. At the latter locality (H-6), approximate elevation 145 feet, there is a series of boulders of buff to white, porous, weathered, silicified limestone, containing numer- ous specimens of the following fossils: Xenophora sp. Ostrea sp. cf. 0. vicksburgensis Conrad (hlamys sp. cf. 0. diucanensis Mansfield Oypraea, sp. Pecten sp. cf. P. mnetbranosus Morton Stromb us sp. Polynices sp. Pitaria sp. The fauna is apparently a mixture of Ocala (') and Suwannee mollusks. Some of the boulders are undoubtedly part of the terrace GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 45 sequence, but the Ocala fauna could not be far removed from its original stratigraphic position. Fresh exposures of the upper faces of the Ocala limestone are associated with ledges of silificied limestone along the channel of Wrights Creek and its tributaries in central Holmes County. A thin veneer of floodplain deposits obscures the Ocala throughout the northeastern portion of the county, and the limestone is exposed downstream only where it is sufficiently resistant to extend up through the overlying deposits. At these exposures the Ocala lime- stone is a light yellow to buff, slightly sandy, very fossiliferous limestone. Where weathered it is dark brown to white, and silicified. The exposures are available only by boat, and are found approxi- mately at the following localities, essentially at water level. Figures in parentheses represent the approximate elevations. H-26: NW14 SE/4 sec. 32, T. 6 N., R. 14 W., (87 feet) 11-27: SW1i SW14 sec. 32, T. 6 N., R. 14 W., (84 feet) 11-28: NW1/ NE14 sec. 6, T. 5 N., R. 14 W., (83 feet) H-29: SE1/ NE14 sec. 1, T. 5 N., R. 15 W., (82 feet) H-30: NE1/4 SWl4 sec. 1, T. 5 N., R. 15 W., (80 feet) H1-31: SEiA NEl. sec. 3, T. 5 N., R. 15 W., (74 feet) H-32: NW1 SE1/4 sec. 13, T. 5 N., R. 16 W., (60 feet) H-33: NW1/ NW1/ sec. 26, T. 5 N., R. 16 W., (54 feet) H1-34: NW14 NW14 sec. 35, T. 5 N., R. 16 W., (51 feet) H-35: Cuttings from pile-borings for bridge in the NW1/4 NE1/4 sec. 10, T. 4 N., R. 16 W., (1 foot ?) These localities carry an abundant fauna, mostly micro-fossils. A faunal checklist of these exposures follows: FAUNAL CHECKLIST OF THE, OCALA LIMESTONE Symbols:- X Present at the locality 7 Questionably present at the locality FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Table 4 FAUNAL CHECKLIST OF THE OCALA LIMESTONE FORAMINIFERA Angulogerina ocalana Cushman.............. Buliminella elegantissima (d'Orbigny)........ Camerina sp.............................. . Cancris sp ....... ......... .............. Cibicides lobatulus (Walker and Jacob)........ mississippiensis (Cushman)............ sp....... ............... ............ sp. cf. C. yazooensis Cushman .......... Discorbis sp. cf. D. ocalana Cushman......... sp. ............. ................. . Eponides danvillensis Howe and Wallace ..... jacksonensis (Cushman and Applin)..... sp. cf. E. mariannensis (Cushman)...... sp. cf. E. ocalana Cushman........... ouachitainsis Howe and Wallace....... sp .................................. Globigerina sp............................. Globorotalia sp. cf. G. mencardii (d'Orbigny)........................ Globulina gibba d'Orbigny.................. gibba tuberculata d'Orbigny.......... minuta (Roemer).................... Guttulina irregularis d'Orbigny.............. problema d'Orbigny................... Gypsina sp ................................. Gyroidina sp............ ...... ........... Hantkenina alabamensis Cushman............. Karreriella sp............. ................. Lagena acuticosta Reuss..................... hexagona (Williamson).............. hispida Reuss............ ........ sp ............ ..................... sulcata (Walker and Jones)........... Lepidocyclina sp. cf. L. mortoni Cushman...... Lingulina sp............................... Marginulina cocoansis Cushman ............ sp.................... .............. triangularis d'Orbigny............... Massilina sp. cf. M. decorate Cushman........ Nodosaria sp. cf. N. vertebralis (Batsch)...... sp.................................. Nonion sp. cf. N. grateloupi (d'Orbigny)...... micrum Cole ....................... planatum Cushman and Thomas....... sp................. .... ....... x x x x x x x x x X X .. . . . . . . . . . . . . . . . X . . . . .. . , x x x X X x x x X X x x x x x x x x x x x x X X SCoN e n e o C4 c ff i.fi f fififf f x x x x x x x x x X X X x x x x x x x x x x x x X X x x x x x x x x x x x x x x x x x x GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 49 Table 4 (Continued) FAUNAL CHECKLIST OF THE OCALA LIMESTONE .--- I FORAMINIFERA (Continued) r4 n eei r e Opercilina mariannensis Vaughan.............. .. .. X .. .. X . ocalana Cushman................ X .. X .. .. X X X Reusslla sp.................. ... ... X .. X X ...... Robulus propinquus (Hantkcn)............... ... .. .. X X sp........................... ....... .. X X . Sigmomorphina semitecta (Reuss).............. .. .. .. .. .. .. X Siphonina danvillensis Howe and Wallace..... X .. .. sp................................... .. .. .. X X Spiroloculina sp ............................ .. ... .. .X X Textularia sp. cf. T. dibollensis Cushman and Applin ............. X .. .. .. X .. X X X mississippiensis Cushman ........ ...... .... X X X X X sp............ ..................... . X X .. X .. X X Trifaria bradyi Cushman ................. ... ... X .. X .. .. T'vbulogenerina jacksonensis Howe.............. .. .. X X X Uvigerina sp .......................... .. .. ...... .. X Virgulina dibollensis Cushman and Applin..... .... .. .. X . OSTRACODA Bairdiasp................................ X .. X X X X X X ? X Brachycythere watervalleyensis Howe and Cham bers... ................... .. .. .. ? .. .. .. Cythereis broussardi Howe and Chambers...... .. .. X hysonensis Howe and Chambers ........ X .. X X X .. X .. sp. cf. C. montgomeryensis Howe and Chambers ............. ...... ......... X Cytheteis (?) jacksonensis Howe and Pyeatt....... .. .. X X X X Cytherelloidea ouachitensis Howe.............. X Cytheridea grigsby Howe and Chambers ....... X .. .. .. X X .... Cytheridea () caldwellensis Howe and Chambers .. .. .. ? X... Cytheropteron montgomeryensis Howe and Chambers........... ....... ...... . X . Eocytheropteron spurgeona Howe and Chambers.. X Eucythere lowei Howe. ............................ ...X Hemicythere (?) sp ...................... X .. .. .. Loxoconchk creolenis Howe and Chambers .... X ? X X X sp.................................... .......... . Monoceratina n. sp........................ ........ .. .. X XX X X . Paracypris sp ........ ........... .. .. X .. .. .. .. X Paracytheridea belhavenensis Howe and Chambers.............. .... . Xestoleberis n. sp ........................... .. X I I I .. 50 FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Table 4 (Continued) FAUNAL CHECKLIST OF THE OCALA LIMESTONE MACRO-FOSSILS e fn l Pecten sp. cf. P. ocalanus Dall ................ .. .. .. .. X X .. .. X X membranosus Morton............... .... ? .. .. X .. .. .. .. .. Clypeaster rogersi (?) (Morton). .......................... X ...... X 1 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, F'LORIDA 51 OLIGOCENE SERIES Vicksburg Group Marianna Limestone Historical summary. Matson and Clapp (1909, pp. 51-52) sug- gested the name Marianna limestone for beds exposed at Marianna, Jackson County, Florida. Concerning these deposits they wrote: "The name Marianna limestone is here given to the soft, porous, light-gray to white limestones of western Florida, which are characterized by an abundance of Orbitoides mantelli and other foraminifera associated with many other fossils, prominent among which are Pecten poulsoni and P. perplanus." Some of the sections designated by Matson as Marianna have since been identified as Ocala and Glendon by Cooke (1915) and beds south of Chipley, Florida, called Marianna by Matson and Clapp (1909, pp. 57, 58) are included in the Suwannee limestone of this report. Cooke and Mossom (1929, p. 63) redefined the Marianna lime- stone as: "-the white limestone or 'chimney rock' that overlies the Ocala limestone at Marianna and carries Lepidocyclina mantelli and Pecten poulsoni." Cushman (1922, 1922a, 1923) has published three monographs on the fauna of the Vicksburg group, but unfortunately only two lo- calities in Florida were included in these. However, Cole and Ponton (1930) described the fauna of the Marianna limestone from nine localities in Florida other than the two mentioned by Cushman. Definition. The light gray limestone underlying Holmes and Wash- ington Counties that bears the Marianna fauna described by Cushman (1922a, 1923), and Cole and Ponton (1930) is mapped as Marianna in this report. Outcrop and physiography. The Marianna limestone underlies a low, evenly rolling topography, broken by solution features. The best exposures are found along the walls of sinks. The Marianna limestone was identified in Washington County by means of cuttings from water wells and its presence is also evidenced by projected geologic sections. It outcrops in a band up to three miles wide in the northeastern corner of Washington County, strik- ing in general west northwest. Along the major drainage the forma- tion is covered by younger deposits. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 In west central Holmes County the limestone again outcrops in a narrow band at the base of high hills capped by terrace deposits. The few good exposures in this area are significant as they are the first Marianna limestone outcrops reported from Florida, west of Jackson County. Lithology. The Marianna limestone is typically a light gray to cream foraminiferal limestone, with a massive appearance. Close ex- amination at some exposures shows extremely thin beds of sandy limestone. Species of large Lepidocycliia typify the limestone of any section, and individual beds may be largely composed of the larger Foraminifera. The rock weathers to a hard, pink, cavernous limestone, and with complete weathering and leaching red granular clays result. On fresh exposures the rock is so soft that ordinary wood saws are used to cut blocks widely used for buildings and chimney rock. These blocks case-harden upon exposure and are very serviceable for building purposes. Thicknless and structure. The Marianna limestone is generally of uniform thickness with only a slight thickening westward. Practi- cally the same thickness is found in these counties as at the type locality. Forty-five feet of Marianna was penetrated in the Hamilton well in the SE1/i sec. 24, T. 3 N., R. 18 W., and thirty feet in the Chipley Oil Company well near Falling Water Sink. Individual out- crops measure as much as thirty-six feet, whereas other exposures consist of only a few feet. The uniform thickness of the Marianna seems to indicate that it is conformable with the underlying and overlying formations. Elevations of the top of the Marianna limestone in wells and at exposures indicate that the bed strikes west northwest and dips gently southward about eleven feet per mile in Washington County, and strikes northwest and dips south approximately eighteen feet per mile in Holmes County. Paleontology. The Marianna limestone is characterized by an abundant fauna. The most prominent fossils are: Lepidocyclina tnantelli (Morton) Orthaulaw pugnam (Hellprin) Pccten anatipes Morton Oypeaster rogersi (Morton) Pcoten poulsoni Morton Ostrea vilc8sburgeAis8 Conrad Cole and Ponton (1930, pp. 22-23) recorded fifty-eight species and varieties of Foraminifera from nine localities in Jackson County. GEOLOGY OF IHOLMES AND WASHINGTON COUNTIES, FLORIDA 56 Although the Malrianuna limestone contains an abundant bryozoan fauna those of' the type local ty have never been described. T'ho f'ol- lowing species 0o Bryozon" are comiimon1 ill the Marianil. Adeonellopsf grtndll Canuu niid lhtshslrh I1'noplolomioella vallutl ('Unnu and hlsshlr E.cochocolac rugososa C(n1iu 1i1id llusslor I,'lorldina p1). laun uhria sp. Mlcrlbran Iporldra IpIa8lm11iuraills. ('UI I1111 nid lUnssler lSta inonoclla Infe rarlcul:ern Canu d linssler Sl'nganiiope llr vc'kburglicu Cinii d tli( M1isleir Slomacheicella cerslceolli.s Canu and llNShIer 'l'ubucvllaria vick'-bIrplca 'au amid IaNssler Likewise, hlie cst ieacodes of' tlhe i ,ype Mirialnnm liiestonle have never been de evried. 