Geology of Florida ( FGS: Bulletin 29 )

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STATE OF FLORIDA
DEPARTMENT OF CONSERVATION
Florida Geological Survey
J. T. HURST, Supervisor of Conservation
HERMAN GUNTER, Director, Geological Survey

GEOLOGICAL BULLETIN No. 29

GEOLOGY OF FLORIDA

By
C. WYTHE COOKE, Ph.D.
SENIOR GEOLOGIST
UNITED STATES GEOLOGICAL SURVEY

Prepared by the
UNITED STATES GEOLOGICAL SURVEY
in cooperation with the
FLORIDA GEOLOGICAL SURVEY

Published for
THE FLORIDA GEOLOGICAL SURVEY
TALLAHASSEE, 1945

SCIENCE ROOM

Manuscript received December 11, 1944

Published September 15, 1945

FLORIDA GROWER PRESS, Tamnpa

~t~-3: ~5"

LETTER OF TRANSMITTAL

HONORABLE J. T. HURST
Supervisor of Conservation
Florida State Board of Conservation

Sir:

I herewith transmit a report entitled GEOLOGY OF FLORIDA, by
Dr. C. Wythe Cooke, Senior Geologist, United States Geological Survey,
Washington, to be published as Geological Bulletin 29.

In 1929 Dr. Cooke was senior author of a report bearing the same title,
Stuart Mossom of the Florida Geological Survey being the junior author.
This report during the years has proven most helpful and is constantly re-
ferred to. The demand for it exhausted the supply numbers of years ago
so that it is now available only in reference libraries.

There has been an ever insistent need and demand for a revision of this
report dealing with the Geology of Florida. Dr. Cooke has met this and the
Florida Geological Survey acknowledges this continued cooperation of the
United States Geological Survey most gratefully. The report is accompanied
by a revised geologic map. Coming at a time when there is so much interest
in Florida's geology I am sure that it will be well received.

Your sympathetic and cordial interest in the work of the Florida Geo-
logical Survey has been an inspiration to me, adding immeasurably to the
pleasures of official services.

Respectfully submitted,

HERMAN GUNTER, Director
Geological Survey

Tallahassee, Florida
February 14, 1945

so784o

CONTENTS

PAGE
Preface- 1
Compositon and structure of the Floridian Plateau 3
Topography 8
Natural divisions 8
Marine terraces 12
Stratigraphy 14
Pre-Cambrian core 21
Pennsylvanian (?) series and older 21
Triassic system 22
Cretaceous system 23
Comanche series 23
Gulf series 24
Tuscaloosa formation 25
Limestone of Eagle Ford age -. 27
Beds of Austin age 27
Beds of Taylor age 28
Lawson limestone 30
Tertiary system 33
Paleocene series 33
Cedar Keys limestone -. 33
Porters Creek formation 35
Eocene series 39
Deposits of Wilcox age 39
Oldsmar limestone 40
Salt Mountain limestone 42
Deposits of Claiborne age 44
Lake City limestone 46
Tallahassee limestone 49
Avon Park limestone 51
Deposits of Jackson pge 53
Ocala limestone .53
Oligocene series 75
Deposits of Vicksburg age 75
MarianAa limestone 75
Byram limestone 81
Deposits of late Oligocene age 86
Suwannee limestone 86
Flint River formation 104
Miocene series 109
Deposits of early Miocene age 111
Tampa limestone 111
Alum Bluff group 136
Hawthorn formation 144
Chipola formation 161
Shoal River formation 167
Deposits of late Miocene age 180

Duplin marl -
Pliocene series -
Deposits of middle Pliocene (Hemphill)
Alachua formation -
Bone Valley formation -
Buckingham marl -
Caloosahatchee marl -
Charlton formation -
Citronelle formation -
Tamiami formation -
Pleistocene series -
Oscillations of sea level -
Deposits of Pleistocene age -
Fort Thompson formation -
Miami oolite -
Key Largo limestone -
Anastasia formation -
Brandywine formation
Coharie formation -
Sunderland formation
Wicomico formation -
Penholoway formation
Talbot formation -
Pamlico sand -
Lake Flirt marl -
Recent series -
Bibliography -
Index- -

age -
-.
-
-
-
-
-
-
-
-
-
-
-

PAGE
- 180
- 197

199
199
203
210
214
227
S 229
238
245
245
- 248
- 249
- 256
262
- 265
- 273
- 276
- 278
- 281
- 286
- 292
- 297
- 311
- 313
- 315
- 327

ILLUSTRATIONS

Plate 1.
Figure 1.
Figure 2.

Figure 3.
Figure 4.

Figure
Figure
Figure
Figure
Figure
Figure
Figure

Geologic map of Florida In pocket
Relief model of part of North America 4
Sketch map of Florida and the adjacent States show-
ing structure of contour lines on top of the
Eocene formations 6
Topographic divisions of Florida 9
Approximate locations of the shore line during the
Paleocene epoch and late Eocene and middle
Oligocene (Marianna) times 37
Fossils from the Ocala limestone 59
Echinoids from the Ocala limestone 60
Troy Spring, Lafayette County 69
Rainbow Spring, northeast of Dunnellon 71
Juniper Spring in eastern Marion County 72
Ocala limestone in quarry at Kendrick 72
Quarry in the Marianna limestone 77

PAGE

Figure 12. Unconformable contact of the Suwannee limestone
and the Hawthorn formation near White
b Springs -
Figure 13. Suwannee River at Branford -
Figure 14. Hypothetical Miocene and Pliocene shore lines -
Figure 15. Fossils from the Tampa limestone -
Figure 16. Suwannee limestone in pit near Brooksville -
Figure 17. Tampa limestone on Six Mile Creek at Orient -
Figure 18. Fossils from the Alum Bluff group -
Figure 19. Fossils from the Alum Bluff group -
Figure 20. Fossils from the Alum Bluff group -
Figure 21. Bluff on Sandy Creek, Holmes County -
Figure 22. Fossils from the Duplin marl -
Figure 23. Fossils from the Duplin marl -
Figure 24. Apalachicola River looking south from Alum Bluff -
Figure 25. Alum Bluff, Apalachicola River -
Figure 26. Rock Spring, Orange County -
Figure 27. Fossils from the Caloosahatchee formation -
Figure 28. Fossils from the Caloosahatchee formation -
Figure 29. Fossils from the Caloosahatchee formation -
Figure 30. Fossils from the Caloosahatchee formation
Figure 31. Caloosahatchee formation on Prairie Creek -
Figure 32. Sand pit in Citronelle formation near Lake Wales
Figure 33. Sand washed free of kaolin, Citronelle formation,
Crossley -
Figure 34. Graphic section of Pliocene and Pleistocene deposits
at Fort Thompson -
Figure 35. Caloosahatchee River at Fort Thompson -
Figure 36. Miami oolite at Miami -
Figure 37. Miami oolite about 20 miles southwest of Miami
Figure 38. Key Largo limestone at Key Largo -
Figure 39. Anastasia formation 4 miles west of Flagler Beach -
Figure 40. Blowing Rocks, north of Jupiter Light -
Figure 41. Anastasia formation at Boca Raton -
Figure 42. Anastasia formation /2 miles north of Jupiter Light
Figure 43. Early Pleistocene shore lines in the Southeastern States
Figure 44. Shore line of the Wicomico sea -
Figure 45. Shore line of the Penholoway sea -
Figure 46. Shore line of the Talbot sea -
Figure 47. Shore line of the Pamlico sea -

PREFACE

This book bears the same title as one written in collabora-
tion with Stuart Mossom and published in 1929 as part of the
Twentieth Annual Report of the Florida Geological Survey.
It contains many paraphrases and verbatim excerpts from
that report without quotation marks or other indications of
origin. References to the original report are chiefly such as
are deemed to be of historical interest. Grateful acknowledg-
ment is made again of the important contributions made by
Mr. Mossom to the original "Geology of Florida," and of the
pleasant association with him.
The years since 1929 have been fruitful in the field of Flor-
idian geology. The subsurface formations have been explored
by many deep borings, made chiefly in the search for petrol-
eum, which have revealed the presence of Paleozoic sediments,
Triassic diabase, and Lower Cretaceous limestones. The faunal
studies of T. Wayland Vaughan and W. Storrs Cole on the
Foraminifera, W. C. Mansfield and Julia Gardner on the Mol-
lusca, and C. Wythe Cooke on the Echinoidea have made bet-
ter known the relationships of the outcropping formations,
have resulted in the recognition of several new stratigraphic
units, and have satisfactorily explained several perplexing
stratigraphic problems. During these same years has come a
better understanding of the isostatic oscillations of sea level,
which have an important bearing on the geologic history of
Florida.

Thanks are due to Dr. Herman Gunter, Director of the
Florida Geological Survey, for unfailing courtesies extended
through many years; to Drs. L. W. Stephenson and John B.
Reeside, Jr., for helpful criticisms; to Mr. and Mrs. Paul L.
Applin for use of a copy of their manuscript on the subsur-
face stratigraphy and structure of Florida; and to Miss M.
Frances Willoughby, Secretary of the Committee on Geo-
logic Names of the United States Geological Survey, for
checking the manuscript for inconsistencies.

C. WYTHE COOKE

Washington, July 5, 1945

GEOLOGY OF FLORIDA

COMPOSITION AND STRUCTURE OF
THE FLORIDIAN PLATEAU
Floridian Plateau is the name applied by Vaughan (1910)
to the great projection of the continent of North America
that separates the deep water of the Atlantic Ocean from the
deep water of the Gulf of Mexico. As thus defined, the Flor-
idian Plateau includes not only the State of Florida but an
equally great or greater area that lies submerged beneath
water less than 50 fathoms (300 feet) deep. (See fig. 1.)
The Plateau terminates at the Florida Keys, where the south-
ern end drops off steeply into the Straits of Florida, which
separate it from Cuba. The Floridian Plateau underlies all of
Florida Bay as well as a broad expanse of the Gulf of Mexico,
whose bottom slopes very gently away from the west coast
of Florida. The eastern edge of the Plateau hugs the shore of
Florida from Palm Beach southward. It extends northward
from Palm Beach through the Atlantic Ocean, diverging
from the shore, which trends north-northwestward. The
median axis of the Plateau trends N. 15 W., passing through
Key West, Bradenton, Sarasota, Cedar Keys, and Madison.
Nearly all of the Peninsula of Florida therefore lies east of
the axis of the Floridian Plateau.
The Floridian Plateau apparently has always formed part
of the continental mass as distinguished from the deep sea, for
the oldest sediments within it were deposited in shallow water.
Its pre-Cambrian core, which has never been reached by the
drill, probably is composed of ancient metamorphic rocks like
those of the Piedmont region of Georgia, with which it is
doubtless continuous beneath the sediments of the Coastal
Plain. A few deep wells have penetrated to rocks-mica
schist, quartzite, and black shale-which appear to be of Pale-
ozoic age. These rocks are intruded by diabase of probable
Triassic age. Upon the Paleozoic rocks lies a thick series of
shallow marine deposits, dominantly limestone, that ranges
in age from Lower Cretaceous to Recent.
There is no evidence that the rocks composing the outer
layers of the Floridian Plateau have ever undergone extensive
deformation. On the contrary, all the rocks now accessible

4 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

FIGURE 1.-View of relief model of part of North America, including the
Floridian Plateau. After COOKE and MOSSOM, 1929, pl. 1.

GEOLOGY OF FLORIDA-FLORIDIAN PLATEAU

lie very nearly horizontal. The distribution of the geologic
formations (see the geologic map, pi. 1) indicates that there
is a broad oval arch trending north-northwestward and cen-
tering in Levy or Marion County. In this arch the Ocala lime-
stone lies at or near the surface throughout a large area ex-
tending from Lafayette and Suwannee Counties in the north
well down into Sumter County in the south and from the
Gulf Coast in Dixie, Levy, and Citrus Counties into Alachua
and Marion Counties in the east. This area measures about
165 miles long by about 60 miles wide. The eroded surface
of the Eocene Ocala (upon which the middle Miocene Haw-
thorn formation was deposited) attains a height of 115 feet
or more above sea level in Marion County.
Where the north-northwestward sloping end of the Ocala
uplift meets the south-southeastward dipping rocks of Geor-
gia, the strata form a broad, flat-bottomed saddle in which
the Ocala limestone lies somewhat deeper than 200 feet below
sea level (Mossom, 1926, structure map facing p. 256). The
seat of this saddle lies in or near Jefferson County. From this
low region the surface of the Ocala limestone rises some 350
feet in about 140 miles, at the average rate of about 2/V feet
to the mile, to the crest of the arch in Marion County. The
average slope from central Marion County to Monroe County,
where the top of the Ocala lies about 1200 feet below sea level
(Cole, 1941, p. 10), appears to be about 5 feet to the mile.
The slope across the arch seems to be intermediate between
these two rates. A generalized structure map of Florida is
shown in figure 2.
The Floridian Plateau north of St. Petersburg has been
tilted downward toward the west. This tilting accounts for
the broad embayment of the west coast, of Florida between
Clearwater and Apalachicola. It has caused the submergence
of the western part of the Ocala uplift, in which the bands of
outcrop of the Ocala, Suwannee, and Tampa limestones are
truncated by the coast line. It also accounts for the absence
along the embayed area of those marine Pliocene formations
that cover nearly all of southern Florida and extend all along
the east coast. To some extent, however, these effects may be
the result of the greater degradation of the part of the Flor-
idian Plateau covered by soluble limestone. It may be signifi-

6 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

cant that the embayed area is bordered throughout by soluble
limestones. Moreover, it is quite likely that the submerged
Miocene formations on the Plateau are composed of more
soluble materials than those formations that crop out on the
land, which contain much sand, for the submerged parts are
farther away from sources of plastic sediment.
Part of the warping that raised the Ocala arch appears to
have taken place before late Eocene (Ocala) time. It was

FIGURE 2.-Sketch map of Florida and adjacent States showing structure by con-
tour lines on top of the Eocene formations. After COOKE and MossoM, 1929, pl. 2.

GEOLOGY OF FLORIDA-FLORIDIAN PLATEAU 7

continued late in Miocene time, for the Hawthorn formation
participated in the movement. The arch was above water in
early Pliocene time, as is shown by the presence of land mam-
mals of that age in the belt east and south and presumably
west of the land area. The tilting that depressed the western
continuation of the belt presumably was contemporaneous
with the crustal movements that deformed many other parts
of the earth at the close of the Pliocene epoch. All the defor-
miation seems to have occurred before the Pleistocene epoch,
for even the oldest Pleistocene shore lines, so far as they have
been traced, remain horizontal.

8 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

TOPOGRAPHY

NATURAL DIVISIONS
Florida has been described (Cooke, 1939c, p. 14) as con-
sisting of five natural topographic divisions, namely, the
Central Highlands, the Tallahassee Hills, the Marianna Low-
lands, the Western Highlands, and the Coastal Lowlands. The
generalized outlines of these divisions are shown in figure 3.
Central Highlands-The Central Highlands extend along
the Peninsula from the Georgia State line between St. Marys
and Withlacoochee Rivers southward nearly to Glades Coun-
ty. This large area is highly diversified. It includes high
swampy plains; hills, the highest in the State; and thousands
of lakes, big and little. Its soils are prevailingly sandy. Much
of the sand was derived from Pleistocene marine terraces, a
good deal from the Miocene Hawthorn formation, and the
Pliocene Citronelle formation. The altitude ranges from less
than 40 feet above sea level in some of the valleys to 325 feet
on the summit of Iron Mountain near Lake Wales, where
rises the beautiful "Singing Tower."
The lakes of the Central Highlands indicate the occurrence
of soluble limestone not far below the surface. The Ocala
limestone, where not too deeply buried, yields a lacy pattern
of innumerable shallow lakes such as Tsala Apopka Lake and
the smaller lakes of Lake County, and it also is marked by
larger, deeper, open lakes like Lake Apopka and Lake Harris.
The Suwannee limestone and limestone of the Hawthorn for-
mation also give rise to lakes, but these do not commonly com-
pare in intricacy and abundance with those underlain by the
Ocala. Many of the lakes have extensive flats or "prairies"
surrounding them.
The most extensive plain in the Central Highlands is the
Sunderland terrace, which occupies several counties in the
northern part of the State and an even larger adjacent area
in Georgia, where it includes the great Okefenokee Swamp.
The terrace is well developed also in Manatee, Hillsborough,
and Polk Counties, and there are smaller remnants of it scat-
tered throughout the Highlands. The Sunderland terrace
was covered by the sea during part of the Pleistocene epoch

GEOLOGY OF FLORIDA-TOPOGRAPHIC DIVISIONS

when the shore line stood approximately 170 feet higher than
present sea level. From an island in the Sunderland sea in the
northwest corner of Putnam County a sandy peninsula and
bar, now called Trail Ridge, extended northward into Geor-
gia and now forms the boundary between the Sunderland
terrace and the Coastal Lowlands.
Tallahassee Hills-A 25-mile-wide strip along the Georgia
line between Withlacoochee River on the east and Apalachi-
cola River on the west-a length of 100 miles-is called the
Tallahassee Hills. The highest part of this region is believed
to be a plain ranging around 300 feet above sea level in the
northwestern part of Gadsden County. It is underlain by red
sand mapped as Citronelle formation. Most of the remainder

FIGURE 3--Topographic divisions of Florida. After COOKE, 1939c, fig. 3.