'The most. conmon described sleeies, oceclrring in the Maria'nna, are:1 ialr'dla, woodivlrdsl.s I lowe and Linw liaildoppilah Ilan'odonia IHowo and Limw irachl ll'lthererl1c rNI8ll lowve ( and Ienl COthelrein (?) kenlpl lHowe mind i lw OCItherein (?) mcguirl Iow S11t herenlla sp. Kritl hIiwnnI nalf. Ilowe n11d I ]il Para1'cllpri ro e'fici'denlss ( low'e llid IIW P'ontlovu)/pris (?) IinA'11iniIppic.ii Ilowlve I nud Ilnw JLocal Details. 'l'le IlIrimiala lim iestlone lies lt, orl' close Io lthe surface in niorlhtlieastern Wa;liniigtoll (,Contllly. 'I'le airei in(ellues roll- ing pine inds similar to lhie a I lalniin oitl.crop) lreon ill laekson County. Deep) clay soils hide t.he f()orlit.,iOil liin its pi'e once is ree- ogniized by imeaiis ol' (llitings .akenl front a water l well in the SW1/i Sh1/i see. 3, T. 4 N., R1. 13 W., on lthe (lainer Jal slll'face, buti, smpii lles of lie cutlins owelre, not snved '(. Li inleston ex- posed at, locnil.iy W-:34. hII few dist.illctive I'ossils anI cold be Vicks- burig, but it is pIa(ed inl the Stwlnlice limiestolne blecemise it contains al)undant lTcpidoc!yc'lin favosa, and L. unidosa. li',ewise, the M'lHi- aInn. niny lhave been( exposedI in a te.t :.; I)il dug nlt. locnlity W-27 (bed 1) in the N '/ SWi/i. sec. 3(, 'T. 4 N., i. 14 W., billt l be lso of th e lack ol' a disll tetive Mi riainnla f'ill and l e presence of' speOie- of SuiwanHie Ife.pidO(cycli' .lliis bed is nIso pclaed in the Sui\nniee liimestoile. Four I1eet of c(rePll, porous salndly lime stone is exp)osed at locality 11-5 on Little (0ui Creelk, one-qi ofe- a mile west of thIe lIath- away Mill, inl the NWI/I SIOl/I se 2(6, 'I. 5 N., It. 16 W., Ilolmines 4"Identfled by Drl. .IinICe II. McGIulrt, LoulSlllnut State IIIilvoCrlly. "Idcntifled by Dr, II. V. ITowe, Louilslnnn Stnfoe Tnlversiy. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 County at an elevation of sixty-two feet. The bed contains the fol- lowing fauna: Foraminifera Angulogorita byramenasi (Cushman) Bitubulogenerina sp. cf. B. hower Cushman Cibicides lobatulus (Walker and Jacob) Oibicides mississippiensis (Cushman) Discorbis sp. Eponfdes advena (Cushman) Eponides mariannensti (Cushman) Globulina gibba d'Orbigny Gyroidina vicksburgensis (Cushman) Karreriella sp. Liebussella byramensis (Cushman) Nonfon sp. Robulus sp. Hiphonina advena Cushman Ostracoda Bairdoppilata tamodonta Howe and Law iBthocypr18 sp. Cytherelloidea rosefieldensis Howe and Law Cytherella sp. Cythereis dacyi Howe and Law. Cythereis sp. Krithe hiwanneensis Howe and Lea This fauna is representative of the lower Marianna.1, The Marianna limestone overlies the Ocala limestone, and cut- tings from borings for the Caryville Bridge over the Choctawhatchee River (locality H-35) carry both a Marianna and Ocala fauna. The Marianna at this locality is covered by fifteen to twenty-five feet of alluvium. The thickest, but a somewhat sandy, exposure of Marianna in these counties occurs in a small sink in the NW1/ SE1/4 sec. 3, T. 5 N., R. 17 W., where the following section was measured. Elevation at the top of the sink is 156 feet. Locf Mar ility H-10 ianna limestone Feet 3) Red, sandy, clay soil enclosing scattered, hard, limestone boulders 10.3 2) Thin-bedded, cream to light gray, sandy limestone, with more massive layers interbedded. Contains numerous specimens of OCthcrelloidca sp., Elphidium poeyanuan (d'Orbigny), GOttulina problema d'Orbigny, Lenticulina sp., Lepidocyclina mantellt (Mor- ton), Nonion sp., Operculinclla dia Cole and Ponton, Robulus sp., Rotalia byramensis Cushman, Sigmonorphina sp., and Pecten, 2 sp. 15.9 1) Cream to light gray, massive, sandy limestone, which weathers cavernous. The following fauna was identified: Bolivina sp. cf. B. robusta H. B. Brady, Gibicidcs sp., Elphidium poeyanum (d'Orbigny), Eponides sp. cf. B. byramensis (Cushman), Lepido- cyclina mantelli (Morton), and Operoulinella dia Cole and Ponton 9.8 T total .................................................................................................... 30.0 t1F. Stearns MncNeil, U. S. Geological Survey, letter of May 27, 1941, reports Amualum ocalants Dall from the lower part of this outcrop, but the writer found none during subsequent visits. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 55 The upper beds of this outcrop resemble the Byram marl of Ala- bama in lithology and the two species of Pccten are closely related to the species of Pecten in the Byram.17 Similar rock is penetrated in all the wells of the immediate vi- cinity and seven feet of the hardened limestone is exposed in a sink one-fourth of a mile northwest of locality 11-10 at an elevation of 126 feet. The westernmost exposure of the Marianna limestone in Holmes County may be seen in a small sink on the N. C. Spears farm in the NEi/ NWl/4 SE1/4 sec. 26, T. 5 N., R. 18 W., at an elevation of 160 feet. The outcrop is covered by a foot of red clay and the sink is being filled by Mr. Spears to avoid erosion of his field. This is locality H-37 and the fossils present are: Operculinella dia Cole and Ponton, Canwris sagra (d'Orbigny), Cibicides sp. cf. 0. lobatulus (Walker and Jacob), Lepidocyclina mantelli (7) (Morton), Cytherelloidea byramensis Howe and Law, Cythereis (?) mcguirti Howe, and ten specimens identifiable only as to genera. In this vicinity water wells commonly penetrate limestone at shallow depths. Samples from the following wells contain a Mari- anna fauna. Approximate elevations of the samples are given in parentheses. 1) NWl/ NE1/ NE1/ sec. 11, T. 5 N., R. 17 W. (125 feet). 2) Padgett Farm in the SE1/4 SE1/ SE1/ sec. 22, T. 5 N., R. 18 W. (159 feet). 3) NE1/ NE1/ NW1/ sec. 22, T. 5 N., R. 18 W. (7150 feet) (two Byram species). Suwannee Limestone Introduction. The sediments mapped in this report under the tentative name Suwannee limestone constitute a distinct lithologic unit ranging from 50 to 70 feet in thickness. Because of the great number of species of Lepidocyclina which occur in the Suwannee, particularly such easily recognizable forms as L. undosa Cushman, L. gigas CuEhman var. duncanensis and L. yurnagunensis Cushman and varieties, most exposures of the Suwannee are identifiable on sight. The Suwannee is the most distinctive unit in the area. 1F. Stearns MacNeil, letter of May 27, 1041, believes the whole outcrop may be Byram. FLORI IDA GE~OLOG ICAL S URlt EY-B ULL~LETI N 21 The faunal content of the Suwannee varies from locality to lo- cality and the formation probably contains more than one paleonto- logical unit. Certain localities such as 11-11 contain some species of mollusks and foraminifer~; which have been previously reported only from the lower Cl'ckasawhay of eastern Mississippi. A few other localities such as W-34 contain small foraminifers which so far have been reported only from the Byram marl. Other localities such as 11-8 and W-46 contain a preponderance of species, particularly bryo- zoans, Iuggestive of the type locality of the Glendon limestone of Alabama. It is possible that lhe limestone mapped in this report as Su- wanlleC may represent a time interval equivalent to that required for the deposition of the Glendon limestone, Byram marl, and lower Chickasawhay marl of western Alabama and eastern Mississippi. It was impossible to e tabl'sh mappable units within the Suwannee in Washington and Holnmes Counties. While comparatively new, the term Suwannee has already been used for these deposits in Holhns and Washington Counties by Mans- field (1938, p. 99; 1940) and Cooke (1939a, p. 1560). Tlie original identification of the Suwannee limestone in this area was based on tile identti fiction of the molluscan fauna. The writer vi ited the type area of the Suwannee limestone and made extensive collections. There is a close s'milarity of the mollusks, collected in the type area, with those found in Washington and Holhncs Counties, although in both areas they are largely preserve:l as im- pressions. Species of Lepidocyclina and Operculino'des have not been found in the type area of the Suwannee limestone and the correlation between the two areas on the basis of Foraminifera, Bryozoa, and Ostraloda may be questionable because of the poor preservation of these organisms in the type Suwannee limestone. It may be that the unit mapped as Suwannee limestone in Holmes and Washington Counties is not the pree'se equivalent of the Suwan- nee in its type area. The writer, however, feels that the identifica- tion of Suwannee molluriks from some of the localities in Holmes and Washington Counties justifies the correlation. As the unit mapped as Suwannee cannot be satisfactorily divided in the field, he feels that it is better to possibly extend the use of the name than to in- troduce a new name for the deposits of this area. Historical summary. The Suwannee limestone is the mo.t recently GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 57 named Tertiary unit in Florida, and published works on it are few. Cooke and Mansfield (1936, pp. 71-72) wrote: "Tle 1mime 'Suwannee limestone' is proposed for yellowish limestone typi- cally exposed long (lihe Suwianel RItver in Florida, from Ellanvlle, where It ullconlf'ormillbly overlies white limestone conitaning Vicksburg (Oligocene) fossils, almost to White S)riings, near which It lies unc(onmforinmaly below tile Miocene HIiwllihorn formnaltion. Another Inlrgo nirca of Suwainee lime- stone, centering near Brooksville, IlIerildo County, lies between the Eocene Ocila liimesti.ne (on tle north) a11id the Miocene Tampa limeistolne (on the south). "Most writers have regarcded(l teli Siuwan e limestone is Ipirt ol' the Tampa liniestone. Tlhe writers think it is of late Vicksburg ge, becnluse it con- tains the ce(linold R1hfol cholamptus l/oi1ldii (Bouv'6). which Is kn(wnI else- where only in the late Vicksburg Flint: River formation, a1nd several species of Flint River mollusks. The l'resence of a sipectks of 1the foraniilnit'ral genus Coskhtolina (0. cookel Mobergo ) suggeKsts n age older ithlin Miocene. The S1uwannee liimestonIe is correlated tentatively with thl Flint River fcrimatiion of Georgin an d with the Chlckasnwhnly n11rl 1meimieir of the By3ram miarl of Mississippi, which occupies (lhe u)ppermnost known horizon of the Vicksburg group." The stratigralph'c unit to which Cooke and Mainsl'ield applied the name Suwuaiice limestone has been referred to many 1rm'nations in the past. )all (1892, p. 12.1) referred it to the T'ampa formation. Matson and Claipp (1909, pp. 73-74) called the deposits Ilawthorn (contemporaneous with the Chipola). In 1921 Hopkins (1921, p. 18) included them ill the Chattahoochee lime tone (Tampa, Mioccne). Mossom (1925, p. 74) placed the Suwannee in the Glendion (upper V:cksburg of' Cooke) and in 1.926 (p. 182) called it Tampa. Cooke and Mossom (1929) mapped the type area as Tampa. Mans'ield (1937) described the inollusks ofl the Tampa and Su- wannce limestones and pointed to significant (lifferelnces ill faunas. H[e says of' the Suwannee (p. 46): "The formation consists almost entirely of limestone. The unweathered rock is a granulnnr t1) dense, compact, usually cream-colored, rlatlir I)pre limestone. The lower part is at many places more granular than the upper." In a paper edited by Cooke and Gardner and published post- humously, Man field (1940) described and pictured the fauna of the Chickasawhay formation of Miississippi, and Cooke (p. 171) corre- lated the Suwancnee with the lower Chickasawhay marl. The Suwanvee liimeslone iv Holmes land lVWshinygton Counties. The outcrops considered in this report as Suwannee limestone have been mapped by prev'ou; writers under many different names. Mat- son and Clapp (1909, p. 58) considered the beds in the vicinity of Chipley, Florida, to be Marianna limestone. Cushman (1920) identified the following Ocala fossils from a FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 sample collected by G. C. Matson "six miles southwest of Chipley, on west side of St. Andrews Bay road". Lepidocyclina georgiana Cushman Lepidocyclina attenuata Cushman Lepidocyclina floridana Cushman Lepidocyclina