10 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

consists of rolling hills carved out of the Citronelle and the
underlying clayey sand and fuller's earth of the Hawthorn
formation, which also weather red. This is a fertile farming
region.
Marianna Lowlands-A roughly quadrilateral area in Jack-
son, Holmes, and Washington Counties adjoining Alabama
and Georgia is underlain chiefly by limestone, which, being
soluble and consequently easily degraded, accounts for the
low, generally flat or rolling topography. The Ocala lime-
stone underlies the entire region and crops out in several areas,
the largest north of Marianna, where many springs contribute
clear, cool water to Chipola River. Although the Marianna
limestone occupies a smaller area, it is an important source
of building stone. The largest part of the Marianna Low-
lands is occupied by the Flint River formation and its offshore
equivalent, the Suwannee limestone. The Tampa limestone
forms a narrow band around the southern margin of the area.

Western Highlands-The Western Highlands extend from
Apalachicola River westward to the Perdido, which forms
the western boundary between Florida and Alabama. In the
eastern part of this area they are confined between wide strips
of Marianna Lowlands on the north and Coastal Lowlands on
the south. Farther west, however, they extend from the Ala-
bama line almost to the Gulf, from which they are separated
by a narrow strip of lowlands. The Western Highlands con-
sist of a plateau sloping gently southward. It is underlain for
the most part by the Citronelle formation and high-level
Pleistocene terrace deposits. The plateau is crossed by several
large streams, which flow in deep flat-bottomed valleys. It
is trenched by many small streams, which head in steep-
walled narrow gorges. Some parts of the region are hilly or
rolling.
Coastal Lowlands-The Coastal Lowlands border the en-
tire coast of Florida. They are widest in the south, where
they cover all of the State south of Lake Childs. They are
narrow from Choctawhatchee Bay westward, where they are
only 10 or 12 miles wide at Pensacola. They are narrow also
in Citrus and Hernando Counties. The Coastal Lowlands lie
nearly everywhere less than 100 feet above sea level.

GEOLOGY OF FLORIDA-TOPOGRAPHIC DIVISIONS

The Coastal Lowlands consist for the most part of nearly
level plains. They have so recently been covered by the sea
that great areas of them have suffered little dissection. One
invasion of the sea left successive shore lines at 100, 70, and
42 feet above the present sea level. A later invasion reached
only 25 feet. The marine terraces corresponding to these
Pleistocene shore lines are named Wicomico, Penholoway, Tal-
bot, and Pamlico. The Pamlico terrace, with shore line 25
feet above sea level, is the most extensive plain in Florida. It
covers most of Florida south of latitude 27 as well as broad
strips along both coasts north of that line.
The soil of the Coastal Lowlands is prevailingly light-gray
or drab sand except part of the Everglades and Big Cypress
Swamp, where bare Pliocene sandy limestone or muck and
peat lie at the surface.
A notable feature of the Coastal Lowlands is the Ever-
glade3, a flat, frequently flooded region commonly lower than
16 feet above sea level extending southward from Lake Okee-
chobee in Florida Bay and confined between slightly higher
land on each side. The floor of the Everglades is composed of
Pliocene and Pleistocene limestone and limy sandstone, cov-
ered by sheets or patches of peat and muck derived from
sawgrass.
The Florida Keys comprise a long fringe of low islands that
curve southwestward along the edge of the Straits of Florida
from Biscayne Bay to Key West. Outlying islands such as the
Marquesas, Rebecca Shoal, and the Dry Tortugas might be
included with them. The outer fringe of keys, terminating
at Loggerhead Key, is an emerged coral reef (Key Largo lime-
stone) composed of limestone containing coral heads in their
original position. Most of the keys are long and narrow and
are strung out in a line. Other keys, known as the Pine Islands,
are more irregular in shape and are composed of oolitic lime-
stone (Miami oolite) like that of the mainland. The Mar-
quesas Keys and the Dry Tortugas consist of "coral sand"
heaped up by the waves in the form of atolls on a slightly sub-
merged bank. All of the keys are very low. Probably none
exceed 15 feet above sea level.
Mangrove swamps occupy much of the shallow water be-

12 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

hind the keys. The head of Florida Bay is dotted with them,
and they fringe the mainland from Biscayne Bay as far west
as Cape Romano. Most of the Ten Thousand Islands consist
of mangrove swamps, though some of them are partly sub-
merged sand dunes. Mangroves grow in sheltered tidal waters
as far north as New Smyrna on the east and Cedar Keys on
the west. Their northern limit is determined by climate, for
they cannot endure much freezing weather.

MARINE TERRACES

Some mention has already been made of the Pleistocene
marine terrace plains, of which there are at least seven. These
record oscillations of sea level and are therefore best defined
by reference to the present altitude of the shore line corres-
ponding to each terrace. This is possible because the shore
lines, so far as they have been traced, give no evidence of de-
formation but remain approximately horizontal.

The altitude assigned to each shore line was determined by
the study of innumerable topographic maps of the South-
eastern States. As the contour interval of most of the maps
is 10 feet, the figure chosen may vary a little from the actual
altitude, which is the high-tide mark on the land. This, itself,
is not a level line but varies slightly in altitude according to
the configuration of the coast and because of other factors.
It is, however, much more constant than spot elevations on
the terrace itself, which vary inversely as the depth of the
water on it when it was part of the sea bottom. The error in
the determination of the altitudes of the lower shore lines is
probably not greater than 5 feet. That of the shore lines above
100 feet may be somewhat greater, for the higher lines are
less well preserved and are shown on fewer maps. The present
list was revised in 1931 (Cooke, 1931) and has been repeated-
ly checked since then as new maps have become available.

The altitudes of the shore lines of the seven well-established
terraces are as follows:
Brandywine terrace - 270 feet
Coharie terrace - - 215 feet
Sunderland terrace - 170 feet

GEOLOGY OF FLORIDA-MARINE TERRACES 13

Wicomico terrace -- 100 feet
Penholoway terrace - 70 feet
Talbot terrace - - 42 feet
Pamlico terrace - - 25 feet

These seven marine terraces and the geologic formations
corresponding to them are discussed more fully in the chap-
ter on the Pleistocene series.

14 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

STRATIGRAPHY

GENERAL FEATURES

The rocks underlying Florida range in age from a hypo-
thetical pre-Cambrian core, which has never been penetrated
by the drill, to Recent deposits that are still accumulating.
The oldest formation exposed at the surface is the Avon Park
limestone, of middle Eocene age, which is reported by David
Ericson, of the Florida Geological Survey, to crop out in
Citrus and Levy Counties.
The oldest rocks thus far encountered in bore holes, though
somewhat metamorphosed, are so obviously of plastic origin
that such great antiquity as pre-Cambrian seems unlikely;
one would expect to find pre-Cambrian rocks more highly
altered. They are tentatively assigned to the late Paleozoic
(Pennsylvanian). These rocks are intruded by diabase dikes,
which are assumed to be of Triassic age because of their simi-
larity to the diabase of the Newark group of the Eastern States.
The next younger formation of which there is record is a
limestone. It is assigned to the Comanche because of its simi-
larity to certain limestones of the Comanche series of Texas,
but as the diabase and the limestone were found in different
and widely separated wells, it is quite possible that rocks of
both Triassic and Comanche age are more fully developed in
Florida than one might suppose from the meager evidence
available.
Several deep wells in Florida have passed through strata of
the Gulf series. In the northern part of the State the faces of
the Gulf series are much like those of the supposed contempo-
raneous deposits that crop out farther north, in Alabama and
Georgia. In southern Florida Gulf deposits are less diversified
and consist chiefly of limestone.
The Paleocene series is represented in wells in southern
Florida by limestone and farther north in the State by shale,
both types of rocks suggesting the Midway group of Alabama.
The Eocene series includes formations of Wilcox, Claiborne,
and Jackson age. None are known to appear at the surface

GEOLOGY OF FLORIDA-STRATIGRAPHY

except the Ocala limestone of Jackson age, which crops out
over a wide area, and the Avon Park limestone, which has
recently been found in Levy and Citrus Counties.
Exposures of the older formations of the Oligocene series-
the Marianna limestone and the Byram limestone-are con-
fined to the northern part of the State, but the late Oligocene
Suwannee limestone is known as far south as Hillsborough
County, though a contemporaneous littoral faces, the Flint
River formation, occurs in Florida only in Jackson and
Holmes Counties.
The lower, middle, and upper divisions of the Miocene are
well represented in Florida by the Tampa limestone, the Alum
Bluff group (which includes the Chipola and the Shoal River
formations in western Florida and their equivalent, the Haw-
thorn formation, in the Peninsula), and the Duplin marl. All
crop out at many places, though there are no exposures south
of latitude 27.
The Pliocene deposits of Florida are divided into seven for-
mations, all of which appear to be contemporaneous, repre-
senting merely local lithologic facies. Six are marine or partly
estuarine, the other, a mixture of residual material from older
formations, contains a distinctive fauna of land animals.
Pliocene formations lie close to the surface in nearly all parts
of Florida.
The immediate surface at most places in the State is under-
lain by Pleistocene deposits, of which two principal kinds are
recognized. The most widely distributed is a series of seven
littoral, sublittoral, and estuarine sandy formations corres-
ponding to seven different stages of sea level. These are dis-
tinguishable primarily by their topographic relations, those
underlying the higher terraces being older than the lower ones.
The other kind, which underlies the east coast and the south-
ern part of the State, is divisible into three contemporaneous
marine formations probably of Sangamon interglacial age,
all containing marine shells but differing in facies-one, a
coquina; merging into another, an oolite; the third a coral-
reef limestone. Another Pleistocene deposit, the Fort Thomp-
son formation, includes an alternation of marine shell beds
and fresh-water marls and limestones. It appears to record

16 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

oscillations of sea level corresponding to all the interglacial
and glacial stages from the Nebraskan to the Sangamon, in-
clusive.
The Recent marine deposits include quartz sand, locally
mixed with broken shells, which has drifted along the beaches
as far south as Miami Beach on the Atlantic and Cape Romano
on the Gulf of Mexico, and white limy ooze, which is accumu-
lating in Florida Bay and the adjacent waters. Some of the
fine sand is blown from the beaches into dunes. Chiefly silt
and sand are being deposited in tidal flats and in bars and flood
plains along rivers. Much of this material originates north of
the State line, in Georgia and Alabama. Muck and peat are
the principal deposits in ponds, shallow lakes, and mangrove
swamps. A kind of travertine or caliche locally forms at the
surface in southern Florida. None of these Recent deposits
have been given formation names except the Lake Flirt marl,
which may be partly Recent and partly late Pleistocene.
The formations that are described herein are named in the
accompanying table.

GEOLO(j OF FLORIDA-GEOLOGIC FORMATIONS

GEOLOGIC FORMATIONS IN FLORIDA

Erosion interval. Lake Flirt marl (fresh-water, partly
Recent).

Pamlico sand (littoral, shore line at 25 feet).

Erosion interval.

Talbot formation
(littoral, shore line at
42 feet).

Penholoway formation
(littoral, shore line at
70 feet).

Wicomico formation
(littoral, shore line at
100 feet).

M_
0

41
'i3

*Sl g-

G,
v1

c r

E
SV

0

o

14

Erosion interval. Fresh-water
Fort Thompson formation.

limestone in the

Sunderland formation
S (littoral, shore line at 170 feet).

S Coharie formation
(littoral, shore line at 215 feet).

z
Erosion interval. Fresh-water limestone in the
S Fort Thompson formation.
sri

Brandywine formation
(littoral, shore line at 270 feet).

Erosion interval.

__

Deformation, tilting, and emergence.
Alachua Bone Valley Buckingham
formation formation marl
(terrestrial, (estuarine, (marine).
of Hemphill of Hemphill
age). age).
Erosion interval.

Caloosahatchee
formation
(marine).

Duplin marl (marine, of late Yorktown age).
Erosion interval during early Yorktown time.
W Aluin Bluff group: Shoal River formation (marine).
o W Chipola formation (marine).
S Hawthorn formation (marine).
Tampa limestone (marine, of Anguilla age).
SErosion interval.
Z Suwannee limestone (marine). Flint River formation (littoral, of Antigua age).
U Erosion interval.
S r Byram limestone (marine, of late Vicksburg age).
O Marianna limestone (marine, of early Vicksburg age).
Erosion interval during Red Bluff time.

Ocala limestone (marine, of Jackson age).
Erosion interval.
Avon Park limestone (marine, of Claiborne age).
Tallahassee limestone (marine, of Claiborne age).
Lake City limestone (marine, of Claiborne age).
Erosion interval.
Oldsmar limestone (marine). Salt Mountain limestone (marine, of Wilcox age).

Cedar Keyj limestone (marine). Porters Creek formation (marine, of Midway age).

w
Zv

U
0
-j Cn
&-

Charlton
formation
(estuarine).

Citronelle
formation
(littoral).

Tamiami
formation
(marine).

3z a
P-10'E
< uO
C-i0 C

GEOLOGY OF FLORIDA-GEOLOGIC FORMATIONS

GEOLOGIC FORMATIONS IN FLORIDA (CONT.)

Lawson limestone (marine, of Navarro age).

Limestone and chalk (marine, of Taylor age).

Limestone and shale (marine and littoral, of Austin age).

Erosion interval.

O. Tuscaloosa formation (marine and littoral).

H u Erosion interval.

0 C Limestone (marine).
U U

SErosion interval.
S Diabase (igneous, of Newark age, intrusive into Paleo-
H > zoic system).

O
04 Erosion interval.
Z Cn
0 > Black shale, quartzite, and mica schist (marine or littoral,
probably of Pennsylvanian age).

U

z

S Erosion interval.

C Metamorphic rocks (hypothetical, not reached by drill).

(-

GEOLOGY OF FLORIDA-PRE-CAMBRIAN-PALEOZOIC

PRE-CAMBRIAN CORE
It may be assumed that if one were to drill deep enough
anywhere in Florida he would find a complex mass of folded
and faulted schists, gneisses, and possibly marbles like that
which underlies the Piedmont region in Georgia. These are
the altered and metamorphosed rocks that composed the an-
cient continent of Appalachia, the progenitor of eastern
North America. No well in Florida has yet reached this hypo-
thetical core, and any discussion of it is necessarily specula-
tive. A well in Pierce County, Georgia, some 40 miles north
of Nassau.County, Florida, entered hard, unweathered gran-
ite at a depth of 4340 feet (Schuchert, 1943, p. 453). This
rock, however, may be younger than pre-Cambaj

PENNSYLVANIAN (?) SERIES AND OLDER
Metamorphic rocks were first discovered in Florida (Gun-
ter, 1928) in a boring drilled in 1926 to 1928 by the Ocala
Oil Corporation in sec. 10, T. 16 S., R. 20 E., in Marion Coun-
ty about 3 miles south of York. This hole entered mica schist
at a depth of about 4100 feet, passed through it into white
quartzite somewhere above 4500 feet, and remained in quartz-
ite to a depth of 6180 feet, where drilling was discontinued
(Cooke and Mossom, 1929, p. 44). These rocks are probably
of Paleozoic age. Campbell (1939a, p. 95), however, sug-
gests a correlation with similar rocks in Cuba that Dickerson
and Butt (1935) assigned to the Jurassic. A sample of red
mud taken between 4000 and 4100 feet, above the mica
schist, may represent an oxidized subsoil, or it may be de-
rived from a red shale. A description of an incomplete set of
cuttings from this well was published by Cooke and Mossom
(1929, pp. 44, 45).
The Hilliard Turpentine Company well no. 1, drilled by
the St. Mary's River Oil Corporation from 1936 to 1940, 4
miles northwest of Hilliard (NWI4 NW, SEV4 sec. 19,
T. 4 N., R. 24 E.) penetrated 80 feet of hard black splintery
shale between the depths of 4640 and 4720 feet, then 88 feet
of fine-grained, dense sandstone (4720-4808 feet), then dia-
base to the bottom of the hole at 4824 feet (Campbell, 1939a,
b; Schuchert, 1943, p. 454). The black shale contains ostra-

22 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

codes that R. S. Bassler tentatively identifies as a species of
Amphissites, a genus ranging from Devonian to Permian.
This fossil apparently confirms the Paleozoic age of the shale,
which had been suspected to be Paleozoic because of its ap-
pearance. Cole (1944, pp. 20-21), however, who could find
no authentic fossils in this shale, tentatively assigns the inter-
val from 4640 to 4795 feet to the Triassic.