ocalana var. subdecorata Cushman In 1929 Cooke and Mossom mapped these beds as Glendon lime- stone, and considered all of northern Washington and most of Holmes County to be underlain by the Glendon. Apparently they interpreted silicified limestone boulders, occurring in terrace deposits in Holmes County, as outcrops of Glendon limestone. Likewise in the 1929 publication Cooke and Mossom (p. 61) identified beds occurring near Duncan Church, Washington County, as Ocala limestone. From these beds, and from Matson's sample, six species, five confined to the Eocene, were listed by Cushman (1935). They follow: Tetiularia subhaurii Cushman Robulus gutticostatus (Gilmbel) Reussella eocena (Cushman) Angulogerina ocalana Cushman Eponides jacksonensis (Cushman and Applin) Eponides ocalana Cushman Cole (1934) preceded Cushman's 1935 publication with a paper confined to the Duncan Church localities and to the A. L. Parrish farm locality, three and one-half miles southeast of Wausau, Wash- ington County. He believed the species of Lepidocyclina at these places definitely proved them to be of Glendon age. He recorded the following fossils from these localities: Lepidocyclina supra (Conrad) Lepidocyclina yurnaguensis Cushman Lepidocyclina yurnagunensis var. morganopsis Vaughan Lcpidocyclina undosa Cushman Lepidocyclina undosa var. tunida Vaughan Lepidocyclina favosa Cushman Lepidocyclina gigas var. duncanensis Cole Cooke (1935, p. 1171) correlated the Flint River formation of Georgia with the limestone Cooke and Mossom (1929) had previously mapped as Glendon. At this time Cooke considered the ChickaEawhay marl to be a member of the Byram marl. Later he (1939a, p. 1560) treated the Chickasawhay marl as an independent formation and cor- related it with the Suwannee limestone of Florida and the Flint River of Georgia. Apparently Cooke thus considered the beds of western Florida that he had previously mapped as Glendon lime- stone to be equivalent to the Suwannee limestone. This was later confirmed by Mansfield (1938, 1940). GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 59 Definition. As used in this report the Suwannee limestone in- cludes all limestone beds lying below definite Tampa formation and above definite Marianna limestone. Physiographic expression and outcrop. The Suwannee limestone is characterized by solution topography with numerous sinks and ir- regularities which pre-empt or capture surface drainage. The many sink basins breaking terrace surfaces to the south of the Suwannee outcrops possibly owe their origin, in part, to the underlying Suwan- nee limestone. The Suwannee limestone forms the base of the hills south of Chipley and, due largely to rolling topography, outcrops in a broad band in northeastern Washington County. Along the major streams in western Washington County and eastern Holmes County, the Suwannee is covered by younger deposits. In west central Holmes County, the limestone is thinner and has steeper dips, so that it outcrops along a narrow band and the best exposures are in sinks. Lithology. The Suwannee is a light-gray to buff, porous, ex- tremely fossiliferous limestone. Locally the bed is a mass of large and small foraminifers. Elsewhere this faces is almost entirely re- placed by shells of mollusks in a crystalline limestone matrix. Partial weathering produces crystallization and a pink tint due to the incor- poration of iron oxide. Complete weathering produces a very red granular clay soil which supports profuse vegetation, where the for- mation is not covered by terrace deposits. The limestone contains many silicified masses which remain in the residual clays and some have been included as boulders in alluvial deposits. Some of these Suwannee boulders now in terrace deposits (localities H-20 and H-21) were originally calcareous, highly fossili- ferous sandstones. Thickness. The Suwannee limestone has a thickness of 45 feet in the well on the Hamilton farm in sec. 24, T. 3 N., R. 18 W. At least seventy-three feet of Suwannee is exposed in Falling Water Sink, and the samples taken from the Chipley Oil Company well at this locality indicate a slightly greater thickness. Other sections expose as much as fifty-four feet, but most sections expose only a few feet of fresh material. Variable thicknesses may possibly result from erosion preceding the deposition of the Tampa formation. Structure. The Suwannee limestone dips south, approximately ten FLORIDA GEOLOGICAL SURVEY-BULLETIN 21- feet per mile, and strikes west northwest across Washington County. In Holmes County the beds strike northwest and dip south approxi- mately twenty feet per mile. The Suwannee limestone equivalent near Pensacola, Florida, is found at a depth of approximately 1200 feet beneath overlying sediments indicating that the dip increases toward the southwest (Gravell and Ianna, 1938, p. 993). Paleontology. Mansfield (1937) li-ted thirty-four species of pele- cypods, thirty-two species of gastropods, one species of scaphopod, and one species of echinoid from the type area of the Suwannee. This fauna is quite closely related to that of the Tampa formation. Mansfield (1937, p. 48) listed only seven species and sub- species that are found in the Suwannee but not found in the Tampa. In Iolmnes and Washington Counties, all of the exposures, except those near Duncan Church, have an abundance of species of Oper- culinoides muirii Barker, wh'ch also occurs in the Byram marl of Alabama, and the type Glendon limestone. Other easily identified fos-ils such as LepidocyclinLa y.wr'agunensis Cushman and varieties occur only at localities H-17, W-27, W-32b, W-35 (bed 1), W-46, W-48 (bed 2), W-70 and in beds at Duncan Church. Lepidocyclina gigas duncanensis Cole has been identified only at localities H-8, \W-27, W-35 (bed 1), W-46, and in beds at Duncan Church. The Suwannee limestone at localities I-11 and W-35 (bed 2) contains few or no species of Lepidocyclina and is composed largely of molluscan impressions. The following mollu ks are distinctive and numerous in some of the Suwannee exposures of this area. Cardium brook.villense Mansfield Chione bain1bridgensis Dall Glycimeris smucamnensis Mansfield Kuphus inerassatus Gabb Orthaulax sp. cf. 0. pianam hlernandoensis Mansfield Peccen flintensis Mansfield Perten glendoncnsis Mansfield Pccten sp. cf. P. poulsoni Morton Local details. The Suwannee limestone outcrops in numerous sinks south of Chipley, Florida. The best known of these exposures is in Falling Water Sink in the NW1/4 NW1/4 see. 27, T. 4 N., R. 13 W., where the following section was measured. Locality W-38. Deposits underlying the 250-320 Foot Surfa'eo Feet 5) Red to yellow mottled sands and gravel wash ................................. 30.0 Tampa formation 4) Red to yellow, sandy clay soil with silicious nodules and float .... 20.0 3) Light greenish-gray. saccharoidal, argillaceous, sandy marl. En- closes thin lenses of fine green sand, a few pebbles, and a 3-4 inch oyster and Pecten bed ............................................... ............... .... 11.5 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 61 Suwannee limestone (elevation 143 feet) 2) Cream to .buff, granular, foraminiferal coquina in a limestone matrix. Fragments of macro-fessils are rare. Amphiteglina sp. of. A. chipolensis Cushman and Ponton, Misslssippina sp., 81- phonina sp. cf. S. advena Cushman, Gypsina sp., Reussclla sp., Bairdoppilata inartyni Coryell, Sample, and Jennings, Hemlicyhere sp., .Archicythereis n. sp., Lcpidocyclina favosa Cushiman. Lopdo- cyclinza undosa Cushman, and Operculinoides nuirii Barker are present ........................................................................... ........................... 1) Buff to light gray, granular, foraminiferal ccquina made up largely of Lepidocyclina favosa Cushman and L. uncosa Cushman, exposed in cave below sink floor. In addition to all the species of bed number two, BEphidium sp., Nonion grateloupl (d'Orbigny), Glypeaster rolgrsi (Morton), Ostrea vicksburgcnss8 Conrad, and Pect sp. were found .......................................................................... 08.0 4.3 Total .................- .................-------------------.---------.. ------..... 133.8 An outcrop in a small sink on the Gilbert farm in the NW14 see. 36, T. 4 N., R. 13 W., exposes the following section of the Suwannee limestone: Locality W-48 Feet 3) Red, granular clay with limestone float. Elevation 145 feet ........ 2.4 2) Buff, soft, foraminiferal ccquina. Weathers to light gray, crystal- line limestone containing numerous Lepidocyclina undosa Cush- man, L. yuriagiulcnsis Cushman, L. favosa Cushman, and Oper- culinella sp. cf. O. dia Cole and Ponton .......................................... 2 .5 1) Cream to buff, soft, granular limestone interbedded with, and grading up into, bed 2. It contains numerous molds of Orthaulua pulnaux hicrnladoensis Mansfield. Diplodonta ? sp., Curdium brook- villense Mansfield, Ampullina fliltensis Mansfield. "Amnauropsis" sp. aff. A. burnsii meridionalis Pilsbry. The following micro- fossils are also present: Hemicythere sp., Bairdoppilata sp., Gibicides sp., Globilerina sp., Baggyina wcnula Hadley, Elphi- dium rota Ellis, Nonion advenus (Cushman), Globulina libba d'Orbigny, Angulogerina sp., Reoussella sp.. Discorbis sp., Gypsina sp., Rolalia byramensis Cushman var., Siphonina aducma Cush- man, Eponidcs byramensis (Cushman), Lepidocyclina undosa Cushman, Lepidocyclina sp. cf. L. parvula, and Operculinoides m uirii Barker ............................................................. 1 .5 T total .............................................. ............................. .. .................... 48.4 In a test pit in the N1/2 SW1/4 sec. 36, T. 4 N., R. 14 W., the Marianna may have been reached. At this locality, W-27, the follow- ing section included the test pit, and was measured along an old road bed running northeast. The elevation at the top of bed three is 120 feet. Lcality W-27 Suwannee limestone Feet 3) Cream to buff, very soft, granular, large foraminiferal coquina limestone. Weathers to an indurated, crystalline, dense, cream limestone, and further to red, granular clay. Encloses many Lepidocyclina such as are in bed 2 of locality W-48 ................ 40.0 FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 2) Pinkish-gray to buff, soft, granular limestone with numerous Bryozoa and large Foraminifera ............................................................ 12.5 1) Pinkish-gray, soft, granular limestone, slightly harder than the overlying material. The fauna is something like Marianna.' As- sociated species of Lepidocyclina indicate it is Suwannee ............ 8.1 Total .............................................. .................. .................................. 55.6 The beds at Duncan Church lie at approximately the same ele- vation, one-quarter of a mile east of this outcrop. Much has been published regarding the limestone exposed in a sink on the A., L. Parrish farm in the SW1/4 SE1/4 sec. 33, T. 3 N., R. 13 W. Mossom (1925, p. 186) was the first to report this locality and he question- ably signed it to the Tampa formation and stated that it was cer- tainly older than the Chipola formation. The age determination was based on fossils identified by Miss Julia Gardner. Cooke and Mossom (1929, p. 96) recognized two facies and re- ferred both to the "Tampa limestone". Vaughan (Cole, 1934, p. 22) regarded these beds as middle Oligo- cene or Glendon and correlated them with the beds outcropping at Duncan Church. Mansfield (1934, p. 332) recognized two definite beds. The lower he believed to be the same as the limestone at Duncan Church, and the upper of indefinite age. However, after a study of the fauna at this locality, he (1938, p. 99) tentatively considered the upper bed as equivalent to the Suwannee limestone, and in part to the Chickasawhay. The lower bed he considered middle Oligocene. Later he (1940) definitely placed the upper bed in the Suwannee lime- stone and correlated it with the lower Chickasawhay of Mississippi. Locality W-35: Section in small sink back of the A. L. Parrish farm, Washington County. Locality W-35 Tampa formation? Feet 3) Red, sandy soil with small lime and silicious pellets ...................... 