TRIASSIC SYSTEM
Below the supposed Paleozoic black shale in the well near
Hilliard and presumably intrusive in it is a sill or dike of a
basic igneous rock that J. 0. Fuller (Cole, 1944, pp. 89-94)
identifies as a diabase similar to the diabase of the Triassic
Newark group of the Eastern States. As Triassic intrusives
are widely distributed in the Piedmont region as far south as
Georgia, the reference of the diabase in the Hilliard well to
the Triassic seems justifiable. The drillers log (Cole, 1944,
p. 100) shows diabase between depths of 4821 and 4824 feet,
which was the bottom of the well. Apparently the drill en-
tered it at 4795 feet (Cole, 1944, p. 30).

GEOLOGY OF FLORIDA-COMANCHE SERIES

CRETACEOUS SYSTEM

COMANCHE SERIES
Apparently no rocks of Comanche age were encount-
ered in either the York well or in the Hilliard well, both of
which lie in the northern part of the Peninsula. However, a
thickness of more than 2000 feet of hard limestone similar to
limestones in the Comanche series of Texas alternating with
anhydrite and gypsum was penetrated in the Cory well near
Pinecrest in the Everglades (sec. 6, T. 5 5 S., R. 34 E.). A core
representing the interval between depths of 7944 and 7949
feet consists of hard limestone containing unidentifiable
fragments of a species of Gryphaea, a kind of oyster. These
shells give little clue as to the age, but according to L. W.
Stephenson (Cole, 1941, p. 17) the rock resembles limestone
of the Comanche series. If this rock is of Comanche age, it
cannot be far from the top of the series as represented in this
well, for a core from 7676-7684 feet contains an Upper Cre-
taceous (Eagle Ford age) fossil. Hard limestone, anhydrite,
and gypsum, all common in the Comanche series, continue
to the bottom of )the well at a depth of 10,006 feet. Camp-
bell's (1939b, p. 1714) announcement of the discovery of
Lower Cretaceous deposits in this well was the first published
mention of the presence of the authentic Comanche series
under Florida, though Lower Cretaceous beds had been recog-
nized by E. R. Applin in another well several years earlier
(Campbell, 1939b, p. 1714). Earlier reports (Cushman,
1919) of supposed Lower Cretaceous deposits in Florida re-
ferred to much younger beds that had been misidentified.

The absence of deposits of Comanche age from the north-
ern part of the Peninsula is not surprising, for none are known
beneath the Coastal Plain of Georgia or of any other Atlantic
States, nor do any lie at the surface in Alabama or Mississippi.
The nearest outcrop is in southwestern Arkansas. The land-
ward margin of the Comanche series is overlapped by younger
deposits east of that region, but records of a deep well show
that the Lower Cretaceous Hosston formation underlies
Clarke County, Alabama (Imlay, 1943, p. 1463), with a
thickness of at least 1700 feet. As this well lies about 45 miles
farther north than the Florida State line and less than 30

24 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

miles west of it, and as the regional strike appears to be east-
southeastward, one may infer that the Hosston underlies all
of northwestern Florida also.

GULF SERIES
GENERAL FEATURES
In northwestern Florida rocks of the Gulf series partake
somewhat of the character of contemporaneous deposits ex-
posed farther north in Alabama. As revealed by cuttings
from a well drilled in 1921 for the Chipley Oil Company at
Falling Water, 4 miles south of Chipley, Washington County
(Mossom, 1926, pp. 195-202), they include dark-brown
micaceous sandy clay, gray calcareous clay, gray argillaceous
limestone, and similar deposits. Mossom's description of gray
argillaceous limestone between depths of 2415 and 3465 feet
tallies well with the Selma chalk of Alabama, and Foramini-
fera taken within this interval were regarded by Cushman
(Mossom, 1926, p. 203) as suggestive of that formation.
Ostrea cretacea Morton? (identified by L. W. Stephenson)
at 3615 feet and Ostrea mesenterica Morton and 0. cretacea
Morton (identified by J. J. Galloway) in dark-gray calcare-
ous clay at 3693 feet suggest the Eutaw formation. Drilling
was stopped in dark-brown finely micaceous, sandy clay at a
depth of 4910 feet. It was found impossible to designate defi-
nite boundaries to the formations penetrated by this well,
which was drilled with cable tools. A condensed log with
suggested correlations is given by Semmes (1929, pp. 314-
316).
More specific information about the subsurface conditions
in northwestern Florida is contained in a description by Cole
(1938) of the Granberry well, drilled in 1936, in sec. 15,
T. 5 N., R. 9 W., about 7 miles northeast of Marianna, Jack-
son County. Cole places the top of the Upper Cretaceous at
a depth of 1937 feet and supposes that the hole continues in
the Upper Cretaceous to the bottom, at 5022 feet. He recog-
nizes the Tuscaloosa, Eutaw, and Selma formations in this
well but suggests the possibility that his supposed Tuscaloosa
may really represent the Trinity group of the Comanche
series. The foraminiferal faunas of his Selma are characteris-
tic of the Taylor marl of Texas (Cole, 1938, p. 25).

GEOLOGY OF FLORIDA-GULF SERIES

Beds of the Gulf series in the Peninsula consist for the most
part of limestone. Applin and Applin (1944) recognize
equivalents of the Eagle Ford shale, the Austin chalk, the
Taylor marl, and an upper formation of Navarro age, to
which they give the name Lawson limestone.

TUSCALOOSA FORMATION
GENERAL FEATURES
Name-The Tuscaloosa formation was named from a city
in Alabama. The name dates from 1887, when it was first
used by Smith and Johnson.
Characters-At the outcrop in Alabama and adjacent
States the Tuscaloosa is a littoral and continental formation
consisting chiefly of coarse dirty sand and lenses of clay, some
of which are pure white kaolin. It contains no lime though
it includes a glauconitic member. Recent field work by W. H.
Monroe indicates that it is divisible. The identification as
Tuscaloosa of marine beds in wells far from the outcrop needs
verification, for it is based primarily on their stratigraphic
position below beds of Eutaw age.
Thickness-The thickness of beds assigned by the Applins
to the Tuscaloosa in wells in Florida ranges from 65 feet in
Levy County to 1442 feet in Washington County, where the
base of the formation has not been reached.
Distribution-From the type area in Alabama the outcrop
of the Tuscaloosa formation extends northwestward up the
Mississippi Embayment at least as far as Tennessee and east-
ward to North Carolina, where the formation is overlapped
by younger beds. Marine beds identified with it occupy north-
western and northeastern Florida but appear to be absent from
Marion County. Limestone in southern Florida referred to
the Tuscaloosa by Applin and Applin (1944) is herein de-
scribed under the heading "Deposits of Eagle Ford age."
Stratigraphic relations-At the outcrop the Tuscaloosa
formation lies unconformably on rocks of Paleozoic age or
older, and unconformably under the Eutaw formation or its
equivalent or younger beds. The same relationships may be

26 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

presumed to hold for some distance under cover, for both
unconformities are of wide extent.
Fauna and flora-A few oysters and Brachidontes, a ma-
rine or brackish-water mollusk, have been found at one lo-
cality in Chilton County, Alabama. No other animal remains
have been reported from the outcrop. Some of the clay lenses
contain abundant impressions of leaves.

LOCAL DETAILS
Applin and Applin (1944) record the Tuscaloosa forma-
tion from the following wells in Florida:
Dixie County-Florida Oil & Development Company No. 1
Putnam Lumber Company (sec. 7, T. 11 S., R. 12 E.), depths
3626 to 3741 feet; total depth of well, 4776 feet.
Jackson County-Hammond's No. 1 Granberry well (sec.
15, T. 5 N., R. 9 W.), depths 2803 to 3448 feet; total depth
of well, 5022 feet.
Jefferson County-Southern States Oil Corporation No. 1
Miller and Gossard (sec. 17, T. 2 N., R. 5 E.), depths 3410 to
3838 feet; total depth of well, 3838 feet.
Lake County-Oil Development Company of Florida No. 1
J. Ray Arnold (sec. 17, T. 24 S., R. 25 E.), depths 5322 to
5392; total depth of well, 6120 feet.
Leon County-Central Oil & Gas Company well 3 miles
east of Woodville, depths 3465 to 3755 feet; total depth of
well, 3755 feet.
Levy County-Florida Oil Discovery Company No. 2
Sholtz (Cedar Keys, sec. 9, T. 15 S., R. 13 E.), depths 4170 to
4235 feet; total depth of well, 5266 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 4254 to 4600 feet; total depth of well, 4821 feet.
Wakulla County-Ravlin-Brown No. 1 Phillips (sec. 14,
T. 3 S., R. 1 E.), depths 3672 to 4270 feet; total depth of
well, 5746 feet.
Walton County-Oil City Corporation No. 1 Walton Land

GEOLOGY OF FLORIDA-GULF SERIES

& Timber Company (sec. 12, T. 1 N., R. 19 W.), depths 4133
to 5337 feet; total depth of well, 5337 feet.
Washington County--Chipley Oil Company No. 1 Dekle
(sec. 27, T. 4 N., R. 13 W.), depths 3470? to 4912 feet; total
depth of well, 4912 feet.

LIMESTONE OF EAGLE FORD AGE
A core from a depth of 7676-7684 feet in the Cory No. 1
well of the Peninsular Oil & Refining Company (sec. 6, T. 55
S., R. 34 E.) in Monroe County yielded a fragment of an
Inoceramus that, according to L. W. Stephenson (Cole, 1941,
p. 17), strongly suggests Inoceramus labiatus Schlotheim, a
form of the species restricted to the lower part of the Eagle
Ford shale of Texas. The core consists of speckled limestone
resembling that interbedded with the shale of the Eagle Ford.
The Applins call the limestone between the depths of 7676
and 8168 feet in this well the Tuscaloosa formation, though
the Tuscaloosa at the outcrop represents an entirely different
faces and may be older (L. W. Stephenson, oral communi-
cation).
BEDS OF AUSTIN AGE
GENERAL FEATURES
Hard white limestone penetrated by the Cory well in Mon-
roe County between the depths of 7330 and 7676 feet is cor-
related by the Applins with the Austin chalk of Texas. They
consider it equivalent and continuous with a plastic faces in
northern Florida, which is probably the continuation from
Alabama of the Eutaw formation and the lower part of the
Selma chalk, which overlies the Eutaw. They describe the
plastic faces as composed of gray and greenish-gray marly
shale with fine-grained argillaceous sandstone, sandy mica-
ceous and carbonaceous clay, and some limestone. Lenses of
black to brownish-black speckled shale like that in the lower
part of the Austin chalk are common.
In peninsular Florida the limestone of Austin age ranges
around 250 to 350 feet in thickness. The plastic faces is 150
to 200 feet thick in the neighborhood of Tallahassee and 500
feet thick in northwestern Florida.

28 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

LOCAL DETAILS
The Applins have recognized beds of Austin age in the fol-
lowing additional wells in Florida:
Dixie County-Florida Oil & Development Company No.
1 Putnam Lumber Company (sec. 7, T. 11 S., R. 12 E.),
depths 3365? to 3626 feet; total depth of well, 4776 feet.
Jefferson County-Southern States Oil Corporation No. 1
Miller and Gossard (sec. 17, T. 2 N., R. 5 E.), depths 3268 to
3410 feet; total depth of well, 3838 feet.
Lake County-Oil Development Company of Florida No.
1 J. Ray Arnold (sec. 17, T. 24 S., R. 25 E.), depths 5077 to
5322 feet; total depth of well, 6120 feet.
Leon County-Central Oil & Gas Company well 3 miles
east of Woodville, depths 3180 to about 3410 feet; total
depth of well, 3755 feet.
Levy County-Florida Oil Discovery Company No. 2
Sholtz (Cedar Keys, sec. 9, T. 15 S., R. 13 E.), depths 3740 to
about 4170 feet; total depth of well, 5266 feet.
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T. 13
S., R. 20 E.), depths 3180 to 3520 feet; total depth of well,
4334 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 3900 to 4254 feet; total depth of well, 4821 feet.
Wakulla County-Ravlin-Brown No. 1 Phillips (sec. 14,
T. 3 S., R. 1 E.), depths 3482 to 3672 feet; total depth of
well, 5746 feet.
Walton County-Oil City Corporation No. 1 Walton Land
& Timber Company (sec. 12, T. 1 N., R. 19 W.), depths 3814
to 4133 feet; total depth of well, 5337 feet.
Washington County-Chipley Oil Company No. 1 Dekle
(sec. 27, T. 4 N., R. 13 W.), depths 2870 to 3470? feet; total
depth of well, 4912 feet.

BEDS OF TAYLOR AGE
GENERAL FEATURES
The Selma chalk of Alabama is represented in part by beds

GEOLOGY OF FLORIDA-GULF SERIES

of Taylor age, which underlie the entire State of Florida.
Applin and Applin (1944) have recognized beds of Taylor
age in 12 wells in Florida. In northern and northwestern
Florida they consist of hard gray marl with interbedded lenses
of gray limestone and light-gray, grayish-green, or blue-gray
marly shale, which locally contains carbonaceous matter and
mica. In peninsular Florida they are hard white or cream-
colored chalky limestone. Apparently everywhere they con-
formably overlie beds of Austin age. They are overlain by
beds of Navarro age in northwestern Florida and southeast-
ern Georgia. The contact is presumably unconformable, for
only the lower part of the Taylor is represented in Jefferson
County and in Pierce County, Georgia. They are overlain
unconformably by the Paleocene series in the vicinity of
Tallahassee.
According to the Applins the beds of Taylor age are about
400 feet thick in the central part of peninsular Florida, 600
feet thick in the northeastern part, and more than 1200 feet
thick in Monroe County. Only 200 feet, representing the
lower part of this unit, is present in Jefferson County, where-
as there is more than 700 feet in Wakulla County, the adjoin-
ing county.
The upper part of the beds of Taylor age contain frag-
ments of Inoceramus and several short-ranging species of
Foraminifera, among which the Applins mention Stensi6ina
americana Cushman, Bolivinoides decorate (Jones), and
Anomalina rubiginosa Cushman, var. The lower beds in the
Peninsula carry Planulina texana Cushman, Robulus miinsteri
(Roemer), Globotruncana arca (Cushman), and Globigerina
cretacea d'Orbigny.
LOCAL DETAILS
The Applins have identified beds of Taylor age in the fol-
lowing wells:
Dixie County-Florida Oil & Development Company No.
1 Putnam Lumber Company (sec. 7, T. 11 S., R. 12 E.),
depths 2683 to 3365? feet; total depth of well, 4776 feet.
Jefferson County-Southern States Oil Corporation No. 1
Miller and Gossard (sec. 17, T. 2 N., R. 5 E.), depths 3056 to
3268 feet; total depth of well, 3838 feet.

30 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Lake County-Oil Development Company of Florida No.
1 J. Ray Arnold (South Lake well, sec. 17, T. 24 S., R. 25 E.),
depths 3900 to 5077 feet; total depth of well, 6120 feet.
Leon County-Central Oil & Gas Company well 3 miles
east of Woodville, depths 2675 to about 2900 feet; total depth
of well, 3755 feet.
Levy County-Florida Oil Discovery Company No. 2
Sholtz (Cedar Keys, sec. 9, T. 15 S., R. 13 E.), depths 3239 to
3740 feet; total depth of well, 5266 feet.
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T.
13 S., R. 20 E.), depths 2770 to 3180 feet; total depth of well,
4334 feet.
Monroe County-Peninsular Oil & Refining Company No.
1 Cory (sec. 6, T. 55 S., R. 34 E.), depths 6110 to 7330 feet;
total depth of well, 10,006 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 3280 to 3900 feet; total depth of well, 4821 feet.
Wakulla County-Ravlin-Brown No. 1 Phillips (sec. 14,
T. 3 S., R. 1 E.), depths 2745 to 3482 feet; total depth of
well, 5746 feet.
Walton County-Oil City Corporation No. 1 Walton Land
.& Timber Company (sec. 12, T. 1 N., R. 19 E.), depths 3136
to 3790 feet; total depth of well, 5337 feet.
Washington County-Chipley Oil Company No. 1 Dekle
(sec. 27, T. 4 N., R. 13 W.), depths 2570 to 2870 feet; total
depth of well, 4912 feet.

LAWSON LIMESTONE
GENERAL FEATURES
Name-The name Lawson limestone is applied by Applin
and Applin (1944) to limestone of Navarro age penetrated
between depths of 2235 and 2770 feet in the J. S. Cosden No.
1 Lawson well (sec. 25, T. 13 S., R. 20 E.) in Marion County,
Florida.
Characters-The Lawson limestone is white or cream-col-

GEOLOGY OF FLORIDA-GULF SERIES

ored, calcitic or chalky, locally porous, and includes some
gypsum. It is divisible into two members of which the upper
contains more gypsum than the lower and is impregnated
with calcite to such an extent that most of its fossils are re-
crystallized.
Thickness-The limestone ranges in thickness from about
200 feet to about 800 feet.
Distribution-The Lawson limestone is known only in
wells in the peninsula of Florida. It appears to be absent from
northern Florida from Jefferson County westward, though
it is represented in Walton and Washington Counties by 30
to 50 feet of light-gray chalky marl. Wells in northern Flor-
ida between Nassau County and Jefferson County are not
deep enough to reach it if it is present there.
Stratigraphic relations-The Lawson limestone overlies
beds of Taylor age and underlies the Cedar Keys limestone
(Paleocene). Its upper surface probably became land and
was eroded before the submergence that ushered in the Paleo-
cene epoch. The limestone is correlated with the Navarro
group of Texas. It is possible that the lower member is equiva-
lent to the Ripley formation of Mississippi and Alabama and
the upper member to the Prairie Bluff chalk, both of which
are of Navarro age.
Paleogeography-The Lawson limestone was deposited in
the open ocean, probably far from land. The absence of the
formation from part of northern Florida may be the result
of erosion during the period of emergence that preceded the
Paleocene epoch.
LOCAL DETAILS
The Applins have identified the Lawson limestone in the
following wells:
Dixie County-Florida Oil & Development Company No.
1 Putnam Lumber Company (sec. 7, T. 11 S., R. 12 E.),
depths 1894 to 2683 feet; total depth of well, 4776 feet.
Lake County-Oil Development Company of Florida No.
1 J. Ray Arnold (South Lake well, sec. 17, T. 24 S., R. 25 E.),
depths 3365 to 3900 feet; total depth of well, 6120 feet.

32 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Levy County-Florida Oil Discovery Company No. 2
Sholtz (Cedar Keys, sec. 9, T. 15 S., R. 13 E.), depths 2489
to 3239 feet; total depth of well, 5266 feet,
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T.
13 S., R. 20 E.), depths 2235 to 2770 feet; total depth of well,
4334 feet.
Monroe County-Peninsular Oil & Refining Company No.
1 Cory (sec. 6, T. 55 S., R. 34 E.), depths 5430 to 6110 feet;
total depth of well, 10,006 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 2750 to 3280 feet; total depth of well, 4821 feet.
Polk County-Pioneer Oil Company No. 1 Hecksher-
Yarnell (sec. 28, T. 30 S., R. 25 E.), depths 4300 to 4540 feet
(upper member only) ; total depth of well, 4540 feet.
Sumter County-Dundee Petroleum Company "Bushnell
well" (sec. 36, T. 20 S., R. 22 E.), depths 2940 to 3070 feet;
total depth of well, 3070 feet.

GEOLOGY OF FLORIDA-PALEOCENE SERIES

TERTIARY SYSTEM

PALEOCENE SERIES
GENERAL FEATURES
The strata in the Southeastern States now included in the
Paleocene series comprise the Midway group, which was for-
merly classified as the oldest group of the Eocene series. The
name Paleocene dates back to 1874, when Schimper proposed
it for certain French deposits having a distinctive flora, but
it was not officially adopted for the United States until re-
cently (Cooke, 1939f; 1944, p. 39), although the Midway
group had long been recognized as equivalent to the Paleocene.

CEDAR KEYS LIMESTONE
GENERAL FEATURES
Name-The name Cedar Keys formation was applied by
Cole (1944, p. 27) to limestone known only "in wells in pen-
insular and northern [northeastern] Florida from the first
appearance of the Borelis fauna to the top of the Upper Cre-
taceous." The name is taken from the town of Cedar Keys,
Levy County.
Characters-The formation consists of hard cream-col-
ored to tan limestone.
Thickness-Cole (1944, p. 28) reports a thickness of 570
feet in the Hilliard well and 566 feet in the Cedar Keys well
no. 2. He supposes that it is considerably thicker in the south-
ern part of Florida.
Distribution-The Cedar Keys limestone probably under-
lies all of Florida except the northwestern part, where the
equivalent formation is the Porters Creek clay.
Stratigraphic relations-The formations of the Midway
group at the outcrop are separated from formations above
and below by unconformities. The relations in Florida are
conjectural, but there is little doubt that these unconformi-
ties extend across the Floridian Plateau.
Paleogeography-The Cedar Keys limestone was deposited
in the open ocean. The shore line (fig. 4) extended across

34 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Alabama and Georgia, circling northwestward up the Missis-
sippi Embayment, in and near which the Porters Creek clay
was deposited contemporaneously.
Fauna-Borelis gunteri Cole and B. floridanus Cole, two
related species of Foraminifera, are regarded by Cole as char-
acteristic of the Cedar Keys limestone.

LOCAL DETAILS
The Cedar Keys limestone has been reported from the fol-
lowing wells:
Dade County-East Coast Oil & Gas Company No. 1 War-
wick (sec. 12, T. 55 S., R. 40 E.), depths 3675 to 5432 feet;
total depth of well, 5432 feet. (Applin and Applin, 1944.)
Dixie County-Florida Oil & Development Company No.
1 Putnam Lumber Company (sec. 7, T. 11 S., R. 12 E.),
depths 1561 to 1894 feet; total depth of well, 4776 feet.
(Applin and Applin, 1944.)
Hillsborough County-R. V. Hill's "Oldsmar well" (sec.
18, T. 28 S., R. 17 E.), depths 3090 to 3255 feet; total depth
of well, 3255 feet. (Applin and Applin, 1944.)
Lake County-Oil Development Company of Florida No.
1 J. Ray Arnold (South Lake well, sec. 17, T. 24 S., R. 25 E.),
depths 2570 to 3365 feet; total depth of well, 6120 feet.
(Applin and Applin, 1944.)
Levy County-Florida Oil Discovery Company No. 2
Sholtz (Cedar Keys, sec. 9, T. 15 S., R. 13 E.), depths 2051 to
2489 feet (Applin and Applin, 1944); total depth of well,
5266 feet. Cole (1942) refers the interval from 1965 to 2531
feet to the Cedar Keys limestone. He identified Borelis gun-
teri and B. floridanus in the upper part. The lower part con-
tains some gypsum; no fossils were found in it.
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T.
13 S., R. 20 E.), depths 1730 to 2235 feet; total depth of well,
4334 feet. (Applin and Applin, 1944.)
Monroe County-Peninsular Oil & Refining Company
Cory No. 1 (sec. 6, T. 55 S., R. 34 E.), depths 3310 to 5430
feet; total depth of well, 10,000 feet. (Applin and Applin,

GEOLOGY OF FLORIDA-PALEOCENE SERIES

1944.) Cole (1941, p. 16) reports Borelis sp. at a depth of
3350 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 2215 to 2750 feet (Applin and Applin, 1944) or 2785
feet (Cole, 1944, p. 28); total depth of well, 4821 feet. It
contains Borelis gunteri and B. floridanus.
Polk County-Pioneer Oil Company No. 1 Hecksher-
Yarnell (sec. 28, T. 30 S., R. 25 E.), depths 2630 to 4300 feet;
total depth of well, 4540 feet. (Applin and Applin, 1944.)
Sumter County-Dundee Petroleum Company "Bushnell
well" (sec. 36, T. 20 S., R. 22 E.), depths 2005 to 2940 feet;
total depth of well, 3070 feet. (Applin and Applin, 1944.)

PORTERS CREEK FORMATION
GENERAL FEATURES
Name-The Porters Creek formation was named from a
creek in Hardeman County, Tennessee, by Safford in 1864.
The continuation of this formation in Alabama was later
(1892) called "Sucarnochee" by E. A. Smith, but this syno-
nym seems unnecessary.
Characters and thickness-The Porters Creek at the out-
crop consists of brittle gray to black clay or shale with con-
choidal fracture. It is several hundred feet thick. Accord-
ing to Applin and Applin (1944), wells in northwestern
Florida show that the lower part of the Paleocene series con-
sists of gray to cream-colored marly clay and greenish-gray
highly fossiliferous marl. This is overlain by gray clay, sandy
clay, and less fossiliferous marl.
Distribution-The Porters Creek crops out in a great semi-
circle that extends from western Tennessee through Missis-
sip'pi far into Alabama. Presumably it merges seaward into
the Cedar Keys limestone.
Stratigraphic relations-At the outcrop the Porters Creek
either rests directly and unconformably on strata of the Up-
per Cretaceous series or is separated from those strata by a
thin bed of limestone of the Clayton formation of Paleocene

36 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

age. At the top it merges into the Naheola formation or is
unconformably overlain by younger deposits.
Paleogeography-The Porters Creek formation was laid
down within and near the Mississippi Embayment, into which
an abundant supply of black mud was poured by the tribu-
tary rivers. The approximate location of the shore line is
shown in figure 4.
Fauna-The lower marl carries a microfauna similar to
that of the Tamesi (Velasco) of Mexico (Applin and App-
lin, 1944).
LOCAL DETAILS
The plastic faces of the Paleocene series, presumably the
Porters Creek formation, has been reported from the follow-
ing wells:
Jackson County-Hammond's No. 1 Granberry well (sec.
15, T. 5 N., R. 9 W.), depth 1672 to 1934 feet; total depth
of well, 5022 feet. The Tamesi fauna occupies the interval
from 1761 to 1934 feet. Cores from 1761-1767 and 1878
feet are described as brittle slightly micaceous gray shale
(Applin and Applin, 1944). Cole (1938, p. 23) places the
top of the Midway group at 1726 feet and the bottom at 1937
feet.
Jefferson County-Southern States Oil Corporation No. 1
Miller and Gossard (sec. 17, T. 2 N., R. 5 E.); total depth of
well, 3838 feet. The Applins report the Tamesi fauna be-
tween the depths of approximately 2490 and 3056 feet.
Leon County-Central Oil & Gas Company well 3 miles
east of Woodville; total depth of well, 3755 feet. The App-
lins report the Tamesi fauna between 2235 and 2675 feet.
Wakulla County-Ravlin-Brown No. 1 Phillips (sec. 14,
T. 3 S., R. 1 E.); total depth of well, 5746 feet. The Ta-
mesi fauna occurs between 2665 and 2715 feet (Applin and
Applin, 1944).
Walton County-Oil City Corporation No. 1 Walton Land
& Timber Company (sec. 12, T. 1 N., R. 19 W.), depths
2010 to 3061 feet; total depth of well, 5337 feet. The Tamesi

GEOLOGY OF FLORIDA-PALEOCENE SERIES

FIGURE 4.-Approximate locations of the shore line during the Paleocene epoch
and late Eocene and middle Oligocene (Marianna) times.

38 FLORIDA GEOLOGICAL SURVEY.-BULLETIN TWENTY-NINE

fauna was found between 2400 and 3061 feet (Applin and
Applin, 1944).
Washington County-Chipley Oil Company No. 1 Dekle
(sec. 21, T. 4 N., R. 13 W.); total depth of well, 4912 feet.
The Applins report the Tamesi fauna between depths of 2060
and 2545 feet.

GEOLOGY OF FLORIDA-EOCENE SERIES

EOCENE SERIES
GENERAL FEATURES
As restricted by the elimination of the Midway group
(Paleocene), the Eocene series of the Southern States is di-
visible into three parts. Named in ascending order, they are
commonly called the Wilcox, Claiborne, and Jackson groups.
Each of these groups is separated from the adjacent groups
or from the overlying and underlying series by widespread
unconformities.
In Florida only part of the deposits of Jackson age is ex-
posed to view; the remainder of the Eocene series is deeply
buried. What little information is available about the older
Eocene was obtained from the study of well cuttings.
Throughout the Peninsula, the Eocene series consists dom-
inantly of limestone. Where fossils are present and well
enough preserved for identification, it is usually possible to
recognize the various Eocene formations. But many kinds
of fossils are gregarious, not evenly distributed throughout
contemporaneous beds. Where they are absent or not diag-
nostic one must depend upon other criteria. To some extent
the physical characters of the rock can be used. But this cri-
terion, too, is not reliable, for the very causes that brought
about a segregation of species or their local, spotty distribu-
tion may have produced variations in the rock itself. The
very lack of organic remains from a formation, elsewhere
highly fossiliferous, may give the rock a different texture and
composition.
DEPOSITS OF WILCOX AGE
GENERAL FEATURES
In Alabama the outcropping edges of the Wilcox group
are rather diversified and have been divided into several for-
mations. All consist primarily of plastic materials, though
one (the Bashi formation) contains some lime. Seaward,
under cover, these formations merge into limestone. This
transformation takes place by intertongueing.
The oldest tongue of limestone extends farther inland than
the others. It has been brought to the surface along the Jack-

40' FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

son fault in Clarke County, Alabama, where it has received
the name of Salt Mountain limestone from its most prom-
inent outcrop. Among the distinctive fossils of the Salt
Mountain are two orbitoid Foraminifera, Pseudophragmina
cookei (Vaughan) and Discocyclina blanpiedi Vaughan.
These species are restricted to the Salt Mountain at the out-
crop but seem to have a wider vertical distribution within
the buried limestone of Wilcox age, which has been named
the Oldsmar limestone. Clastic tongues of the Wilcox group
reach southward into part of northwestern Florida, but the
limestone faces occupies most of the State.

OLDSMAR LIMESTONE
GENERAL FEATURES
Name-The name Oldsmar limestone is applied by Applin
and Applin (1944) to limestone of Wilcox age in Florida and
southeastern Georgia. The name is taken from R. V. Hill's
"Oldsmar well" in Hillsborough County, Florida. The Salt
Mountain limestone might appropriately have been expanded
to include all the Oldsmar, which, however, may ultimately
be divided into two or more formations, of which one would
be the Salt Mountain.
Characters-The Oldsmar consists predominantly of lime-
stone, but it contains some gypsum and chert.
Thickness-The Oldsmar is 925 feet thick in the Oldsmar
well and 1200 feet thick in the Peninsular Oil & Refining Com-
pany's no. 1 Cory in Monroe County. Only 445 feet of un-
fossiliferous limestone in Cosden's no. 1 Lawson well in Mar-
ion County is referred to the Oldsmar.
Distribution-The Oldsmar limestone underlies the Pe-
ninsula, the northeastern part of Florida, and the southeast-
ern part of Georgia.
Stratigraphic relations-The top and bottom of the Olds-
mar limestone are probably separated from the adjacent for-
mations by unconformities. At least, that relationship holds
good for the Wilcox group at the outcrop in Alabama and
Georgia. It is possible that there is an unconformity within
the formation corresponding to that which probably separates

GEOLOGY OF FLORIDA-OLDSMAR LIMESTONE

the Nanafalia formation from the Tuscahoma sand in Ala-
bama. In northwest Florida the limestone breaks into tongues,
which interfinger with tongues of clay and sand extending
southward from Alabama. The main body of the Oldsmar ap-
pears to be equivalent to the entire Wilcox group of Alabama.
Paleogeography-The Oldsmar limestone was deposited in
the open sea, far away from land. The boundary between the
area in which limestone was deposited and that in which the
sea bottom was sandy or clayey shifted back and forth from
time to time across northwestern Florida and southern Ala-
bama, producing an interfingering of the limestone with the
plastic sediments.
Fauna-Applin and Applin (1944) recognize four distinct
faunal zones in the Oldsmar limestone. The topmost is char-
acterized by Helicoste'gina gyralis Parker and Grimsdale; the
next by Pseudophragmina cedarkeysensis Cole; the third by
Coskinolina elongata Cole; and the fourth by an unnamed
species of Foraminifera.