30.0 Suwannee limestone (elevation 66 feet) 2) Cream to light gray, saccharoidal, dense limestone with many fossil m olds .................................................................................................... 11.6 1) Cream to light gray, granular, foraminiferal limestone with many species of Lepidocyclina ........... ...................................... 9.3 T otal .......................................................................................................... 50.0 Mansfield (1934) reported twenty-eight species of mollusks from bed two. These were identified entirely from molds. This fauna was redescribed by him in 1940 and the list below is from his latest, posthumus, report. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 63 Anadara mummi Mansfield Ficus mississippiCnsis Conrad? *Anadara macneili Mansfield Kuphus incrassatus Gabb Oassis flintcnsis Mansfield Panope taylorensis Mansfield Ohione bainbridgensis Dall *Phacoides sp. f.f P. chipolana Dall Olava parrishi Mansfield Turritella sp. cf. 1. gatunensis Conrad In addition to these the following species have been identified by the writer from bed two. Ampullina sp. Oardium sp. cf. U. hernandoense Mansfield Oonus sp. aff. 0. imitator Brown and Pilsbry Corbula sp. cf. 0. burnsii Dall OlUvella sp. aff. 0. rmississippiensis Conrad Phos parrishi Mansfield *Semole sp. aff mithti Dall *8trombus sp. aff. S. liocyclus Dall Venericardia sp. cf. V. serricosta (Hellprin) With such poorly preserved specimens one can conclude that these show affinities with the fauna of the Suwannee limestone, but at the same time include many Tampa forms. The possibility that bed two is a transition facies between the Tampa formation and the Su- wannee limestone must be considered. Granting that all the identi- fications of the mollusks are correct, this possibility is strengthened. The species of Lepidocyclina from bed one have been described by Cole (1934), who implied that this bed contains the same fauna as the beds near Duncan Church. He assigned these beds to the Glendon limestone. A fresh, twenty-five foot exposure of Suwannee limestone can be seen in a sink on the T. A. Finch farm in the NElA NW1/ sec. 33, T. 4 N., R. 13 W. The following fossils occur at this locality (W-46). Foraminifera Oancris sagra (d'Orbigny) Oibicides lobatulus (Walker and Jacob) Discorbis byramensts Cushman Eponides sp. cf. E. byramensis (Cushman) Gypsina sp. cf. G. vesicularis (Parker and Jones) Lepidocyclina undosa Cushman Lepidocyclina undosa Cushman var. Lepidocyclina gigas duncanensis Cole Lepidocyclina yurnagunensis Cushman Nonion sp. cf., N. planatum Cushman and Thomas Operculinoides sp. cf. 0. muirti Barker Operculinoides sp. cf. 0. vicksburgensis Vaughan and Cole Reussella spinulosa Reuss var. Siphonina advena Cushman Bryozoa"8 Amphiblestrum rectum (Canu and Bassler) Canopeum sp. Enoplostomella sp. *Occurs in, or its closest relative occurs in, Tampa or younger beds. "Identified by Dr. James H. McGuirt, Louisiana State University. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Entalophora lunata (Canu and Bassler) Escharoides sp. cf. E.. erecta (Canu and Bassler) Filisparsa, 2 sp. Iloloporella scposita Canu and Bassler Idmonca grallator .Cann and Bassler Lichcnopora goldfltssi (Reuss) Mcnibraniporidra spissimturalis Canu and Bassler Michopora sp. Porella sp. ef. P. crassoparies Canu and Bassler Reotpora laciniosa Canu and Bassler Trypostcga sp. f. f venusta (Norman) Tubucellaria vicksburgica Canu and Bassler Locality W-34: Elevat'on: 128 feet. In a small sink in the NEI/4 NE1/4 sec. 14, T. 4 N., R. 13 W., thirteen feet of cream colored, very dense, crystalline limestone, largely a foraminiferal coquina, is ex- posed. The following fossils were identified: Amphistcgina sp. cf. A. chipolensis Mississippina sp. Cushmnn and Ponton Polyllorphina advena Cushman Operculinoides muirii Barker Reussella sp. Discorbis bylramensis Cushman Rotalia byranmensis Cushnan var. Lcpidocyclina favosa Cuslinan Snirillina sp cf vivipara Ehrenberg Lepidocyclina undosa Cushman Tectularia sp. The Suwannee limestone is expo-ed in many sinks in Washington County and can be studied at the following localities. The initials following each locality description indicate the fauna present: D. C. represents a Lep docyclina assemblage similar to that at Duncan Church, S. a fauna composed largely of molds of mollusks, G. a bryozoan fauna similar to that at Glendon, Alabama, and B. a Byram affinity. Locality W-28: 12 feet in an old quarry in the NW1/4 NW1/4 rec. 1, T. 3 N., R. 14 W. (D.C.) Locality W-29: 18 feet in road cut in the SE1/4 NE1/4 see. 16, T. 4 N., R. 13 W. (D.C.) Locality W-30: Well cuttings in the center of the SE1/ sec. 16, T. 4 N., R. 13 W. (D.C.) Locality W-31: 15 feet in abandoned quarry in the NE1/% SE1/4 SE1/ sec. 16, T. 4 N., R. 16 W. (D.C., G?) Locality W-32: 20 feet in a small sink in the NW1/4 SE1/4 sec. 16, T. 4 N., R. 13 W.. (D.C.) Locality W-33: 3 feet in road cut near the S1/4 of line of sees. 14 and 15, T. 4 N., R. 13 W. (D.C.) Locality W-47: 50 feet in a small sink in the NE1/4 NE1/4 sec. 32, T. 4 N., R. 13 W. (D.C., G., B., and S.) Local'ty W-70: 18 feet in road cut in the SW1/4 SW1/4 SW1/4 sec. 36, T. 4 N., R. 14 W. (D.C., S., B.) Approximately three hundred yards north of locality W-29 is an exposure of similar. limestone. A narrow outcrop of. this limestone GEOLOGY. OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 65 extends westward for at least a quarter of a mile, where it passes under terrace deposits. The Suwannee limestone was penetrated be- low these terrace deposits in R. B. Brown's well in the NW corner of the NW1/ SW1/ sec. 16, T. 4 N., R. 13 W. Within this band is the exposure described by Cooke (1923, p. 7) and Cooke and Mossom (1929, p. 70) as the Cedar Grove locality, and referred by them to the Glendon formation. At this place forty to fifty feet of buff, foraminiferal limestone is exposed in an amphi- theater-l haped sink. Lime reported by Cooke and Mossomi (1929, p. 71) outcrops at the abandoned Waldon lime kiln on the Alford Lumber Company land in the NE1/4 sec. 14, T. 4 N., R. 13 W., and at the Laney farm in the NE1/4 sec. 15, T. 4 N., R. 13 W. The easternmost exposure of Suwannee limestone in Washington County is found on tile farm of Alec Kent in the SW corner of the NE1/ sec. 9, T. 3 N., R. 12 W. This exposure consists of poorly fossiliferous rilicified boulders. There are few exposures of the Suwannee limestone in Holmes County. However, many s'liceous boulders occur throughout the county in the terrace deposits. Some of these are not far removed from their original stratigraphic position. The boulders found at locality --1 and 11-8 serve as examples. The boulders at II-1 con- tain rpecimens of Chlamys glendonensis Mansl'ield, which was de- scribed from the lower Chickasawhay. Boulders occurring on numer- ous hills in the vicinity of locality 11-8 contain a variedl fauna. These boulders were identified by Cooke as Glendon limestone (1923, p. 4) and they contain a Glendon faunal assemblage. In addition, however, they also carry faunas similar to those occurring in the Suwannee and younger deposits. They are interbedded with terrace sediments and if they are in place there must be a structural irreg- ularity between this outcrop and normal outcrops immediately south. For these reasons the boulders are believed to be part of the ex- tensive terrace deposits of this area, and w:ll be considered under the section devoted to those deposits. At locality H-11, in a small rink on the Hudson farm in the SW/4 NW1/ sec. 15, T. 5 N., R. 17 W., eight feet of cream to light gray, sandy, argillaceous limestone is expose:l. Harder white, crystal- line, very fossiliferous, sandy limestone layers are present. These beds contain the large Suwannee fauna listed below. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Foraminifera Amphistegina sp. cf. A. chtpolensis Cushman and Ponton Angulogerina sp. Baggina wenoula Hadley Operculinoides muirit Barker Oibicides sp. of. 0. choctawensis Cushman and McGlamery Cibicides sp. cf. 0. lobatulus (Walker and Jacob) Discorbis patelliformis (H. B. Brady) Dyocibicides biserialls Cushman and Valentine Discorbis sp. Elphidium sp. Globulina gibba d'Orbigny Lepidocyclina sp. cf. undosa tumida Vaughan Nonion sp. cf. N. grateloupi (d'Orbigny) Nonionella n. sp. Polymorphina advena Cushman Pseudopolnymorphina sp. Pyrgo subsphaerica (d'Orbigny) Pyrulina sp. Quinqueloculina sp. Re ussella spinulosa (Reuss) var. Rotalia byramensis Cushman var.? Sorites sp. Textularia sp. Triloculina sp. cf. T. trigonula (Lamarck) Virgulina sp. Ostracoda Bairdoppilata sp. cf. B. nartyni Coryell, Sample, and Jennings ylthereis (?) mcguirti Howe var. Oythereis sp. Oythercis sp. cf. 0. rosefieldensis Howe and Law Oythereis (?) vicksburgensis Howe and Law var. Cytherelloidea sp. (pitted) Cytheridca blanpiedi Stephenson Cytherideis sp. Cytheromorpha sp. Xestoleberis sp. Mollusca Chionc bainbridgensis Dall Kuphus incrassatus Gabb Chlamys glendoneisis Mansfield Pecten sp. cf. P. poulsoni Morton Glycymeris suwannensis Mansfield Limestone sinks and associated granular red soils are common wherever the Suwannee occurs near the surface in Holmes County; but the limestone is known chiefly from water wells. A limestone bearing a Suwannee fauna was penetrated in the following wells. Elevations of the samples are unknown. SE corner of the SE1/ SE1/ sec. 15, T. 5 N., R. 17 W. SW corner of the SEl/ SE1/4 sec. 15, T. 5 N., R. 17 W. SW1/4 NWl/4 SE1/4 see. 34, T. 5 N., R. 17 W. (beneath Tampa) NW corner of the SW1/ SW1/ sec. 23, T. 5 N., R. 18 W. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA .67 MIOCENE SERIES Tampa Formation Historical summary. Prior to 1888 many geologists had described the rocks exposed near Tampa, Florida: Conrad (1846, 1846a), Allen (1846), Bailey (1850), Tuomey (1851), Kerr (1885), Heilprin (1887), but none of these gave the deposit a name. The name Tampa formation was first suggested by Johnson (1888, p. 235) for beds exposed about some of the southern lakes, and Tampa and Hillsborough bays. Dall (1892, pp. 117-119) studied and gave more complete descrip- tions of the Tampa exposures and distinguished two facies which he named the "Tampa silex bed" and the younger "Tampa limestone". The lower bed was characterized by Orthaulax pugnax and was des- ignated the "Orthaulax bed", whereas the limestone was regarded as the possible equivalent of Heilprin's (1887) "Cerithium rock", named from the presence of many species belonging to that genus. Dall (1892, p. 112) included the "Tampa", "Chipola" and "Alum Bluff" beds in a "Tampa group". Later in studies made at Chat- tahoochee, Florida, he (1892, pp. 107, 115) discovered Orthaulax pugnax in deposits which he identified as the "Chattahoochee group" and in which he placed his "Silex beds". Both the "Cerithium" and "Orthaulax" beds were included in Matson and Clapp's (1909, pp. 84, 85) Tampa formation. The for- mation included a greenish-gray clay, at the top; the Cerithium bed; the Orthaulax bed; a limestone similar to the Cerithium bed; and more greenish-gray clay at the base. In general they described the formation as: "-greenish clays, light gray to yellow limestones, and a very fossiliferous bed of 'silex'" (p. 84). In 1929 Cooke and Mossom (p. 79) changed the name Tampa formation to "Tampa limestone" because the "formation consists almost entirely of limestone". They redefined the Tampa to include the Tampa formation of early workers, most of the "Chattahoochee", and part of the Hawthorn formation of Matson and Clapp (1909). The "Chattahoochee" section at Chattahoochee, Florida, was included "because it seems to be of the same age as the Tampa". Cooke and Mansfield (1936, p. 71) restricted the "Tampa lime- stone" as defined by previous writers and included the lower portions in their new Suwannee limestone. Mansfield (1937) followed with a FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 paper on the mollusks of the Tampa and Suwannee limestones and separated the two faunas. The "Tampa limestone" was considered equivalent to the