LOCAL DETAILS
Applin and Applin (1944) have recognized the Oldsmar
limestone in the following wells:
Broward County-Port Everglades Oil & Gas Company
well 2 miles south of Fort Lauderdale, depths of about 2500
and 3010 feet; total depth of well, 3010 feet.
Columbia County-City well at Lake City (sec. 5, T. 4 S.,
R. 17 E.), depths 1010 to 1012 feet; total depth of well, 1012
feet.
Dade County-East Coast Oil & Gas Company No. 1 War-
wick (sec. 12, T. 55 S., R. 40 E.), depths 2737 to 3675 feet;
total depth of well, 5432 feet.
Miami Oil & Gas Company No. 1 Chevalier (sec. 19, T.
54 S., R. 35 E.), 3720 (first sample) to 3773 feet; total depth
of well, 4560 feet.
Dixie County-Florida Oil & Development Company No.
1 Putnam Lumber Company, depths 1085 to 1561 feet; total
depth of well, 4776 feet.

42 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Hillsborough County-R. V. Hill's "Oldsmar well" (sec.
18, T. 28 S., R. 17 E.), depths 2165 to 3090 feet; total depth
of well, 3255 feet.
SLake County-Oil Development Company of Florida No.
1 J. Ray Arnold (South Lake well, sec. 17, T. 24 S., R. 25 E.),
depths about 2000 to 2570 feet; total depth of well, 6120 feet.
Levy County-Florida Oil Discovery Company No. 2
Sholtz (Cedar Keys, sec. 9, T. 15 S., R. 13 E.), depths 1308 to
2051 feet; total depth of well, 5266 feet.
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T.
13 S., R. 20 E.), depths 1285 to 1730 feet; total depth of well,
4334 feet.
Monroe County-Peninsular Oil & Refining Company No.
1 Cory (sec. 6, T. 55 S., R. 34 E.), depths 2050 to 3310 feet;
total depth of well, 10,006 feet.
Florida East Coast Railroad well at Marathon, Key Vaca,
depths 1920 to 2310 feet; total depth of well, 2310 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 1370 to 2215 feet; total depth of well, 4821 feet.
Polk County-Pioneer Oil Company No. 1 Hecksher-
Yarnell (sec. 28, T. 30 S., R. 25 E.), depths 1960 to 2630
feet; total depth of well, 4540 feet.
St. Johns County-East Coast Hotel Company well at St.
Augustine, depth 1350 feet (last sample) ; total depth of well,
1350 feet.
Sumter County-Dundee Petroleum Company "Bushnell
well" (sec. 36, T. 20 S., R. 22 E.), depths 1430 to 2005 feet;
total depth of well, 3070 feet.

SALT MOUNTAIN LIMESTONE

GENERAL FEATURES
Name-The Salt Mountain limestone was named in 1891
by Langdon from a hill in Clarke County, Alabama, where
it was brought to the surface by the Jackson fault (Cooke,

GEOLOGY OF FLORIDA-SALT MOUNTAIN LIMESTONE

1936a, p. 1163). The outcrops have been thoroughly de-
scribed by Toulmin (1940a).
Characters-At the type locality the Salt Mountain con-
sists of white limestone, which varies somewhat in texture.
Parts are soft and chalky; elsewhere the rock is impregnated
with calcite.
Thickness-According to Toulmin (1940a) the thickness
of the Salt Mountain limestone approximates 90 feet in Clarke
County, Alabama, which is probably not very far.from the
landward margin of the formation. It appears to be about
300 feet thick in Jackson County, Florida.
Distribution-The Salt Mountain limestone underlies
southwestern Alabama and northwestern Florida. It is not
known to crop out anywhere except along the Jackson fault
in Alabama. Elsewhere it is known only from well cuttings.
Stratigraphic relations-According to Blanpied (1938)
the Salt Mountain limestone is equivalent to the Ostrea thirsae
beds of the Nanafalia formation. The limestone presumably
merges northward, toward the shore line of the Nanafalia sea,
into the oyster reefs and other shallow-water deposits of the
Nanafalia.
The Nanafalia formation lies unconformably on deposits
of Midway (Paleocene) age. This unconformity, which is
widespread, probably extends seaward under cover for a con-
siderable distance, possibly throughout the Floridian Plateau.
If so, the Salt Mountain limestone, likewise, is unconformably
on, older beds, either plastic sediments of Midway age or the
Cedar Keys limestone. The relation to overlying beds has not
been determined.
The Salt Mountain limestone appears to be a tongue of 'a
thicker mass of limestone, the Oldsmar limestone, which is be-
lieved to represent the entire Wilcox group. It presumably
lies at the base of the group and is overlain by a tongue of clas-
tic sediments which extends southward and becomes thinner
as the Oldsmar limestone is approached.
Paleogedgraphy-All of Florida and part of Georgia was
submerged during Wilcox time. The Gulf of Mexico then
was merely an embayment of the Atlantic Ocean. The shore
k

44 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

line probably crossed the present Chattahoochee River some-
where between Fort Gaines, Georgia,'and Eufaula, Alabama,
extended across Alabama in a fairly straight line and entered
Mississippi in the northern part of Lauderdale County. This
line paralleled and lay not many miles south of the shore line
of the Paleocene sea.
Fauna-The most conspicuous fossils of the Salt Mountain
limestone at the outcrop in Alabama are two orbitoid Fora-
minifera, Pseudophragmina cookei (Vaughan) and Discocy-
clina blanpiedi Vaughan. These species have not been found
elsewhere in outcropping formations, but they occur at sev-
eral different horizons in the Oldsmar limestone (E. R. App-
lin, oral communication). Toulmin (1941) recognizes 97
species of smaller Foraminifera in the Salt Mountain, and he
(1940b) has described from it two new species of Brachio-
poda, Thecidellina cooperi and Argyrotheca saltmountainen-
sis. It also contains Cidaris splendens Morton and fragments
of other unidentifiable echinoids. Blanpied (1938) reports
that some cores of the Salt Mountain limestone contain Os-
trea thirsae Gabb.
LOCAL DETAILS
Jackson County-Cole (1938) assigns limestone between
the depths of 1406 and 1600 feet in the Granberry well
(SW4 NE4 sec. 15, T. 5 N., R. 9 W.) to the Salt Mountain
limestone. It contains fragments of an orbitoid suggestive of
Pseudophragmina cookei (Vaughan).
Nassau County-Limestone between the depths of 1785
and 1910 feet in the St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company well is classified as Salt Moun-
tain by Cole (1944, p. 27) because of its lithologic charac-
ters and the presence of Pseudophragmina cookei and Disco-
cyclina blanpiedi. It contains also Pseudophragmina cedar-
keysensis Cole. This interval falls within the Oldsmar lime-
stone as identified by Applin and Applio (1944).

DEPOSITS OF CLAIBORNE AGE
GENERAL FEATURES
In Alabama the Claiborne group is divided into two forma-

GEOLOGY OF FLORIDA-EOCENE SERIES

tions, the Tallahatta at the base and the Lisbon above. The
Gosport sand, which was the topmost formation of the orig-
inal Claiborne group, has proved to be of basal Jackson age
and is now classified as Moodys Branch marl (Cooke, 1939a).
The Lisbon is divisible into at least two parts, a lower glau-
conitic part corresponding to the Cane River formation of
Louisiana and an upper calcareous part corresponding to the
Cook Mountain formation of Texas. In Georgia the deposits
of Claiborne age, which are not divided, are called the Mc-
Bean formation (Cooke, 1944, p. 53). Throughout the Coast-
al Plain the outcropping formations of Claiborne age overlie
unconformably deposits of Wilcox age or older formations
and are overlain unconformably and at many places over-
lapped by deposits of Jackson age.

In Florida the deposits of Claiborne age underlie the entire
State, but they are generally buried by younger beds. From
studies of many well cuttings, Applin and Applin (1944)
have been able to recognize two faces, a plastic faces in north-
western Florida and a limestone faces in the northeastern and
peninsular parts of the State. They recognize Cook Mountain
fossils in the plastic faces, which is continuous with the Clai-
borne group of Alabama and presumably is equivalent to the
littoral Tallahatta formation and the Lisbon formation com-
bined. They divide the limestone into three formations, the
Lake City limestone at the base, the Tallahassee limestone
above it, and the Avon Park limestone at the top. Their pro-
files suggest that the Lake City limestone is equivalent to the
plastic faces and that the Tallahassee and the Avon Park are
younger.

The top of the deposits of Claiborne age appears to have
been beveled off before the deposition of the Ocala limestone,
which overlies the plastic faces in northwestern Florida, the
Tallahassee limestone in Gadsden County, and the Avon Park
limestone farther east. This relationship might be explained
as caused by a migration of faces of deposition,. but it may be
the result of subaerial erosion. This latter explanation seems
the more plausible because the deposits of Jackson age every-
where at the outcrop transgressively overlie an eroded surface.

46 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

LAKE CITY LIMESTONE
GENERAL FEATURES
Name-The name Lake City limestone is proposed by App-
lin and Applin (1944) for limestone encountered in wells in
northern and peninsular Florida above the Oldsmar limestone.
The name is derived from the county seat of Columbia
County.
Characters-The Lake City limestone is described as made
up of alternating layers of dark-brown and chalky limestone.
It contains beds of gypsum in the central part of the penin-
sula, the Tallahassee area, and southeastern Georgia. Chert is
especially noticeable in the Tallahassee area.
Thickness-In the northern part of Florida the Lake City
limestone ranges in thickness from 400 to 500 feet, but it is
only 200 to 250 feet thick in the southern part of the
peninsula.
Distribution-As described by Applin and Applin (1944)
the Lake City limestone underlies all of Florida except the
northwestern part, where the limestone merges into a plastic
faces of chalky, glauconitic sand, apparently resembling the
Lisbon formation of Alabama, with which part of it is doubt-
less continuous. The limestone is present also in southeastern
Georgia.
Stratigraphic relations-The Lake City limestone overlies
the Oldsmar limestone, of Wilcox age, and is probably uncon-
formable with it, though this relationship has not been proved.
It is overlain by the Tallahassee limestone or by unfossiliferous
limestone supposed to be equivalent to the Tallahassee. The
Lake City merges westward through highly glauconitic lime-
stone into chalky, glauconitic sand, which presumably is the
offshore equivalent of the Tallahatta and Lisbon formations
of Alabama.
Paleolgeography-During Claiborne time, most of Florida
lay well offshore and received little plastic sediment. The
northwestern part was nearest the land. The shore line ex-
tended across Alabama from the northern part of Choctaw
County to Henry County, thence across Georgia to Rich-
mond County.

GEOLOGY OF FLORIDA-LAKE CITY LIMESTONE

Fauna-Dictyoconus americanus (Cushman) is regarded
by the Applins as a guide fossil of the Lake City limestone. It
is generally accompanied by an abundance of Fabularia
vaughani Cole and Ponton, Discorbis inornatus Cole, and
several other species of small Foraminifera. Discocyclina
(Asterocyclina) monticellensis Cole and Ponton and Lepido-
cyclina (Polylepidina) antillea were found in the Lake City
limestone in Nassau County.

LOCAL DETAILS
The Applins have recognized the Lake City limestone or
the equivalent sandy, glauconitic faces in the following wells:
Brevard County-R. 0. Couch well at Grant, depths 756
to 872 feet; total depth of well, 872 feet.
Broward County-Port Everglades Oil & Gas Company
well, 2 miles south of Fort Lauderdale, depths 2127 to 2500
feet; total depth of well, 3010 feet.
Calhoun County-Calhoun Oil and Gas Company well,
half a mile northwest of Clarksville, depths 1000 to 1320 feet;
total depth of well, 1320 feet. Clastic faces.
Columbia County-City well at Lake City (sec. 5, T. 4 S.,
R. 17 E.), depths 492 to 1010 feet; total depth of well, 1012
feet.
Dade County-East Coast Oil & Gas Company No. 1 War-
wick, depths 2490 to 2737 feet; total depth of well, 5432 feet.
Dixie County-Florida Oil & Development Company No.
1 Putnam Lumber Company (sec. 7, T. 11 S., R. 12 E.),
depths 525 (first sample) to 1085 feet; total depth of well,
4776 feet.
Duval County-City of Jacksonville well at Fourth and
Pearl Streets, depths 805 to 1005 feet; total depth of well,
1005 feet.
Hillsborough County-R. V. Hill's "Oldsmar well" (sec.
18, T. 28 S., R. 17 E.), depths 1910 to 2165 feet; total depth
of well, 3255 feet.
Jackson County-Hammond's No. 1 Granberry well (sec.

48 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

15, T. 5 N., R. 9 W.), depths 200 to 776 feet; total depth of
well, 5022 feet. Clastic faces.
Jefferson County-Southern States Oil Corporation No. 1
Millard and Gossard (sec. 17, T. 2 N., R. 5 E.), depths 1740
to 2223 feet; total depth of well, 3838 feet.
Lake County-Oil Development Company of Florida No.
1 J. Ray Arnold (sec. 17, T. 24 S., R. 25 E.), depths 1010 to
2000 feet (approximately); total depth of well, 6120 feet.
Leon County-Central Florida Oil & Gas Company well
3 miles east of Woodville, depths 1600 to 1995 feet; total
depth of well, 3755 feet.
Levy County-Florida Oil Discovery Company No. 2
Sholtz (sec. 9, T. 15 S., R. 13 E.), depths 811 to 1308 feet;
total depth of well, 5266 feet.
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T.
13 S., R. 20 E.), depths 915 to 1285 feet; total depth of well,
4334 feet.
Monroe County-Peninsular Oil & Refining Company No.
1 Cory (sec. 6, T. 55 S., R. 34 E.), depths 1810 to 2050 feet;
total depth of well, 10,006 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 945 to 1370 feet; total depth of well, 4821 feet.
Rayonier, Inc., well at Fernandina (sec. 60, T. 3 N., R. 28
E.), depths 853 to 1060 feet; total depth of well, 1060 feet.
Polk County-Pioneer Oil Company No. 1 Hecksher-
Yarnell (sec. 28, T. 30 S., R. 25 E.), depths 1540 to 1960 feet;
total depth of well, 4540 feet.
Avon Park Bombing Range (sec. 31, T. 32 S., R. 25 E.),
depths 930 to 1040 feet; total depth of well, 1040 feet.
St. Johns County-East Coast Hotel Company well at St.
Augustine, depths 590 to 1350 feet; total depth of well, 1350
feet.
Sumter County-Dundee Petroleum Company "Bushnell
well" (sec. 26, T. 20 S., R. 22 E.), depths 890 to 1430 feet;
total depth of well, 3070 feet.

GEOLOGY OF FLORIDA-EOCENE SERIES

Suwannee County-City well at Live Oak, depths 475 to
650 feet; total depth of well, 650 feet.
Wakulla County-Bonheur Development Company well
(sec. 16, T. 3 S., R. 1 E.), depths 1750 to 2169 feet; total
depth of well, 2169 feet.
Walton County-Oil City Corporation No. 1 Walton Land
& Timber Company (sec. 12, T. 1 N., R. 19 W.), depths 775
to about 1508 feet; total depth of well, 5337 feet. Clastic
faces.
Washington County-Chipley Oil Company No. 1 Dekle
(sec. 27, T. 4 N., R. 13 W.), depths 375 to 970 feet; total
depth of well, 4912 feet. Clastic faces.

TALLAHASSEE LIMESTONE
GENERAL FEATURES
Name-Applin and Applin (1944) are proposing the name
Tallahassee for limestone found in eight wells near Tallahassee.
Characters-The formation is composed chiefly of cream-
colored and tan crystalline limestone and some softer argil-
laceous limestone. It includes a little tan clay, chert, and
gypsum.
Thickness-The thickness of the Tallahassee limestone
ranges from about 75 feet in wells near its western edge to
650 feet in Jefferson County.
Distribution-The known geographic range of the Talla-
hassee limestone extends from Calhoun County on the west
to Leon and Wakulla Counties on the east. It extends north-
ward into Decatur County, Georgia. Eastward and south-
ward it merges into unfossiliferous limestone, which extends
as far as Nassau County and southward to Polk County.
Stratigraphic relations-The Tallahassee overlies the Lake
City limestone and underlies the Avon Park limestone, which
is overlapped at Quincy by the Ocala limestone. The Talla-
hassee is probably conformable with the Lake City and the
Avon Park, but it is unconformable with the Ocala, if the
relations inferred from the distribution are correct.

50 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

The Tallahassee limestone apparently represents a geologic
horizon not present at the outcrop in western Alabama, where
the Ostrea sellaeformis zone of the Lisbon formation (equiva-
lent to the Wautubbee formation of Mississippi) is overlain
by deposits of Jackson age, which overlap the Tallahassee.
Paleogeography-The Tallahassee limestone was deposited
in the open ocean, probably not far from land. The location
of the shore line is not known. It may have been coincident
with that of the Claiborne group of Alabama, or, more likely,
not so far inland. The presence of clay in the formation, to
which may perhaps be attributed its tan color, suggests a
nearby source.
Fauna-The Tallahassee limestone contains small species of
Foraminifera, many of which appear to be undescribed. As
a whole, its fauna bears some resemblance to that of the Cocoa
sand member of the Yazoo clay of Jackson age, but it includes
some species restricted to the Claiborne group.

LOCAL DETAILS
The Applins (1944) report the Tallahassee limestone in the
following wells in Florida:
Calhoun County-Calhoun Oil & Gas Company well, half
a mile northwest of Clarksville, depths 915 to 1000 feet; total
depth of well, 1320 feet.
Gadsden County-City of Quincy municipal well at wat-
erworks on Bainbridge road, depths 910 to 1395 feet; total
depth of well, 1395 feet.
itr
Jackson County-Florida State Hospital well (sec. 31, T.
4 N., R. 6 W.), depths 400 to unknown; total depth of well,
477 feet.
Jefferson County-Southern States Oil Corporation No. 1
Millard and Gossard (sec. 17, T. 2 N., R. 5 E.), depths 1100
to 1740 feet; total depth of well, 3838 feet.
Leon County-Central Florida Oil & Gas Company well 3
miles east of Woodville, depths 990 to 1600 feet; total depth
of well, 3755 feet.
Wakulla County-Bonheur Development Company well

GEOLOGY OF FLORIDA-EOCENE SERIES

(sec. 16, T. 3 S., R. 1 E.), depths 1200 to 1750 feet; total
depth of well, 2169 feet.

AVON PARK LIMESTONE

GENERAL FEATURES
Name-The name Avon Park limestone, from the Avon
Park Bombing Range wells in Polk County, is applied by App-
lin and Applin (1944) to a formation known only from wells
in Florida and southern Georgia.
Characters-The Avon Park is mainly a cream-colored
challky limestone. It includes some gypsum and chert in
northern Florida.
Thickness-The thickness of the Avon Park ranges from
50 feet or less in northeastern Florida, where only the basal
part is present, to 300 feet in the central part of the Penin-
sula and 650 feet in the southern part.
Distribution-All parts of Florida except the northwest-
ern counties are underlain by the Avon Park limestone. It has
not been found at Lake City nor Live Oak, where it seems to
have been eroded away before the deposition of the Ocala
limestone, nor west of Wakulla County, where it may never
have been deposited.
Stratigraphic relations-The Avon Park comprises the up-
per part of a probably conformable sequence that includes
also the Lake City limestone and the Tallahassee limestone-
all the deposits of Claiborne age in the peninsula. Its upper
surface was eroded before the overlying Ocala limestone was
deposited, and the formation was completely removed from
part of northern Florida. There appear to be no equivalent
deposits at the outcrop in Alabama, at least not at Claiborne,
where the time interval represented by the Avon Park is in-
cluded in the hiatus between the Lisbon formation and the
Moodys Branch marl (Gosport sand), the basal formation of
the Jackson group. It may be equivalent to the Cockfield
formation of Louisiana and Mississippi.
Paleogeography-The Avon Park limestone was deposited
in an open ocean that received little sand or clay. The entire

52 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Floridian Plateau was probably submerged, but the location
of the shore line is unknown.
Fauna-According to the Applins the Avon Park limestone
carries a distinctive and abundant fauna consisting for the
most part of Foraminifera, of which Coskinolina floridana
Cole is the most abundant and persistent species. Dictyoconus
cookei (Moberg) occurs at the top and at the bottom of the
Avon Park as well as in the Oligocene Suwannee limestone in
northern Florida. The small echinoid Peronella dalli (Twitch-
ell) is locally common in the upper part of the Avon Park.
This species was attributed to the Ocala limestone by Cooke
(1942, p. 26) because the type was supposed to have been
found at Archer, where the Ocala limestone is the country
rock. However, the type may have come from a deep well,
for no other individuals have been found at the surface.

LOCAL DETAILS
The Applins studied samples of the Avon Park limestone
from several hundred wells, too many to list in their paper.
The following records are taken from their two general
profiles:
Jefferson County-Southern States Oil Corporation No. 1
Miller and Gossard (sec. 17, T. 2 N., R. 5 E.), depths 880 to
1100 feet; total depth of well, 3838 feet.
Lake County-Oil Development Company of Florida No.
1 J. Ray Arnold (sec. 17, T. 24 S., R. 25 E.), depths 170 to
500 feet; total depth of well, 6120 feet.
Marion County-J. S. Cosden No. 1 Lawson (sec. 25, T. 13
S., R. 20 E.), depths 230 to 360 feet; total depth of well, 4334
feet.
Monroe County-Peninsular Oil & Refining Company No.
1 Cory (sec. 6, T. 55 S., R. 34 E.), depths 1350 to 1810 feet;
total depth of well, 10,006 feet.
Florida East Coast Railway well at Marathon, Key Vaca,
depths 1248 to 1740 feet; total depth of well, 2310 feet.
Nassau County-St. Marys River Oil Corporation No. 1
Hilliard Turpentine Company (sec. 19, T. 4 N., R. 24 E.),
depths 860 to 910 feet; total depth of well, 4821 feet.

GEOLOGY OF FLORIDA-EOCENE SERIES

Polk County-Pioneer Oil Company No. 1 Hecksher-
Yarnell (sec. 28, T. 30 S., R. 25 E.), depths 510 to 800 feet;
total depth of well, 4540 feet.
Wakulla County-Ravlin-Brown No. 1 Phillips (sec. 14,
T. 3 S., R. 1 E.), depths 920 to 1200 feet; total depth of
well, 5746 feet.

DEPOSITS OF JACKSON AGE
OCALA LIMESTONE

GENERAL FEATURES
Name-The Ocala limestone was named from the City of
Ocala, Marion County, in the vicinity of which it has for
many years been extensively quarried. The name was first
formally used by Dall (in Dall and Harris, 1892, p. 103),
who identified it as the Oligocene of Heilprin (which Dall
then considered Eocene). Dall supposed that the Ocala over-
lies the "Orbitoides limestone," which he correlated with the
Oligocene Vicksburg group because of a mistaken identifica-
tion of the orbitoids in it with the common Vicksburg for-
aminifer now called Lepidocyclina mantelli (Morton).
Later, Dall (1903, p. 1554) proposed the general term "Penin-
sular limestone" to replace the name "Orbitoides limestone"
and suggested that the Peninsular might be younger than the
typical Vicksburg and older than the Ocala. Matson and
Clapp (1909) adopted these names, "Peninsular" and "Oca-
la", and proposed the new name "Marianna limestone" for the
limestone of northwestern Florida containing Lepidocyclina
mantelli. For lack of information they were vague as to the
stratigraphic relationships of these three formations, though
they followed Dall in regarding the Ocala as younger than
the Peninsular. They apparently supposed that the Marianna
and the Peninsular were equivalents, though they placed the
Peninsular above the Marianna in a table of formations (Mat-
son and Clapp, 1909, table facing p. 50). Six years later,
Cooke (1915, p. 117) found that much of the Peninsular
limestone is identical with the Ocala limestone; that the Ocala
underlies the Marianna limestone at Marianna, and that the
fauna of the Ocala is overwhelmingly Jackson (upper Eo-
cene) in its affinities.

54 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Characters-The Ocala limestone ranges in color from pure
white through cream-color to yellow. Its texture is com-
monly granular, but parts of it have been converted into hard,
compact rock by the deposition of travertine or calcite in its
interspaces. In some places it consists of a loosely coherent
mass of foraminifers, bryozoans, and other small organisms,
a mass so porous that water can percolate freely through it;
elsewhere it is finer grained and more compact, though still
pervious to water.
The free circulation of water through the Ocala limestone
has facilitated the solution of the rock. Funnel-shaped cavi-
ties, most of them filled with clay and sand and some contain-
ing bones, lead downward from the surface and connect with
ramifying underground passages. The solution of the lime-
stone has at many places been accompanied by the deposition
of silica, either as sheets or as irregular masses of chert (flint)
or as pseudomorphous replacements of shells or granules.
Some of these pseudomorphs preserve with great fidelity the
original form and sculpture of the shell. Such replacements
commonly occur only near the surface, though layers of chert
are encountered at considerable depth in some wells.
In chemical composition as in physical character the Ocala
limestone is remarkably uniform. It consists almost entirely
of carbonate of lime and in places contains as little as four-
tenths of one percent of impurities. The lower part of the
formation as exposed only along the Choctawhatchee River
near the Alabama line is sandy and shaly.
Thickness-The thickness of the Ocala limestone is diffi-
cult to determine because the top of the rock is an eroded,
uneven surface, and the bottom has not been certainly identi-
fied. At Claiborne, Alabama, it is little more than 50 feet
thick (Cooke, 1926a, p. 275); at Albany, Georgia, it is said
to be about 300 feet thick (Prettyman and Cave, 1923, p. 79);
in a well at Live Oak, Suwannee County, whose log is re-
ported by Mossom (1926, p. 222), white limestone contain-
ing Ocala fossils extends from a depth of 110 feet to 300 feet,
where it is succeeded by light cream-colored to brown lime-
stone, presumably the Tallahassee limestone; in a well at An-
thony, Marion County (Mossom, 1926, p. 225), the drill
apparently passed out of the Ocala at a depth of 110 feet,

GEOLOGY OF FLORIDA-OCALA LIMESTONE

where hard blue-gray limestone was encountered. In a well
at Bushnell, Sumter County, Mossom (1926, p. 229) sup-
posed the Ocala to extend to a depth of at least 385 feet, but
Applin and Applin (1944) refer only about 100 feet to the
Ocala limestone, the remainder to the Avon Park limestone.
A well north of Auburndale, Polk County, (Mossom, 1926,
p. 239) entered Ocala limestone at 160 feet; brown limestone
was first encountered in a sample representing the interval
from 448 to 455 feet. Cole (1944, p. 24) assigns a minimum
thickness of 690 feet to the Ocala in the City of Quincy water
well, but the Applins make it only 260 feet, the remainder
being Tallahassee limestone, and Cole (1944, p. 21) found
355 feet of Ocala in the deep well northwest of Hilliard; the
Applins call it 360 feet.
Distribution-The Ocala limestone, which underlies all of
Florida, comes to the surface in two regions. In the peninsula
it extends from Suwannee River at Ellaville, Madison Coun-
ty, southeastward to Lacoochee, Pasco County, and Winter
Garden, Orange County, a length of 165 miles, and from the
Gulf of Mexico between the mouth of Steinhatchee River and
Chassahowitzka Bay eastward to the eastern part of Marion
County, a width of about 60 miles. The limestone is exposed
in many quarries within this tract, though it is commonly
covered by Pleistocene sand or by outliers of the Suwannee
limestone, the Hawthorn formation, or the Alachua forma-
tion. In northwestern Florida the Ocala lies near the surface
in an area extending from Chattahoochee River to the north-
east corner of Walton County, a length of 60 miles, and from
Marianna and Caryville to the Alabama line, a width of 16
miles. In part of this area it is covered by the Flint River for-
mation. This western tract forms part of a much larger re-
gion that includes much of the Flint River basin in Georgia
and the Chattahoochee basin and the valley of Pea River in
Alabama. An exposure of white limestone in a sink at Duncan
Church, Washington County, which was mapped as Ocala
by Cooke and Mossom (1929, p. 61, pl. 2), because of a mis-
taken identification of orbitoid foraminifers, proves to be
Suwannee limestone.
The regions in which the Ocala limestone lies near the sur-
face are generally of low relief except where the limestone is

56 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

covered by outliers of the Hawthorn or Alachua formations,
which are more resistant and make hills. Where the Ocala is
covered by the Flint River formation, the surface is generally
flat or rolling. Because of the solubility of the Ocala much of
the unprotected surface has been reduced nearly to the level
of ground water, and because of the permeability of the rock
this level fluctuates with variations in rainfall. Consequently,
a profusion of lakes have come into existence in the main
region underlain by the Ocala, and many of them are so shal-
low that a slight change in the level of the water causes a
great expansion or contraction in the size of the flooded area.
The principal rivers of this region are the Suwannee and the
Withlacoochee. These streams have few tributaries because
most of the rainfall within their drainage basins enters the
ground and emerges as springs on or near the river banks. The
altitude of the exposed surface of the Ocala in peninsular
Florida ranges from sea level at the Gulf Coast to possibly 150
feet above sea level west of Ocala.
Stratigraphic relations.-In Georgia and Alabama the de-
posits of Jackson age lie unconformably on older beds. The
Jackson sea transgressed across the beveled outcrop from the
middle Eocene Lisbon formation in Alabama to the ancient
crystalline rocks of the Piedmont region in Georgia. That old
pre-Ocala land surface apparently extended into Florida, for
the Ocala transgresses across the beveled surface of the Avon
Park, Tallahassee, and Lake City limestones. The top of the
Ocala limestone was also a land surface before any younger
marine deposits were laid down upon it. The oldest outcrop-
ping rocks on the Ocala are the Marianna limestone of middle
Oligocene age. The hiatus at Marianna apparently represents
Red Bluff (early Oligocene) time of Mississippi and probably
some late Eocene beds that were eroded during that interval.
The hiatus was still longer in the peninsula, for at Ellaville,
Madison County, the Marianna also is absent, and the Ocala
apparently is overlain directly by the Byram limestone. Far-
ther south, in Lafayette and Citrus Counties, the Byram is
missing, and the Suwannee limestone, of late Oligocene age,
is in contact with the Ocala. In Alachua and Marion Coun-
ties the Ocala is commonly overlain by the Hawthorn forma-
tion, of Miocene age.
The Ocala limestone extends westward nearly across Ala-

GEOLOGY OF FLORIDA-OCALA LIMESTONE

bama to Tombigbee River, where it merges into the Yazoo
clay in Clarke and Choctaw Counties (Cooke, 1926, p. 275).
Northward it extends as far as Twiggs and Wilkinson Coun-
ties, Georgia, and it is characteristically developed in wells at
Savannah (Cooke, 1944, p. 68). Its partial equivalent in
South Carolina is the Santee limestone (Cooke, 1936b, p. 40;
1943). The Cooper marl, which overlies the Santee in South
Carolina and the Ocala in Georgia, may be represented by the
upper part of the Ocala in Florida, but definite correlations
have not been established. The Barnwell formation of South
Carolina and Georgia is interpreted as the littoral equivalent
of the Ocala limestone (Cooke, 1944, p. 63).
Paleogeography-The Ocala limestone was laid down in an
open, fairly shallow sea. The shore line (fig. 4) extended
across Alabama in a fairly straight line from Choctaw Coun-
ty to Houston County, then curved northeastward through
Georgia past Macon, to Augusta. Sediments of several kinds
were deposited in the Jackson sea. In Mississippi and western
Alabama clay predominated (Yazoo clay), though the basal
formation, of Jackson age (the Moodys Branch marl), is
sandy. Between Tombigbee River in Alabama and Ocmulgee
River in Georgia and offshore east of that region the sediments
were mainly limestone (Ocala). Near shore east of the Oc-
mulgee calcareous clay, fuller's earth, and sand (Barnwell
formation) were deposited.
Fauna-The most conspicuous elements of the Ocala fauna
are the orbitoid Foraminifera, the Mollusca, and the Echi-
noidea. Some representatives of each of these three retain
their shells intact; others are preserved only as molds.
At some places the Ocala limestone consists almost exclu-
sively of loosely coherent orbitoid Foraminifera. Other zones
are composed chiefly of Operculinoides. Dr. T. Wayland
Vaughan has kindly prepared the following list of the larger
Foraminifera of Georgia and Florida:

LARGER FORAMINIFERA FROM THE OCALA LIMESTONE
By T. W. VAUGHAN
Camerina jacksonensis Gravell and Hanna
moodybranchensis Gravell and Hanna
vanderstoki (M. Rutten and Vermunt)

58 FLORIDA GEOLOGICAL SURVEY--BULLETIN TWENTY-NINE

Operculinoides cookei (Cushman)
curasavicus (M. Rutten and Vermunt)
floridensis (Heilprin)
mariannensis (Vaughan)
ocalanus (Cushman)
vaughani (Cushman)
willcoxi (Heilprin)
Heterostegina ocalana Cushman
Discocyclina (Asterocyclina) americana (Cushman)
chipolensis Vaughan
georgiana (Cushman)
mariannensis (Cushman)
papillata (Cushman)
vaughani (Cushman)
Pseudophragmina (Proporocyclina) citrensis (Vaughan)
flintensis (Cushman)
Lepidocyclina (Lepidocyclina) georgiana Cushman
mortoni Cushman
ocalana Cushman
attenuata Cushman
cookei Cushman
floridana Cushman
pseudocarinata Cushman
pseudomarginata Cushman
tschoppi Thiadens
Lepidocyclina (Nephrolepidina) fragilis Cushman
semmesi Vaughan and Cole

Only a few corals have been found in the Ocala limestone.
A species of Flabellum, probably the common F. wailesii Con-
rad of the Jackson group, is represented by a few molds and
casts.