upper Chickasawhay formation of Mississippi by Cooke in the paper by Mansfield (1940, pp. 171, 172) describing the "Mollushks of the Chickasawhay marl". Definition. As used in this report the term Tampa formation ap- plies to all sed'ments lying above the Suwannee limestone and below the Alum Bluff group. Unfos iliferous greenish-gray clays and silts lie between foss:l- iferous Suwannee limestone and limestone of the Tampa formation in the Hamilton well in sec. 24, T. 3 N., R. 18 W. Here, and in adjacent territory these clays and silts occupy the stratigraphic posi- tion that should be occupied by the Tampa formation. As the for- mation contains considerable amounts of this unfossiliferous clay and silt the term "Tampa limestone" i:; not entirely satisfactory. The writer, therefore, returns to the old usage of Tampa formation, but with Mansfield's paleontologic and stratigraphic restrict ons (1937). Outcrop and physiographic expression. The Tampa formation gen- erally underlies a region of high relief, but this surface configura- tion is controlled largely by overlying formations. Exposures of the Tampa are rare and the formation is mal)pped largely on the basis of structure. It outcrops at the base of the high hills in northeastern Wash- ington County, and extends westward along the valley of Iard Labor Creek in a broad band to Iolmes Creek. The formation outcrops along Iholmes Creek and the Choctawhatchee River in isolated ex- posures. Elsewhere along stream courses the formation i;' covered by younger terrace deposits. In western Holmes County the formation outcrops in a band four to five miles wide. The exposures in this area are usually at the base of hills. L.'thology and thickness. The Tamlpa formation i.; predominantly limestone in Washington County, but green argillaceous silts occur at the base of the section in Holmes County. A brownish-gray, very fossiliferous, granular limestone in southern and western Washington County grades northward into a greenish- gray, silty, fossiliferous marl. This latter may be seen at Falling GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 69 Water 'Sink and one-fourth of a mile north of Scott's Bridge over Econfina Creek in Bay County. Thirteen feet of the brownish-gray limestone overlying forty-six feet of green, calcareous silt, similar to that which outcrops through- out southwestern Holmes County, was penetrated in a well on the Hamilton farm in the SE1/4 sec. 24, T. 3 N., R. 18 W., Holmes County. This thickness of 59 feet appears to be the maximum in this area and the formation thins eastward to forty-two feet in the Gully Pond well, located in sec. 14, T. 1 N., R. 14 W. At Falling Water Sink in sec. 27, T. 4 N., R. 13 W., eleven feet of silty marl is exposed, although in 1914 Cooke (1929, p. 70) measured sixteen feet of this material. Geologic sections (figs. 13 and 15) indicate that the Tampa formation is approximately fifty feet thick in northern Washington County. A series of outcrops (W-3, W-4, W-5), one mile west of Hinson Crossroads, expose thirty feet of the brownish-gray limestone. The thickest section (16 feet) of the greenish-gray silt and clay is exposed on State Road 88, in the W1/2 see. 16, T. 5 N., R. 17 W. Structure. The Tampa formation dips south approximately twelve feet per mile and strikes west northwest across Washington County. In Holmes County the dip is approximately twenty feet per mile south and the strike is northwest. These figures are estimated from the elevations of exposures, combined with the elevations of the top of the Tampa formation in geologic test wells at three localities. (See figures 13 and 15). Paleontology. Mansfield (1937, p. 43) reported 306 species and sub-species of Mollusca from the Tampa formation. Only eight species and sub-species of the Tampa fauna are known in the fauna of the overlying Chipola, and only six species and sub-species exist in the Recent fauna. Of the Tampa fauna Mansfield (1937, p. 44) says: "The Tampa limestone fauna probably is more closely related to that of the Chipola formation than the above figures would indicate, as a number of other species in both horizons are closely related and were united by earlier workers. "--The high percentage of silica and the character of the fauna, which includes land and fresh water gastropods and the pelecypod Oyrcna, a genus now living in fresh and brackish water in Florida, indicate that the Tampa limestone was deposited in shallow water near the shore line." However, the faunal relationship of the Tampa to the Suwannee limestone is much closer than to the younger Chipola, as shown by -FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Mansfield's tabulations. Mansfield (1937, p. 48) listed 7 species and sub-species of Suwannee mollusks and echinoids which have not been reported from the Tampa. He (1937, pp. 48, 115-117) further in- dicated 22 species of marine mollusks from the Tampa "that have not been found with certainty in the Suwannee limestone." Gastropods make up a large percentage of the individuals in Holmes and Warhington Counties. Locally, however, oysters and pectens may predominate, as in the bed at Falling Water Sink, three and one-half miles south of Chipley.. Unfortunately, all exposures of the Tampa formation, with the exception of that at Falling Water Sink and at locality W-3, are so greatly altered by solution, that all molluscan fossils are molds. Accurate identifications are, therefore, difficult. In general, micro- fossils are better preserved and are similar to those of the Tampa formation of Wakulla County, which is one of the type areas of the formation. The Tampa of Falling Water Sink contains a number of ostracodes, such as Cytheridea blanpeidi Stephenson, C. howei Stephen- son and C. waynensis Stephenson, which, occur in the upper Chick- asawhay of eastern Mississippi. Local details. There are only six exposures of the Tampa forma- tion in Washington County. However, these are supplemented by a number of water wells from which samples were obtained. The best known locality of the Tampa formation (W-38, bed 3) is at Falling Water Sink in the NW1/4 sec. 27, T. 4 N., R. 13 W. (section on pages 60-61), where eleven feet of fresh, argillaceous, sandy marl is exposed. Cooke and Mossom (1929, p. 96) reported the following fossils from this bed. Sorites duplex (Carpenter) Pecten anguillensis Guppy Ostrea vicksburgensis Conrad Pecten gardnerae Cooke Ostrea sp. Pecten crocus Cooke Pecten sp. cf. P. gabbi Dall To these Mansfield (1937, p. 39) added the following and ob- served that the Ostrea vicksburgensis Conrad is perhaps closer to 0. rugifera Dall. Ceritlhum. sp. aff. C. precursor Dall Amusium sp. Ostrea caducaqua Mansfield Modiolus blandus Dall Chlanlys sp. aff. C. crucianus Cooke Ohione sp. aff. U. spenceri Cooke Three forms new to this locality, Celliforma nuda (Dall), Coelo- pleurus sp. cf. C. sloani Clark, and Ampullina sp., were found in this bed by the writer. In addition, the following micro-fossils were identified: GEOLOGY OF HOLMES AND. WASHINGTON COUNTIES, FLORIDA 71 Foraminifera Angulogerina sp. Globulina gibba d'Orbigny Archaias sp. Hauerina sp. Bolivina sp. cf. B. plicatella Marginopora (or Sorites) sp. Cushman Massilina sp. Bolivina sp. Quinqueloculina seminula (Linne) Oibicides sp. Quinqueloculina, 3 sp. Discorbts, 3 sp. Reussella spinulosa (Reuss) Elphidiumn sp. cf. E. chipolenvis Rotalia byranWensis Cushman var. (Cushinan) Trtloculina, 2 sp. Elphidium rota Ellis Triloculina trigonula (Lamarck) Ostracoda Bairdoppilata sp. cf. B. martyni Coryell, Sample, and Jennings Bythocypris (?) sp. of. B. gibsonensis Howe and Chambers Cythereis sp. Oythereis (?) vicksburgensis Howe and Law var. Oytheretta sp. Cytheridea blanpeidi Stephenson Cytheridea hotwel Stephenson Cytheridea waynensis Stephenson Cytheronorpiha sp. Eocytheropteron sp. Hemicythere n. sp. Loxoconcha sp. Paracypris sp. Paracytheridea sp. Pyricythereis sp. Xestoleberis sp. A small 2 foot ledge of light gray, very dense, sandy limestone outcrops on the bank of Holmes Creek in the center of sec. 3, T. 2 N., R. 16 W. It contains two molds of Clava sp. cf. C. parrishi Mansfield and is probably Tampa in age. One mile west of Iinson Crossroads there is a series of exposures of the limestone of the Tampa formation. These beds were mapped as Glendon limestone by Cooke (1929, p. 70), who apparently never saw the outcrops, but identified some chimney rock reportedly taken from these exposures. Locality W-3: In the road bed in the SW corner of the NE1/4 sec. 17, T. 3 N., R. 16 W. The outcrop consists of a four foot bed of very plastic gray clay containing many shells of Ostrea sp. of. 0. rugifera Dall, and 0. normalis var. caducaqua Mansfield. Locality W-4: On the Choctawhatchee River escarpment in the NE corner of the NW1/4 NE1/4 eec. 17, T. 3 N., R. 16 W., there is a ten foot exposure of pinkish-gray, finely crystalline, dense lime- stone interbedded with porous, mealy textured, argillaceous limestone. Weathering produces a granular ied clay with a soft, flaky siliceous residue. Locality W-5: In an old quarry on the Choctawhatchee River FLORIDA GEOLOGICAL SURVEY-BTULLETIN 21 escarpment in the SE1 SE1/4 sec. 8, T. 3 N., R. 16 W. The eleva- tion at the top of the Tertiary is 50 feet. Locality W-5 Deposits underlying the 60-100 Foot Surface Feet Coarse pebbles and poorly sorted sand in a red clay matrix ................ 70.0 Tampa formation Cream to light-gray colored, dense, finely crystalline limestone, which weathers to limestone granules and to granular clay. Corals and molds of the following Mollusca are abundant: Cardium berberun Dall, Cardium gadsdenenso Mansfield, Clava sp., Divaricella sp., Ostrea sp. cf. 0. rugifcra Dall, Phacoides sp. cf. P. chipolanus Dall, Urosalpinx ? hillsboroensis Mansfield. The bed contains an upper Chickasawhay-Tampa micro-fauna similar to the Tampa of locality W -38 .......................................................................................................................... 15.4 T otal .......................................................................................................... 85.4 The Tampa formation was penetrated in the following wells: 1) A well 29 feet deep (locality W-78) located in the center of the SWi/4 see. 27, T. 3 N., R. 14 W., Washington County. The last foot in this well penetrated greenish-gray limestone carrying a Tampa fauna. The well curb elevation is 115 feet, and the well is located at the base of the greenish-gray Alum Bluff silt at locality W-73. 2) A well (locality W-79) located in the SW1/4 NE1/4 sec. 23, T. 3 N., R. 14 W., Washington County. This well is 45 feet deep; the last five feet penetrated white, fossiliferous limestone containing Tampa fossils. Elevation of well curb, 120 feet. 3) The Gully Pond well (see fig. 13) in the NE1/4 sec. 14, T. 1 N., R. 14 W., Washington County, penetrated forty feet of Tampa for- mation, starting at an elevation of twenty feet. 4) The Sheffield well (see fig. 13) in the SE /4 sec. 16, T. 2 N., R. 15 W., Washington County, bottomed in Tampa formation after penetrating twenty feet of the formation. Elevation of top, twenty feet. 5) The Hamilton well (see fig. 13) in the SE1/4 sec. 24, T. 3 N., R. 18 W., Holmes County, penetrated fifty-nine feet of Tampa forma- tion, starting at an elevation of fifty-one feet. In Holmes County the basal green clays and silts of the Tampa formation are exposed at numerous places, but at these localities they are leached of their calcareous content. The best section is in a road cut on State Road 88, in the NW corner of the SW1/4 see. 16, T. 5 N., R. 17 W., where 16 feet of the deposit is exposed. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 73 Other places where the greenish-gray silt and clay faces of the Tampa formation may be seen are: SW corner of the NE1/4 sec. 29, T. 5 N., R. 17 W., in cut on State Road 88. Road cut in the NE1/4 SW1/4 sec. 8, T. 5 N., R. 17 W. Road cut in the center of the SW1/4 sec. 4, T. 5 N., R. 17 W. Along the hill west of the road in the NW1/4 sec. 14, T. 5 N., R. 17 W. Alum Bluff Group Historical summary. Langdon (1889) was the first geologist to study and describe the section at Alum Bluff, Florida. His section (p. 322) included the sediments now referred to the Alum Bluff group, and to the Choctawhatchee formation. Later he (1891, pp. 91-97) included all of these deposits under the "Alum Bluff series". Cooke and Mossom (1929, p. 138) have apparently misunderstood his section as they reported these beds described by Langdon as the Choctawhatchee formation, asserting that the beds now called Alum Bluff were under water at the time of Langdon's visit. However, comparison of the description of the section at Alum Bluff by Cooke (1929, p. 108) with that by Langdon (1889, p. 322) indicates com- parable lithologic units. Dall (1892, p. 122) did not make reference to Langdon's 1891 paper as he used the "Alum Bluff beds" to include only those un- fossiliferous transitional sand and clay strata lying above his "Chipola marl" and below the upper fossiliferous "Ecphora bed" at Alum Bluff. He thus recognized the "Chipola marl" as the lowest exposed rock. While tracing the "Chipola marl" westward, Dall and Stanley- Brown (1894, p. 166) discovered the deposits at Oak Grove, Florida, on the Yellow River. They noted that: "-what appears to be this same fauna occurs in a fine incoherent gray sand, with a number of species not found in the Chipola marl, including the Turritella (n. sp.) referred to as occurring at Rock bluff." They believed this fauna to be slightly younger than the "Chipola marl", and referred to the deposit as the "Oak Grove sand". Dall and Stanley-Brown (1894, p. 167) recognized a "Chipola series" and included in it "the Chipola Marl, the Roberts, Escambia County, Alabama sands and the Alum Bluff beds-." FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 The "Chipola epoch" (Dall, 1897, p. 330) and the "Chipola group" (Foerste, 1893, p. 244) were suggested as group names, but Matson and Clapp (1909, pp. 67-68) discarded these names and in- troduced the term "Apalachicola group", which included the partly contemporaneous Hawthorn, Chattahoochee, and Tampa formations, and the Alum Bluff formation". The "Alum Bluff formation" in- cluded in descending order a new Shoal River marl member, described by Vaughan; Dall's Oak Grove sand member; and Dali's Chipola marl member. The Alum Bluff was raised to the rank of a group by Gardner (1926, p. 2). Its type locality was set at Alum Bluff, Florida, and it was divided in descending order into the Shoal River formation, the Oak Grove sand, and the Chipola formation. The Chipola and Shoal River formations were redescribed by Gardner so as to include deposits other than those of the original descriptions. The Alum Bluff group in Holmes and Washington Counties. The name, Alum Bluff group, is used in the sense of a formation, a mappable unit, in this report. It includes all beds lying stratigraphically be- tween the Choctawhatchee formation and the Tampa formation. West- ward these beds probably include the three formational units recog- nized bly Gardner; the Shoal River formation, the Oak Grove sand, and the Chipola formation. The Alum Bluff group is represented solely by the Chipola for- mation in eastern and southern Washington County. Westward, the group thickens and wedge shaped deposits, some of which have char- acteristic faunal elements, make their appearance (see fig. 13). The Shoal River formation represents the youngest of these wedge shaped deposits and carries a characteristic fauna. It makes its first ap- pearance in central Washington County and thickens abruptly west- ward. The Oak Grove sand has not been found either on the outcrop or in wells in the area mapped. It probably represents a similar wedge-shaped deposit which first appears in Okaloosa County to the west of Holmes County. Gardner's work (1926, p. 1) in western Florida showed that: "Although there is no known section where the three faunas (Chipola, Oak Grove, and the Shoal River) are present, there is no question that the Oak Grove fauna is intermediate between the Chipola fauna and the Shoal River fauna." She (1926, p. 2) raised the Alum Bluff formation to the rank of a group: ". not merely because the faunal differences between its subdivisions are too great to be included within a single formational unit but because 74 GEOLOGY OF HQLMES AND WASHINGTON COUNTIES, FLORIDA 75 of the implied significance of the shifting in the strand line and ocean currents necessary to bring about so marked a change in the life." It seems to the writer that the Alum Bluff units are simply faunal divisions, and he questions their usage as mappable formations. Whether the Alum Bluff sediments constitute a single mappable for- mation in the area considered in this report and a group consisting of three formations elsewhere must await detailed mapping in Wal- ton and Okaloosa Counties. While the Alum Bluff is mapped in the sense of a formation in this report, the term, Alum Bluff group, is used in order not to further complicate the stratigraphic literature. Outcrop and physiographic expression. The Alum Bluff group has a dendritic outcrop pattern in southwestern Holmes County, (see plate I) where it is exposed in deep, narrow valley walls, beneath the highest terrace deposits. The outcrop swings down the Choctawhatchee River and Holmes Creek where shallow-water marine sediments are exposed along the stream banks. The continuity of springs and seepages at the base of the terrace deposits along the floodplain escarpment of Holmes Creek indicates that these Tertiary sediments are present as far upstream in central Washington County as Miller's Ferry. The group is mapped at the base of the "Holmes Valley Escarpment" (see page 6) chiefly because of projected Tertiary sections and in the presence of weathered clays. In the vicinity of Norum, and east of Vernon, Washington County, the outcrop broadens and the Alum Bluff sediments outcrop in a series of smoothly undulating hills. Many good exposures occur in road cuts through these hills. East of Wausau, central Washington County, the Alum Bluff group has been weathered to deep, red, clay soils, which contain small white sandstone clusters. Two other outcrop areas occur in Washington County. Fossilifer- ous Alum Bluff sediments carrying a Chipola fauna outcrop along the very deep Econfina Creek bed in southeastern Washington County. Non-fossiliferous greenish-gray silts and sands outcrop in the high hills of northeastern Washington County. They are best exposed at Rock Hill, where good drainage has favored silicification of theFe silts and sands. Lithology. It is almost impossible to distinguish the sediments of the upper Alum Bluff group from those of the Area zone of the Choetawhatchee by means of lithology alone. In fresh exposures the FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Alum Bluff sediments consist of marl, sand, clay, silt, and limestone. These beds are fairly distinct, but are gradationally interbedded. In southern and eastern Washington County a brownish-gray, highly fossiliferous limestone, carrying a Chipola fauna, grades west and north into a shallow-water coquina sand, which is interbedded with overlying fossiliferous blue clays. The Alum Bluff group of northern Washington County consists largely of an unfossiliferous green, ben- tonitic (?) siltstone. Sediments carrying a Shoal River fauna in Washington County are a complicated sequence of yellow micaceous sands, gravels, and mottled blocky clays containing many molds of shallow-water mud- living organisms. In Holmes County a bay deposit of carbonaceous clays and fine silty sands containing Shoal River mollusks overlies a basal beach cand and underlies a greenish-gray, argillaceous shell sand containing a characteristic Shoal River molluscan fauna. Thickness and structure. The thickness of the Alum Bluff group is extremely variable but reaches a maximum of at least 130 feet in Holmes County. Eastward the group thins rapidly into true marine faces and has a thickness of only 30 feet in the southern part of Washington County (see fig. 13). This marine deposit con- tains a Chipola fauna and is immediately overlain by the Choctaw- hatchee formation. The geological sections (figs. 13, 15) show that the Alum Bluff thickens northward to 56 feet in the vicinity of Falling Water Hill, where green bentonitic (9) siltstone is exposed. In the Sheffield well in central Washington County the Alum Bluff group is 73 feet thick. The upper 15 feet consists of gravel which contains a Shoal River (?) oyster and Pecten reef at the base, the lower portion carries a Chipola fauna. The Alum Bluff beds strike west northwest and have a gentle south dip of approximately ten feet per mile in Washington County. The beds strike northwest in Holmes County, and the dip increases sharply to approximately 18 feet per mile, south. Paleontology. The Alum Bluff group contains a distinctive fauna which has been subdivided into three closely related faunal units. Many species confined to one formation have analogues in each of the other formations. It is the writer's opinion, therefore, that the differences in faunas within the group could result from different ecological facies of the same time interval. For instance, the la- goonal fauna of today differs from the open water fauna as a result of a difference in water temperatures and a more protective en- 76 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 77 vironraent. The presence of three interpreted faunas in the Alum Bluff group of western Florida and only one in eastern Washington County may simply indicate that the variable ecological conditions to the west were represented by uniform conditions in eastern Wash- ington County during the same period. The writer believes that both faunal and lithologic studies indicate that the Chipola formation in eastern Washington County may be the same time equivalent of the Chipola, Oak Grove, and Shoal River formations to the west. Numerous papers listed in the bibliography record the various faunas occurring in the Alum Bluff group. The most important of these is by Gardner (1926 to 1937). Foraminifera occurring in the Alum Bluff deposits of Holmes and Washington Counties are included on the checklists of Miocene Foraminifera on pages 121-127 of this report, along with those oc- curring in deposits of the Choctawhatchee formation. A molluscan checklist of the Alum Bluff localities described in the text is included on pages 87-95. Local details. Econfina Creek in western Washington County flows approximately along the contact of the Chipola portion of the Alum Bluff group and the Choctawhatchee formation. Many fresh expos- ures are found along the stream bed. Locality W-59: Approximately one-fourth mile north of Gainer's Bridge in the SE1/4 Fee. 33, T. 1 N., R. 13 W., there is a five foot exposure of indurated, reddish-brown, coquina sand. Four feet of similar sediment outcrops at locality W-56, one mile above Gainer's Bridge in the SW1/4 sec. 27, T. 1 N., R. 13 W. Locality W-55: Approximately one and one-half miles above Gainer's Bridge over Econfina Creek in the SW1/4 sec. 27, T. 1 N., R. 13 W., at water level, there is three feet of weathered, reddish- brown, white speckled, coquina sand, which contains a Chipola fauna. Southward downstream this same sand is exposed at several points essentially at water level, but at these places the shells have all been leached and only molds remain. Casts of these molds have an affinity with the Alum Bluff fauna. Locality W-53: Approximately one-fourth mile below Walsing- ham Bridge over Econfina Creek in the NEl/4 see. 22, T. 1 N., R. 13 W., the following section was made: Locality W-53 Ohoctawhatchee formation Feet 2) Buff to yellow to red, weathered, granular clay ................................ 25.3 FLORIDA (GEOLOGICAL SURVEY-BULLETIN 21 Alum Bluff group (Chipo,;a formation) 1) Ledge of wenlierctd blue-green, fossiliferous marl below water level. Sample W d3 ....................... .............................................................. 2.0 Total .................................................... 