More species of echinoids have been found in the Ocala
limestone than in any other formation of the Cenozoic era
in the United States, though some species elsewhere were more
gregarious and hence are represented by more numerous in-
dividuals. The following species have been reported from the
Ocala (Cooke, 1941a, 1942) in Florida, Georgia, or Alabama.
A few of them are pictured in figures 5 and 6.

GEOLOGY OF FLORIDA-OCALA LIMESTONE

--------------------------- --------"p-r rn

-__.__ .. 5.a _
5b _7

FIGURE 5.-Fossils from the Ocala limestone. 1, Amusium ocalanum Dall; 2, Oligopygus
wetherbyi de Loriol; 3, Oligopygus haldemani (Conrad); 4, Fibularia vaughari
(Twitchell), X 2; 5, Laganum floridanum Twitchell; 6, Rumphia archerensis (Twitch-
ell); 7, Rumphia eldridgei (Twitchell). After COOKE and MossoM, 1929, pl. 3.

60 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

'
.i '

:,
"
r C ;;I~.~

.~~
~

'""
~f

FIGURE 6.-Echinoids from the Ocala limestone. 1, Eupatagus (Gymnopatagus)
mooreanus Pisbry; 2, Eupatagus (Plagiobrissus) curvus Cooke; 3, Eupatagus (Plagio-
brissus) dixie Cooke; 4, Brissopsis steinhatchee Cooke, X 1 2; 5, Eupatagus (Plagio-
brissus) ocalanus Cooke; 6, Peronella cubae Weisbord, X 1 2. After COOKE, 1942.

GEOLOGY OF FLORIDA-OCALA LIMESTONE

ECHINOIDS FROM THE OCALA LIMESTONE
Psammechinus? ocalanus Cooke
Phymosoma dixie Cooke
?Phymotaxis mansfieldi Cooke
Fibularia vaughani (Twitchell)
Oligopygus wetherbyi de Loriol
floridanus Twitchell
Amblypygus americanus Desor
Periarchus lyelli (Conrad)
Laganum floridanum Twitchell
ocalanum Cooke
Peronella crustuloides (Morton)
cubae Weisbord
Rumphia eldridgei (Twitchell)
S archerensis (Twitchell)
Cassidulus (Cassidulus) Irojanus Cooke
(Paralampas) conradi (Conrad)
lyelli (Conrad)
Eurhodia patelliformis (Bouve)
Schizaster armiger Clark
beckeri Cooke
(Linthia) ocalanus Cooke
Agassizia floridana de Loriol
Brissopsis steinhatchee Cooke
Macropneustes mortoni (Conrad)
Eupatagus (Gymnopatagus) mooreanus Pilsbry
(Plagiobrissus) dixie Cooke
gardnerae Cooke
carolinensis Clark
curvus Cooke
ocalanus Cooke
(Brissopatagus) georgianus Cooke
alabamensis Cooke

Bryozoa are very abundant at certain localities but are less
widely distributed in Florida than in Georgia and Alabama.
More than 80 species of cheilostomatous Bryozoa have been
listed from the Ocala limestone at Ocala, Alachua, and Mari-
anna (Canu and Bassler, 1920).

Mollusks are preserved chiefly as molds or occasionally as
beautifully reproduced siliceous pseudomorphs. The shell
substance of the scallops and oysters is commonly retained.
Amusium ocalanum Dall (fig. 5, no. 1) is a characteristic

62 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

species, and ribbed scallops such as Pecten suwanneensis Dall
and a variable lot commonly identified as P. "perplanus" Mor-
ton are not rare. (The true P. perplanus Morton is a synonym
of P. poulsoni Morton.) Ostrea podagrina Dall has been found
at several places.
The most significant vertebrate known from the Ocala
limestone is the great marine mammal Basilosaurus cetoides
(Owen), fragments of one individual of which were found
near Ocala in 1913 (Cooke, 1915, p. 113; Kellogg, 1936, p.
19). This species is much more common in Alabama and
Mississippi than in Florida, for it seems to have usually stayed
near shore and seldom swam far out to sea. Its presence so far
from land may be an indication that the water on the Floridian
Plateau was shallow and yielded the creature's customary food,
or perhaps the carcass floated out to sea.
Utilization-The Ocala limestone has been extensively
quarried at many places. Because of its uniform texture it is
easier to excavate and crush than the Suwannee limestone,
which tends to be lumpy. Its freedom from grit and its chem-
ical purity make it suitable for any use demanding those qual-
ities, such as the manufacture of cement, and it is much used
for the making of lime. The Ocala is the best road-building
rock available in quantity in the State. It is somewhat softer
than the ideal rock for that purpose, but it binds well and
makes a fairly durable road when surfaced with a suitable
material. Some of the harder parts of the limestone are used
for railroad ballast, and there is a very slight local demand for
it as a building stone. The quantity available is limited only
by the depth to the water table, which is greatest in the up-
lands because of the permeability of the rock.

LOCAL DETAILS
.Alachua County-Most of the exposures of the Ocala
limestone in Alachua County are in the southwestern half.
The limestone is covered by the Hawthorn formation in the
northeastern part and by residual sand and clay referred to
the Alachua formation in the southwest corner. There are
exposures along Santa Fe River near High Springs, in sink
holes and road cuts near Alachua and Gainesville, and in many
phosphate pits in the vicinity of Newberry and Archer. The

GEOLOGY OF FLORIDA-OCALA LIMESTONE

limestone is quarried at a number of places for road metal
or to make lime.
A pit of the Cummer Lumber Company 1 /4 miles south-
east of Newberry shows 20 feet of soft creamy yellow Ocala
limestone containing many foraminifers and casts of mol-
lusks. The Gainesville Lime-Rock Company quarries the
Ocala to a maximum depth of 21 feet. Ten feet of soft, friable
pure limestone is visible in the pit of the Arrendondo Lime
Company 5 /2 miles southwest of Gainesville. There are also
pits near Wilcox, Fanning Springs, and Archer.
At Alachua Sink, 3 /2 miles southeast of Gainesville, 14 feet
of Ocala limestone is overlain unconformably by about 23
feet of Hawthorn formation. The following species have
been collected there:
Foraminifera (identified by T. W. VAUGHAN):
Operculinoides floridensis (Heilprin)
Pseudophragmina (Proporocyclina) flintensis (Cushman)
Lepidocyclina (Lepidocyclina) ocalana Cushman
Bryozoa (identified by R. S. BASSLER):
Schizopodrella viminea (Lonsdale)
Membraniporidra spissimuralis Canu and Bassler
Stamenocella inferavicularia Canu and Bassler
Mollusca (identified by C. W. COOKE):
Ostrea vicksburgensis Conrad
Pecten suwanneensis Dall?
indecisus Dall?
"perplanus" Dall
Annelida:
Tubulostium n. sp.
Echinoidea (identified by C. W. COOKE):
Peronella cubae Weisbord
Citrus County-The Ocala limestone is covered by the
Suwannee limestone in the southeastern part of Citrus Coun-
ty and by the Alachua formation and Pleistocene sand in a
belt west of Tsala Apopka Lake. A wave-cut terrace on which
some beach sand remains borders the Gulf Coast and abuts
against a steep cliff in which the Ocala limestone is exposed
in the lower part and the Suwannee limestone in the upper
part. The Crystal River Rock Company works these lime-
stones to a depth of 121 feet below the top of the cliff in secs.

64 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

1 and 6, T. 19 S., Rs. 17 and 18 E., 5 miles southeast of Crystal
River. Mansfield (1939a) estimates that the contact of the
Suwannee on the Ocala stands as much as 70 feet above the
floor of the quarry at some places. The Ocala in this quarry
has yielded the following species of echinoids:
Oligopygus wetherbyi de Loriol
Laganum ocalanum Cooke
Peronella cubae Weisbord
Rumphia eldridgei (Twitchell)
Schizaster armiger Clark
(Linthia) ocalanus Cooke
Agassizia floridana de Loriol
The Ocala is exposed also in several quarries and old phos-
phate pits in the eastern part of the county between Istachatta
and Holder, particularly in the neighborhood of Inverness.
There are also many patches of the rock in and around Tsala
Apopka Lake.
A drainage ditch on Florida Highway 15, 5.2 miles north-
west of Crystal River, cuts into hard white Ocala limestone
containing Periarchus lyelli (Conrad). The springs forming
the heads of Crystal River, Homosassa River, and Chassahow-
itzka River rise through Ocala or Avon Park limestone.
About 33 feet of white Ocala limestone, most of it soft and
powdery, is exposed in the Miley rock pit in sec. 36, T. 20 S.,
R. 18 E. A harder zone near the top contains Ostrea poda-
grina Dall, Pccten alpha Dall?, Peronella cubae Weisbord?,
Rumphia eldridgei (Twitchell), and other fossils. The Ocala
there is overlain by about 18 feet of white limestone, presum-
ably Suwannee though it resembles the Byram at Ellaville,
containing Clypeaster rogersi (Morton) and Cassidulus
gouldii (Bouve).
At Red Level, north of Crystal River, there is a pit about
25 feet deep in cream-colored soft, powdery magnesian lime-
stone analyzing about 36 to 39 percent MgCO3. The rock
is probably an altered faces of the Ocala limestone.
Dixie County-A large borrow pit in the Ocala limestone
at Steinhatchee River north of U. S. Highway 19 has yielded
the following species of echinoids:

GEOLOGY OF FLORIDA--OCALA LIMESTONE

Oligopygus wetherbyi de Loriol
Peronella cubae Weisbord
Rumphia eldridgei (Twitchell)
Cassidulus trojanus Cooke
(Paralampas) carolinensis Twitchell
Schizaster armiger Clark
Agassizia floridana de Loriol
Two miles below Highway 19 Steinhatchee River falls over
a ledge of dolomitic limestone, apparently altered Ocala, con-
taining molds of small nummulitic foraminifers and Pecten
"perplanus".
A canal near the mouth of Steinhatchee River near Jena
cuts into the Ocala limestone. There are many other shallow
excavations in the Ocala within Dixie County. The surface
of the Ocala in a quarry near Highway 19, 6.2 miles west of
Suwannee River near Oldtown, is closely pitted with large
solution chimneys. Amusium ocalanum Dall and orbitoid
foraminifers were noted there in the Ocala, which is overlain
by 3 or 4 feet of sand.
Gilchrist County-Ocala limestone probably lies not far
below the surface everywhere in Gilchrist County except in
the eastern part, where it is overlain by the phosphate-bearing
Alachua formation. Pleistocene sand probably covers the
rock in the eastern part. No details are available.
Holmes County-Although the Ocala limestone lies not
far below the surface everywhere in Holmes County, except
the southwestern quarter, exposures of the rock are not num-
erous, much of it being covered by the Flint River formation.
Vernon (1942), who has made a detailed study of the county,
maps the Ocala along Choctawhatchee River and Pittman
Creek in the north-central part and along Wrights Creek and
Ten Mile Creek. He also indicates a patch along Choctaw-
hatchee River about one mile above the Washington County
line.
The basal part of the Ocala limestone as exposed along the
Choctawhatchee from Geneva, Alabama, to the middle of
sec. 34, T. 6 N., R. 16 W., 1 /2 miles below the State line, dif-
fers from the typical faces in that it consists of dirty-gray,
pepper-and-salt, sandy marl containing glauconite and mica

66 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

and many molds of small bivalve mollusks. In Alabama the
marl forms steep banks 10 feet high, but in Florida it is finer,
softer, and more shaly and extended only 4 feet above the
river level when visited in June 1921.
Yellow limestone containing large curved orbitoid fora-
minifers crop out below water level in Blue Spring, which
rises west of the Choctawhatchee, probably in sec. 12, T. 5 N.,
R. 17 W. This rock resembles the Suwannee limestone but is
suspected to be Ocala because of its geographic location.
Ocala limestone containing bryozoans, a large thick orbit-
oid foraminifer, Lyria? sp., and other fossils extends to a
height of 4 feet above a mill stream (Little Gum Creek?) in
the NW/4 SE/4 sec. 26, T. 5 N., R. 16 W. Chert of the Ocala
was noted also in the woods in the E of section 26. Dr. Rob-
ert 0. Vernon kindly guided the writer to both of these ex-
posures. Vernon (1942, pp. 53-54) refers this limestone to
the lower part of the Marianna because of the foraminifers
and ostracodes that it contains but states that F. Stearns Mac-
Neil found Amusium ocalanum, a sure indicator of the Ocala,
in it. Both formations may be represented there.
Typical Ocala limestone containing Asterocyclina sp. and
many specimens of Amusium ocalanum was seen in 1921 at a
turpentine landing on the east side of Choctawhatchee River
about a mile above the mouth of Wrights Creek. Similar rock
was struck in excavations for a bridge at Caryville.

Jackson County-Exposures of the Ocala limestone are
fairly common in the north half of Jackson County except
at the eastern and western ends, where the Ocala is covered
by an overlap of the Flint River formation. The best-known
exposures are at and near the highway bridge at Marianna,
where the Ocala rises about 10 feet above water level in
Chipola River and is overlain by the Marianna limestone.
(See section, p. 80.) The rock there is a granular mass of
loosely cemented organic remains, including many foramini-
fers and bryozoans. It appears to represent the same zone as
that exposed along Flint River at Bainbridge, Georgia (Cooke,
1915, p. 110; 1917, pp. 111-112; 1944, p. 72). Canu and
Bassler (1920, pp. 20-33) list 56 species of Bryozoa from the

GEOLOGY OF FLORIDA--OCALA LIMESTONE

Ocala at Marianna, and T. W. Vaughan has identified the fol-
lowing species of larger Foraminifera:
Operculinoides ocalanus (Cushman)
mariannensis (Vaughan)
Heterostegina ocalana Cushman
Discocyclina (Asterocyclina) americana (Cushman)?
georgiana (Cushman)
mariannensis (Cushman)
papillata (Cushman)
vaughani (Cushman) ?
Pseudophragmina (Proporocyclina) citrensis (Vaughan)
Lepidocyclina (Lepidocyclina) georgiana Cushman
Lepidocyclina (Nephrolepidina) fragilis Cushman

The Florida Caverns, about 3 miles north of Marianna, are
in the Ocala limestone. The large echinoid Macropneustes
mortoni (Conrad) occurs there. This is the only known oc-
currence of the species in Florida, though it is common in the
Ocala in Georgia and Alabama (Cooke, 1942, p. 51).

Blue Springs, 6 miles east-northeast of Marianna, probably
rises from the Ocala limestone, though the Ocala is riot known
to be exposed there. The rock at the surface is the Marianna
limestone. The spring issues from a cavern 10 or 15 feet be-
low the water level.
A quarry east of U. S. Highway 231 in the E, sec. 13,
T. 6 N., R. 12 W., about 2 miles south-southeast of Campbell-
ton, exposes Ocala limestone containing Amusium ocalanum,
Oligopygus sp. (probably 0. haldemani), and other fossils.
It is overlain by somewhat harder limestone containing many
large thick Lepidocyclina sp., Pecten poulsoni, and Clypeaster
sp. (probably C. rogersi), presumably an unmapped outlier
of the lower part of the Marianna limestone. The contact is
a sharp nearly horizontal line, probably marking a discon-
formity.

Ocala limestone containing foraminifers, bryozoans, and
Amusium o'calanum was noted in 1921 near the sink of Car-
ters Mill Creek in sec. 20, T. 5 N., R. 11 W., about 3 /2 miles
north-northwest of Marianna. About 27 feet of hard white
limestone with softer patches was exposed, but some of it may
not be Ocala.