273 Unweathered exposures of sediments similar to the marl, bed 1 of locality W-53, are exposed in Bay County. Because a study of these exposures is essential to the understanding of the Alum Bluff sedimentary history, two of these localities are listed. Locality B-7: Approximately one mile below Scott's Bridge, in the SE1/4 sec. 21, T. 2 N., R. 12 W. Locality I-7 Alum Bluff group (Chipola formation ?) Feet 2) Greenish-gray, micaceous, fine sand with many molds of fossils heretofore reported as confined to the Chipola or to the Shoal River .... 5.4 Alum Bluff group (Chipola formation) 1) Dark greenish-gray, very fossiliferous, sandy marl, with carbona- ceous wood fragments and leaves. (Sample B-7) ..................................... 4.5 T total ......................... .......................... 9.9 The marine coquina sands of southern Washington County can be traced in almost continuous exposures along Econfina Creek into the littoral facies and possible i: nal faces represented by the carbonaceous marl of locality B-7. A fresh exposure of bed 2 of locality B-7 outcrops approximately one and three-fourths miles below Scott's Bridge, in the NE1/4 see. 28, T. 2 N., R. 12 W. Shells are present in six feet of greenish-blue, argillaceous, fine _rand. The following fossils were identified. The stratigraphic range of each (Gardner, 1926 to 1937) is given in parentheses. Oardium taphrliun Dall (Shoal River) Chione burnsii Dall (Chipola) Corbula funiakkensis Gardner (Shoal River) Diplodonta glos Gardner (Chipola) Leda proteracuta dystakta (7) Gardner (Chipola) Nucula chipolana Dall (Chipola, Shoal River) Phacoides calhounensis Dall (Chipola, Oak Grove) Turritella gatiuensis blountensis Mansfield (Area, Shoal River) Yoldia frater Dall (Chipola, Oak Grove, Shoal River) The sand also contains a micro-fauna of Alum Bluff age. Although distinctive micro-fossils are absent, most of the species occur in the basal beds of the Alum Bluff group. The study of the sediments and the faunas of the Econfina Creek outcrops has led the writer to believe that beds bearing a Chipola fauna in eastern Washington and western Bay Counties are equiva- lent to the complete Alum Bluff group to the west. 78 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 79 In support of the above conclusion it can be pointed out that a well drilled at Gully Pond, Washington County, penetrated 26 feet of bluish-green, sandy, shell marl carrying a Chipola fauna di- rectly beneath beds of the Cancellaria zone of the Choctawhatchee formation. On the other hand the Sheffield well in central Wash- ington County penetrated 15 feet of Shoal River sediment overlying 58 feet of Chipola sediment, and underlying the Arca zone of the Choctawhatchee formation. The Alum Bluff group grades northward from Gully Pond into progressively more shallow water deposits. In the vicinity of central Washington County it is represented by locally indurated, greenish- gray, bentonitic (?) silts. This siltstone faces of the Alum Bluff outcrops chiefly on high hills south of Chipley. Exposures are present on Falling Water Hill Rock Hill, Orange Hill. and probably Oak Hill although none have been found there. Section north of Falling Water Sink along the road in the center of the N/2 SE1/ sec. 21, T. 4 N., R. 13 W. Deposits underlying the 250-320 Foot Surface Feet 3) Covered by sand and pebble float ....---------------......... .... ................... ? 2) Mottled red to gray, argillaceous, coarse, pebbly sand with many gray to red, clay-filled fissures and pellets. Rests very irregularly on the Alum Bluff. Unconformity? ........................... 6.0 Alum Bluff group (elevation 235 feet) 1) Greenish-gray, very argillaceous, bentonitic (?) coarse silt, with layers of greenish, silty clay .................-----............---- .....-..-...-....... 9.7 Total ----..........--- ...... -...... -- --. ......................-..--- ... 15.7 (?) Two-tenths of a mile south of the above section, 20 feet of the greenish-gray silt with slightly more sand, is exposed in a ditch at the left of the road. Elevation, 244 feet. An indurated greenish-gray, siltstone ledge, with mottlings of limonitic silt giving it a checkered appearance, is exposed in the center of the NE1/, sec. 28, T. 4 N., R. 13 W. The ledge has the appearance of having been baked and is cemented by siliceous cement, probably derived from the bentonite (7). This indurated phase also gives the name to Rock Hill, where the following section was measured near the center of sec. 24, T. 4 N., R. 13 W. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Deposits underlying the 250-320 Foot Surface Feet 3) Mottled red to yellow, indurated sands and gravel. Elevation at the top of the bed is 260 feet ............................................................... 22.0 2) Dark brown, coarse, indurated gravel ............................................. 3.2 Alum Bluff group 1) Light, greenish-gray sand and silt with clay pebbles, very in- durated by a siliceous cement ............................................................ 15.4 Total ...................... ........ ....... .. ...... ............................ 41.2 The greenish-gray silt is exposed along the road on Orange Hill in the NE1/4 sec. 2, T. 3 N., R. 13 W. In a water well in the NW corner of the NE1/4 SW1/4 see. 16, T. 3 N., R. 13 W. fifty feet of greenish-gray gravel and sand were penetrated. Projected geologic sections indicate that this is the entire thickness of Alum Bluff sedi- ments in this area. The well bottomed in a dense limestone, pre- sumably of Tampa age. Along the Vernon-Wausau road, approximately midway between the two towns, the greenish-gray bentonitic silts, clays, and sands lie at elevations both lower and higher than deposits assigned to the Alum Bluff group (Shoal River formation), and they are apparently interbedded. At locality W-73 in the center of the SW1i see. 27, T. 3 N., R. 14 W., the following section was measured in a small ravine imme- diately north of the road. Elevation at top of the Tertiary is 144 feet. Locality W-73 Deposits underlying the 30-50 Foot Surface Feet 3) Red and light gray, mottled, argillaceous sand with occasional pebbles at base. Lies above bed 2 along a very irregular contact 7.0 Alum Bluff group 2) Greenish-gray, very argillaceous, micaceous silt, separated by a thin limonitic layer from more sandy beds at the base. A few very scattered fossil molds found, but so poorly preserved as to prevent identification ............................... ...... ..................... 9.6 1) Greenish-gray, highly micaceous, sub-angular quartz and weath- ered white feldspar, medium sand grains in a matrix of green, very argillaceous silt. Grit lenses at intervals. Weathers to a mottled yellow and is stained red by a thin overlying limonite layer .............. ........................ .... .... ..----- ... ............-- ..... ............ 14.3 Total .......... ....................... ... ........ .......... ................. 30.9 The green silt phase is also exposed along the Wausau-Vernon road 6.5 miles east of Vernon in the SW1/4 see. 26, T. 3 N., R. 14 W., at an elevation of 165 feet. Five and four-tenths miles east of Vernon in the SE1/4 see. 27, T. 3 N., R. 14 W., at an elevation of 120 feet, is approximately six 80 GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 81 feet of yellow to gray, very micaceous, pebbly, fine to medium sand. Fossil molds assigned to the Alum Bluff group (Shoal River forma- tion) are abundant. The following section is exposed in the SW'/ SE1/4 see 28, T. 3 N., R. 14 W., 3.9 miles east of Vernon in a road cut. Locality W-15-Elevation 146 feet Alum Bluff group (Shoal River formation) Feet 2) Yellow to gray, very micaceous, coarse, argillaceous sand. Con- tains abundant molds of mollusks, weathered at top .................... 15-20 1) Yellow to gray, very micaceous, blocky, sandy clay, with lenses of the material of bed 2, and grading into bed 2 .......................... 10-15 Total ............................. ...................................................... 25-35 Gardner10 identified the following Shoal River assemblage chiefly from bed 2. Cardium waltonanium Dall Ensis sp. cf. E. directus (Conrad) Spisula sp. Spisula sp. cf. 'S. valhosierr Gardner Turritella sp. (occurs at Whites Creek) The north bank of the road cut at locality W-15 exposes a terrace valley fill of the 60-100 Foot Surface with an old soil zone separat- ing the terrace elastics from the more indurated Alum Bluff sedi- ments below (see photograph, fig. 16). at locality W-15. The two beds are separated by soil zones. Photo taken figure Alluvially filled terrace valley lying upon the Alum Bluff group at locality W-15. The two beds are separated bv soil zones. Photo taken facing north. "Personal communication, April, 1940. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 The following localities, in the vicinity of Norum. Washington County, contain a fauna of Shoal River age. Locality W-12: In road cut on State Road 39 in the SW1/4 NE1/4 sec. 7, T. 2 N., R. 15 W. Locality W-12 Terrace valley fill (30-50 Foot Surface-Elevation 83 feet) Feet 4) Weathered red to yellow argillaceous sand with a 6 inch gravel bed at base ............................................................. ....... ... ...................... 0-7 Alum Bluff group (Shoal River formation) 3) Gray, blocky, thin bedded clay, weathering purple ......................... 3.2 2) Brown to gray, sandy, fossiliferous clay ...------...................................... 3.0 1) Light gray, argillaceous sand, more argillaceous toward base. Pos- sible animal borings at top -..................................................7.4 M maximum thickness ................................. ............................... 20.6 Locality W-13: Located along a road cut on State Road 39 in the SE1/4 SW1/4 sec. 12, T. 2 N., R. 16 W.. Locality W-13 Feet 4) The section is cut by alluviated valleys of variable depths, which are filled by plastics. In general these sediments are fine argil- laceous sands with pebbles at the base. Alum Bluff group (Shoal River formation) 3) Greenish-gray, slightly fossiliferous, blocky clay weathering to shades of red ...... ....................................................................... 2.6 2) Reddish-brown, limonitic, thin-bedded, argillaceous sands and sandy clays ............................................................................. ............ ..................--.... 1.7 1) Red and gray mottled, coarse to fine, argillaceous, very fossili- ferous, micaceous, poorly sorted sand with occasional pebbles. (Road elevation 43 feet) --....------...............................................................................------------------------- 6.0 Total ....---------.......... ............................................................................. 10.3 A boring at the base of this section shows the following lithology. The beds may be fossiliferous. The fossils occur only as molds in these beds, however, and they are not preserved in cuttings. 0-7 Very light gray, mottled by brown, gray, and red, micaceous, argil- laceous fine sand. 7-13 Mottled red to gray, argillaceous, micaceous, coarse sand. 13-13.6 Coarse gravel. 13.6-15 Yellow argillaceous coarse sand and gravel. (Elevation 28 feet). One half mile south on Highway 39, a 25 foot outcrop of weath- ered sand and gravel is exposed at locality W-13A and also in sev- eral road cuts along the highway up to the base of the "Holmes Valley Escarpment." Gardner20 assigned these three outcrops to the Shoal River for- mPersonal communication, April, 1940. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA 83 mation, and identified the following fossils from the basal bed of locality W-13A. Gonus sp. of. O. waltonensis Aldrich* Corbula n. sp. (6 strong ribs)* Corbula waltonensis Gardner* Chione cynmina Gardner Ohione sp. indet.* Ohione trimeris Gardner* Maconza sp. indet. Panope sp. cf. P. parawhitfieldi Gardner Phacoides sp. cf. P. paranodonta Gardner W. T. Sheffield's well in the NE1/ SE1/4 see. 16, T. 2 N., R. 15 W. penetrated 15 feet of Shoal River formation, apparently an oyster and pecten reef, and 58 feet of the underlying Chipola for- mation. The Shoal River-Chipola contact has an elevation of 78 feet in this well. The Shoal River outcrops at W-12, W-13, and W-13A project well below the top of the Chipola formation in this well (see fig. 15). The Shoal River fauna of these localities therefore prob- ably pinches out west of the well, or the two faunas merge laterally. No surface evidence of faulting or slumping is present in the region. Southward and down dip, fresh exposures of the Chipola forma- tion occur along Holmes Creek and Choctawhatchee River at eleva- tions near those of the outcrops of the Shoal River formation at localities W-12 and W-13. This evidence indicates that the Chipola and Shoal River faunas of this area were contemporaneous facies of deposition. Locality W-60: On Holmes Creek 200 yards up a small ravine in the NE1/4 sec. 28, T. 2 N., R. 16 W. The elevation is 56 feet at the top of the Tertiary. Locality W-60 Deposits underlying the 10-20 Foot Surface Feet 6) Sand and pebble wash ....--..--. .....-...- .. ...-... ..------......... ................. 10.2 5) Covered ..................................................... ......-...... .... ... .......... ....... 30.5 Alum Bluff group (Chipola formation) 4) Greenish-blue, micaceous, abundantly fossiliferous sandy marl containing many carbonaceous plant remains (sample W-60 no. 1) 3.3 3) Greenish-blue, sandy clay with fossil molds and carbonaceous plant remains (sample W -60 no. 2) ...................................................... 0. 2) Greenish-blue, micaceous, sandy marl, with fossil molds and car- bonaceous plant remains (sample W-60 no. 3) ............................. 2.1 1) Covered to H.olmes Cree.k ............ ........................................................ 14.5 1)Covered.to Holmes ----------- ----------------1 Total....................... .... ............................. ...................... 61.5. Locality W-60A: 200 yards west of W-60, 22 feet above Holmes Creek, and lying above the marl of bed 4 of W-60, is a two foot ex- *Occurs also at locality W-13. FLORIDA GEOLOGICAL. SURVEY-BULLETIN 21 posure of pinkish-gray, very dense, sandy and pebbly limestone. Abundant molds and shells of mollusks are present. Locality W-60B: At the edge of Holmes Creek, 12 feet above water level and immediately west of W-60, there is a ten foot sec- tion of pinkish-gray, dense, highly fossiliferous, sandy and pebbly limestone. Locality W-61: About one-half mile below W-60B, on Holmes Creek, in the SW1I4 sec. 28, T. 2 N., R. 16 W. The approximate ele- vation at the top of the section is 37 feet. Locality W-61 Alum Bluff group (Chipola formation) Feet 3) Badly weathered, white to buff, sandy limestone with oysters and pectens (sample W -61 no.. ) ............................................................ 4.5 2) Buff, calcareous, coquina sand and gravel (sample W-61 no. 2) .... 3.1 1) Unfossiliferous, buff, calcareous sand extending below water level 4.6 Total ...................................................................................................... 12.2 Locality W-62: Dick Peterson's Woodyard Landing on Holmes Creek, in the SW1I/ see. 28, T. 2 N., R. 16 W. This locality has been described by Gardner (Cooke and Mossom, 1929, p. 106), and correlated with beds at Boynton Landing (locality W-11). Other localities of sands and limestones that bear a Chipola fauna in Washington County are: W-9: Located in the SE1/4 SE1/4 see. 5, T. 1 N., R. 16 W. on the east bank of Holmes Creek. Exposed is 26 feet of limestone that is possibly the best locality for collecting Chipola fossils in Wash- ington County. The faunal list from sample W-77, a boring in the unweathered upper part of the section, is included in the micro- faunal checklist (table 7). W-10: Located in the NW/4 NW1/4 see. 9, T. 1 N., R. 16 W. W-11: On Choctawhatchee River at Boynton Landing in the SE1/4 SE1/ sec. 31, T. 2 N., R. 16 W. (Described in Florida 20th Annual Report, p. 106). W-63: Rocky Landing, 11/2 miles west of Red Head in the NE corner of the NW1/4 see. 20, T. 1 N., R. 16 W. A borehole sample (W-76), representing the fresh upper part of this locality, is in- cluded in the micro-faunal checklist. W-66: On the Choctawhatchee escarpment approximately three- quarters of a mile west of Shell Landing in the NE1/4 NE1/4 sec. 31, T. 2 N..R. 16 W. GEOLOGY OF HOLMES AND WASHINGTON COUNTIES, FLORIDA :85 W-71: On Choctawhatchee River at Lassiter Landing in the NE1/4 SE1/4 sec. 13, T. 2 N., R. 17 W. This section is similar to that at locality W-11. W-72: Cuttings from piling borings for the bridge over the Choctawhatchee River in the SW14 NE1/ sec. 36, T. 1 N., R. 17 W. Only two exposures of Alum Bluff sediments are known in Holmes_ County and each of them bears a Shoal River fauna. The Chipola formation may be represented by fine white beach (?) sand which underlies the fossiliferous beds. The geologic section, figures 13 and 15, support this hypothesis. Locality H-9: Flournoy's old mill, in the NE1/ NE1/ sec. 34, T. 3 N., R. 18 W., at an elevation of 164 feet. Gardner (1926, 1928, 1937) has identified many species of mollusks from this locality and placed it in the Shoal River formation. The micro-fauna, however, was determined by Howe (this report) to be either of Choctawhatclice (Arca zone) age or of Shoal River age. The following Eection was measured: Locality H-9 (Se~ Coake, / Vt /i. /7') Deposits underlying the 250-320 Foot Surf ce Feet 4) Sand and pebble wash .............................................................. 75.0? Alum Bluff group (Shoal River formation) 3) Weathered, .brownish-gray, micaceous sand with many fossil molds ..............-............................................................................------------------.....................-----2.1 2) Bluish-gray, compact, micaceous, glauconitio, coquina sand. Shells well preserved. Sample H-9 ...--..... .---------------- ------.----- .0 1) Bluish-gray, argillaceous sand with many fossil molds ................ 1.0 T total .... .. ................................... .. ........... .. ..... 83.1? Locality H-12: (Fig. 17) On Sandy Creek, to the right of a secondary road in the SE1/4 SE1/4 SWI sec. 11, T. 3 N., R. 18 W. The fossils of this locality were identified by Gardner21 to be those of the Shoal River formation. Locality H-12 Deposits underlying the 250-320 Foot Surface Feet 7) Slope covered by reddish sand and quartz pebbles ....................... 25.0 Alum Bluff group (Shoal River formation) 6) Irregularly banded tan to brown, unfossiliferous silt with white silt mottlings ..-- -----------------------............... ...... ............... 12.3 5) Bluish-gray, blocky, micaceous clay, with abundant molds of Busycon sp., Callocardia prosayana Gardner, Cardilni sp., Diplo- donta sp., Dosinia dalli Gardner, Macrocallista walloncUsIis Gard- "Personal communication, April, 1940. FLORIDA GEOLOGICAL SURVEY-BULLETIN 21 Figure 17. Alum Bluff sediments exposed at lcality H-12, in the SE%4 SE% SW4 sec. 11, T. 3 N., R. 18 W. Bed 5 of this locality lies just below the lowest dark band. ner, Metis ? sp. indet., Periplona discus Gardner, Yoldia soror Gardner and carbonaceous plant remains ............................ ........ 8.5 4) Reddish-brown, deeply weathered, blocky, sandy, bentonitic (?) clay with thin grit beds and many molds of Callocardia prosayana Gardner, Oardium waltonianum Dall, OChione ceramota Gardner, Chione trimeris Gardner, Ohlamys sp., Macrocallista waltonensis Gardner, and Panope sp. .......................... ......................... ...................... 1.6 Alum Bluff group (Chipola formation ?) 3) White, limonitic stained, unconsolidated, coarse to fine sand ...... 8.2 2) Greenish-gray, argillaceous, bentonitic (?) silt. Similar in lith- ology to silts of northeastern Washington County (W-73, etc.) .... 2.5 1) Cream to white, limonitic stained, unconsolidated fine dune (?) or beach ( ) sand ..................................................................................... 11.4 Total ................... ....... ............... ......... .................................... 64.5 Thirty-five feet of bed 1 of locality H-12 was penetrated in the well on Walker Hamilton's farm in the SE1/4 sec. 24, T. 3 N., R. 18 W. The base of bed 1 lies at an elevation of 51 feet. When locali- ties H-9, H-12 and this well are projected into a strike section (fig. 13) 130 feet of Alum Bluff is indicated, and the basal white beach (?) sand is approximately 40 feet thick. MOLLUSOAN FAUNAL CHECKLIST OF THE ALUM BLUFF GROUP Symbols:- G Identified at the locality by Dr. Julia Gardner X Identified at the locality by the writer ? Questionably present at the locality ___ co Table 5 MOLLUSCAN FAUNAL CHECKLIST OF THE ALUM BLUFF GROUP Abra lapochi Gardner........... Acteocina incisula (Dall) ............. incisula kolos Gardner........... sphalera Gardner............... Agladrillia empera Gardner...... ... Alectrion grapta Gardner............. waltonensis Gardner............. Aligena lineata Dall................. pustulosa Dall..... .......... sp. Gardner................... Alveinus micculus Gardner........... rotundus Dall.............. Ampullina fscheri Dall.......... Anomia floridana Dall ............... glypta Gardner................. Area accompsa (Dall).............. adamsi (Shuttleworth MS.) ..... gunteri Gardner................ ypomela (Dall)............... initiator Dall.... ......... latidentata (Dall)............ mikkula Gardner........... paratina Dall.......... ... santarosana geratera Gardner .... staminata (Dall).............. SN I 1 N;J~~l Is 010 N3 Ic 'f 0 > > > > '1' '1 0 '0 '0 r~r G G G G G G G G G x x X X .G G ? G G G ' I.. . o . , X X G G G G X G G G G X x x X X X . . .. .. I ~ , I a r. .' a f-1 O 0 N a rl en M r E strebla Gardner ................. waltania Gardner ............... G .. Architectonica granulata (Lamarck)..... .. quadriseriata waltonensis Gardener. G Astarte isosocles Gardner................ sima Gardner ................. G Bittium boiplex Dall ............. .... Calliostoma ceramicum Dall .............. Callocardia prosayana Gardner........ G G prosayana dodona Gardner.......... Cancelaria aldrichi Gardner............. mitrodita Gardner................ paramoorei Gardner. ............. spherotopleura Gardner........... G subtiarophora Gardner............ G waltoniana Gardner............ G Cardita apotegea Gardner ............... Cardium aliculum Dall ............... apateticum Dall var......... .. cestum Dall .................. .. chipolanum Dall ................ .. chipolanum alumen Gardner...... .. compressum Dall ............... propeciliare Dall ............... .. sellardsi Gardner ............... .. sp. 1 ................ ....... . sp. 2 ........................ .. G virile Dall .............. ....... . waltonianum Dall............... G G Chama draconis Dall.................. Chione burnsii Dall............. .. .. ceramota Gardner............... G G P ? .. .. 0 . . . . . .. o . . . . . . . .. . G .. .. X X X X .. G X ,. .. . . . X . . . 0 .. G G, G G G G G G G X . X G G G X X X X X X x X x 3 I I I I I X X I .. x So .0 .. . . ? .. -- .. . .. M O C12 rC 8 O o r 00 cz |
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| 0 | sobekcm_page_globals.constructor | |
| 0 | sobekcm_page_globals.constructor | Application State validated or built |
| 0 | sobekcm_database.verify_item_lookup_object | |
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| 0 | sobekcm_database.verify_item_lookup_object | |
| 0 | sobekcm_page_globals.display_item | Retrieving item or group information |
| 0 | sobekcm_page_globals.get_entire_collection_hierarchy | Retrieving hierarchy information |
| 0 | sobekcm_assistant.get_entire_collection_hierarchy | |
| 0 | cached_data_manager.retrieve_item_aggregation | |
| 0 | cached_data_manager.retrieve_item_aggregation | Found item aggregation on local cache |
| 0 | item_aggregation_builder.get_item_aggregation | Found 'all' item aggregation in cache |
| 0 | system.web.ui.page.page_load (ufdc.page_load) | |
| 0 | sobekcm_page_globals.constructor.on_page_load | |
| 0 | html_echo_mainwriter.add_style_references | Adding style references to HTML |
| 0 | html_echo_mainwriter.add_text_to_page | Reading the text from the file and echoing back to the output stream |
| 52 | html_echo_mainwriter.add_text_to_page | Finished reading and writing the file |