68 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Lafayette County-The western part of Lafayette County
is covered by the Suwannee limestone, but elsewhere the
Ocala lies near the surface. The best natural exposures of the
Ocala are in the banks of Suwannee River, which forms the
eastern boundary of the county. Twelve feet of limestone is
visible at Troy Spring (fig. 7), 10 feet at Fort McComb, 6
feet at Dowling Park, and about the same amount at many
other places along the river. Much of the rock on the river
is case-hardened and weathered into tubular cavities. It con-
tains several species of orbitoid Foraminifera, including Lepi-
docyclina ocalana, L. pseudomarginata, and L. floridana; Os-
trea podagrina, Pecten suwanneensis, Rumphia eldridgei, and
many other fossils.
A large road-metal quarry north of Florida Highway 5A,
5.2 miles northwest of Mayo, shows white and buff-colored
friable porous limestone. This pit has yielded foraminifers
and bryozoans as well as the following mollusks and echinoids:
Ostrea podagrina Dall
Pecten suwanneensis Dall
sp.
Pinna quadrata Dall?
Tubtlostium n. sp.
Oligopygus wetherbyi de Loriol
Rumphia eldridgei (Twitchell)
Cassidulus trojanus Cooke
Schizaster armiger Clark
Eupatagus dixie Cooke
ocalanus Cooke

The Taylor County rock pit in Lafayette County 4.8 miles
northwest of Mayo on Florida Highway 5A uses Ocala lime-
stone. Lumps of silicified Suwannee limestone are nearby.
Lake County-Most of the lakes in Lake County were
probably formed by solution of the Ocala limestone, which
in most places is covered by deep sand referred to the Pliocene
Citronelle formation.
Levy County-The Ocala limestone underlies all of Levy
County except, possibly, a strip bordering the coast and ex-
tending into the Gulf Hammock, where hard sandstone con-
taining Chione cancellata and, therefore, of Pleistocene or

GEOLOGY OF FLORIDA-OCALA LIMESTONE

Pliocene age, conceals the bedrock. The Ocala is generally
covered by Pleistocene sand except in the eastern part, where
it is overlain by the Alachua formation.
As Levy County occupies the central part of the Ocala Up-
lift, which extends westward beneath the Gulf of Mexico,
and as it is topographically lower than the counties adjoining
it on the east, the outcrops of the Ocala limestone presumably
are lower stratigraphically than those in the neighboring re-
gions. The occurrence near Inglis of Periarchus lyelli, a very
abundant echinoid in the basal Jackson Moodys Branch marl
in Alabama and Mississippi and in the Tivola tongue of the
Ocala limestone in Georgia suggests that the bed containing
it lies not far above the base of the Ocala.

FIGURE 7.-Troy Spring, Lafayette County, Suwannee River in the background.
After COOKE, 1939c, fig. 52.

Soft cream-colored granular Ocala limestone underlies the
bog-iron ore on the old Studsill place about 3 miles northwest
of Levyville. It is exposed in natural wells. Yellowish or
cream-colored limestone containing Lepidocyclina ocalana
floridana, a few bryozoans, and indeterminable mollusks, rises
6 feet above water level in Manatee Spring, which bursts up
from a deep hole in the Ocala limestone near Suwannee River.

70 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Ocala limestone is exposed in Willow Sink and several other
sinks in the SE4 sec. 34, T. 11 S., R 14 E., 1 / or 2 miles west
of Chiefland. It is white or cream-colored and contains sev-
eral varieties of Lepidocyclina ocalana Cushman, Peronella
crustuloides (Morton), and Pecten sp. The rock rises about
13 feet above water level and extends at least 20 feet below.
The rock exposed at Wekiva Spring, 12 miles south of Bron-
son, is cream-colored or yellowish compact to granular lime-
stone composed chiefly of small foraminifers. It rises 3 or 4
feet above water and extends 23 feet below water in the spring.
A sample taken about 4 feet below water level does not differ
materially from that above it.
Many pits for road metal have been opened in Levy Coun-
ty. The pit of the Florida Shell Rock Company, 2 miles north
of Williston, shows 38 feet of pure soft limestone that seems
somewhat more compact and less friable than that found else-
where in the formation. A pit near the mouth of Withlacoo-
chee River between Inglis and Yankeetown is about 5 feet
deep. It has yielded the echinoids Periarchus lyelli (Conrad),
Eupatagus mooreanus Pilsbry, and Agassizia floridana de
Loriol.
Madison County-Exposures of the Ocala limestone in
Madison County are confined to the banks of Suwannee River
and are visible only at low water. The Ocala there is overlain
by a thin bed of limestone that is supposed to be of Byram
(middle Oligocene) age. The Byram is overlain bythe Su-
wannee limestone.
Marion County-Marion County is the type area of the
Ocala limestone, which takes its name from the county seat.
The limestone lies near the surface throughout a large part of
the county but is covered by deep sand of the Citronelle for-
mation in the eastern part, by the residual sand and hard-rock
phosphate of the Alachua formation in the western part, and
by outliers of the Hawthorn formation in the central part.
The Ocala limestone in Marion County is soft, pure, creamy
white, granular, and porous. Most of it is so soft that it can
be crumbled in the hand, but harder masses are found in all
pits. The surface of the rock is deeply pitted with solution
channels and clay-filled holes, some as much as 25 feet deep.

GEOLOGY OF FLORIDA-OCALA LIMESTONE

The rock is extensively utilized in the manufacture of lime
or as road metal. These industries center in Ocala, the site of
the oldest lime pits in the State.
There are many lime pits in Marion County (see fig. 10),
and they present little variation. The pits are deeper than
those in other parts of the State, because the top of the rock
is higher and the water table lies farther below the surface.
Near Ocala the top of the limestone stands generally around
110 feet above sea level, and the water table between 40 and
50 feet above sea level (Stringfield, 1936, p. 151). Therefore,
pits as deep as 60 or 70 feet may remain dry.

FIGURE 8.-Rainbow Spring, northeast of Dunnellon. After COOKE, 1939, fig. 44.

Silver Springs, near Ocala, Blue or Rainbow Spring, north-
east of Dunnellon, and Juniper Spring, in the eastern part of
the county, issue from caverns in the Ocala limestone (see
figs. 8, 9).
Sumter County-The southern part of Sumter County is
underlain by the Suwannee limestone. Elsewhere the Ocala
limestone lies near the surface. A well at Oxford entered it at
35 feet (Matson, in Matson and Sanford, 1913, p. 405), and
it crops out between Webster and Oxford. As much of the
county is low and flat, with the level of ground water not far

72 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

i- ** r 49'

,,--,.* "V. y

flu'fi- -^#-

FI 9.Juniper Spring in eastern Marion County. After C E, 199, g. 47.
FIGURE 9.-Juniper Spring in eastern Marion County. After COOKE, 1939, fig. 47.

FIGURE 10.--Ocala limestone in quarry of The Ocala Lime Rock Corporation
near Kendrick. After VERNON, 1943, fig. 12.

GEOLOGY OF FLORIDA-OCALA LIMESTONE 73

below the surface, conditions for quarrying the rock are less
favorable than in Marion County.
Taylor County-The Ocala limestone lies near the surface
in the southeastern end of Taylor County. Elsewhere it is
covered by the Suwannee limestone.
White limestone dug from the bottom of a pit west of
Florida Highway'19, 23.3 miles southeast of Perry and 6.1
miles northwest of the bridge over Steinhatchee River, con-
tains many nummulitic foraminifers, Pecten sp., Peronella
cubae Weisbord, and Schizaster (Linthia) ocalanus Cooke.
The rock above it is hard brown crystalline dolomite, which
may be either altered Ocala or Suwannee limestone. Granu-
lar limestone, probably dolomitic, in a shallow pit east of the
highway one mile from the river seems to be Ocala.

GEOLOGY OF FLORIDA-TERTIARY SYSTEM

OLIGOCENE SERIES

GENERAL FEATURES
The Oligocene series, as interpreted by the United States
Geological Survey, is divided into three parts (Cooke, 1943).
The lowest, which includes the Red Bluff clay and the Forest
Hill sand of Mississippi, is not known to be represented in
Florida. The Marianna limestone and the overlying Byram
limestone together comprise the middle part to which the
name Vicksburg group is now restricted (MacNeil, 1944,
p. 1316). The Suwannee limestone and its littoral equivalent,
the Flint River formation, are of late Oligocene age. For some
years the Tampa limestone and the Alum Bluff group, now
classified as Miocene, were included in the Oligocene. It was
then customary to call the Tampa and the Alum Bluff "up-
per Oligocene;" what is now classified as upper Oligocene
was called "middle Oligocene;" and the present middle and
lower parts were called "lower Oligocene."
There is usually little doubt as to the location of the bound-
ary between the Eocene and the Oligocene where the rocks of
both series contain identifiable fossils, for there is a sharp
faunal break between them. The boundary between the Oli-
gocene and the Miocene is less well defined and is more arbi-
trary, and its determination has varied with different inter-
pretations of the location of the boundary in Germany and
Belgium, where the Oligocene is typically developed (Cooke,
1939b). The selection of the contact between the Suwannee
limestone and the Tampa limestone as the boundary between
the Oligocene and the Miocene is well considered, for the
contact marks a conspicuous change in the lithologic charac-
ter of the rocks and appears to be an unconformity; how-
ever, the faunal difference between the two adjacent forma-
tions is less pronounced than one would like.

DEPOSITS OF VICKSBURG AGE
MARIANNA LIMESTONE
GENERAL FEATURES
Name-Matson and Clapp (1909, pp. 51-52) gave the
name Marianna limestone to ". white limestones of west-

76 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

ern Florida, which are characterized by an abundance of
Orbitoides [Lepidocyclina] mantelli... and Pecten poulsoni."
The local details given by Matson and Clapp (1909, pp. 54-
59) included not only the chimney rock at Marianna, which
may be regarded as typical, but also the Suwannee limestone
near Chipley and elsewhere and the Byram limestone at Mari-
anna and Natural Bridge. Neither of these two formations
had then been named. As restricted by Cooke (1915, 1918,
1923, 1926a), Mossom (1926, pp. 180-181), and by Cooke
and Mossom (1929, pp. 63-66), the name Marianna was in-
tended to apply only to the stratigraphic unit of which the
chimney rock is representative, although some beds since re-
cognized as Byram limestone were included. Cooke (1918,
p. 195) proposed the Glendon limestone as a member of the
Marianna, but it has since been transferred to the Byram
(Cooke, 1943, p. 1714). True Glendon is not known in Flor-
ida, unless the Byram at Ellaville represents this member.
Characters-The most distinctive part of the Marianna is
soft white homogeneous chalky limestone, which can be easily
sawed into building blocks. (See fig. 11.) Because of its ex-
tensive use in building chimneys this limestone is popularly
called chimney rock. According to Mossom (1925, p. 72)
the Marianna limestone contains 93 to 95 percent of calcium
carbonate (CaCOs). The lower ledges of the Marianna are
less pure and are speckled with small grains and patches of
green glauconite. Many exposures of the formation show
several ledges of hard, compact limestone, which stand out
conspicuously from the softer layers between them. Fresh ex-
posures of the chimney rock have a creamy white tint, which
bleaches to chalky white on drying and weathers to dirty gray.
Thickness and distribution-The total thickness of the
Marianna limestone at Marianna is about 30 feet, but in west-
ern Alabama it is as much as 80 feet. The formation has not
been recognized east of Chattahoochee and Apalachicola
Rivers, either in Georgia or in Florida, but it extends west-
ward with remarkable uniformity across Alabama into Mis-
sissippi, where it becomes more variable. As it is overlapped
by younger formations everywhere east of Alabama River,
exposures are confined to river valleys or other suitable low-
lands. Outcrops in Florida are known only in Jackson and

GEOLOGY OF FLORIDA-MARIANNA LIMESTONE

Holmes Counties, where the Marianna is overlapped by the
Flint River formation.
Stratigraphic relations-In Mississippi and western Ala-
bama the Marianna limestone is separated from the Eocene
formations by the lower Oligocene Red Bluff clay, but in
Florida it lies directly on the Eocene Ocala limestone. Cooke
(1923, p. 2) supposed that the Marianna is conformable with
the Ocala and that the lower part of the Marianna is the
stratigraphic equivalent of the Red Bluff clay. However, it
now seems probable that the Marianna overlaps the lower
Oligocene deposits somewhere in Alabama and lies uncon-
formably on the Ocala in Florida.

FIGURE 11.-Marianna limestone. Building-block quarry of Richard Harts-
field, NWY4 sec. 30, T. 5 N., R. 9 W., about 5 miles northeast of Marianna.
After VERNON, 1943, fig. 17.

The Marianna is overlain by the Byram limestone. The
contact at Marianna is a sharp line.
Paleogedgraphy-The Marianna limestone was deposited
in the Gulf of Mexico, which was expanded northward and
contracted eastward, for the Floridian Plateau was probably

78 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

above water then. The shore line (fig. 4) seems to have ex-
tended west-northwestward from Jackson County across
Alabama and southward into the present Gulf, probably lying
along the western side of the Floridian Plateau.
Fauna-Lepidocyclina mantelli (Morton), Pecten poul-
soni Morton, and Clypeaster rogersi (Morton) are the only
commonly identified fossils in the Marianna limestone. All
three were described in 1834 from limestone in the vicinity
of Claiborne, Alabama, then supposed to be of Cretaceous
age, but now included in the Marianna limestone. All are
common in the Marianna throughout its extent. In Alabama,
Bryozoa are locally abundant, and 82 species are listed by
Canu and Bassler (1920, pp. 34-38) from a single lot col-
lected by the writer one mile north of Monroeville, Alabama.
From nine localities in Jackson County, Cole and Ponton
(1930) record 56 species and varieties of Foraminifera. Of
these Lepidocyclina mantelli, L. mantelli papillata, Eponides
mariannensis, and Operculinella dia are the only species that
they supposed to be restricted to the Marianna. It is doubtful,
however, that even these are so restricted, for the most fossil-
iferous bed at Marianna, from which, presumably, most of
Cole and Ponton's collections were derived, is here regarded as
Byram limestone.
One teleost fish of the snapper family, Lutianus avus Greg-
ory (1930), has been found in the Marianna limestone at
Marianna. It is unknown elsewhere.
Utilization-The Marianna limestone is much used locally
as a building stone. From Mississippi to Florida farm houses
within easy hauling distance of outcrops of the Marianna have
chimneys built of blocks sawed from the massive beds of
Marianna limestone. The chimney rock is used to some ex-
tent for walls, but it is too soft and porous to give complete
satisfaction.
LOCAL DETAILS
Holmes County-Vernon (1942) maps the Marianna lime-
stone in two areas in Holmes County, one extending from the
Choctawhatchee River 4 miles northwest of Westville north-
westward to the Walton County line, the other east of Wrights
Creek for 2 miles above Little Gum Creek. The thickest ex-

GEOLOGY OF FLORIDA-MARIANNA LIMESTONE

posure found by Vernon (1942, p. 54) is in a small sink in
the NW' /SE4 sec. 3, T. 5 N., R. 17 W., where he reports
9.8 feet of cream-colored to light-gray massive sandy lime-
stone containing Lepidocyclina mantelli and other Foramini-
fera overlain by 15.9 feet of thin-bedded similar limestone
resembling the Byram formation of Alabama. As authentic
exposures of Marianna limestone contain little or no quartz
sand, it is possible that none of this rock is Marianna.
The westernmost exposure reported by Vernon (1942, p.
55) is in a small sink on the N. C. Spears farm in the NE '
NW 4 SE 4 sec. 26, T. 5 N., R. 18 W., a mile east of the Wal-
ton County line and half a mile southeast of Leonia. He re-
ports Operculinella dia, Lepidocyclina mantelli?, and other
.-Foraminifera from this place. Operculinella dia may indicate
that the rock is Byram rather than Marianna.
Vernon (1942, p. 53) reports 4 feet of cream-colored por-
ous sandy limestone on Little Gum Creek one-quarter of a
mile west of the Hathaway mill in the NW SE sec. 26,
T. 5 N., R. 16 W. He lists Foraminifera and Ostracoda "rep-
resentative of the lower Marianna" limestone. The occur-
rence of the Ocala limestone here or nearby is shown by the
presence of Amusium ocalanum reported by MacNeil (Ver-
non, 1942, p. 53, footnote). Inasmuch as neither the Ocala
nor the Marianna is commonly sandy, and as a good many of
the species listed occur in the Byram, it seems quite possible
that the bed described by Vernon is neither Ocala nor Mari-
anna, but Byram.
Jackson County-The type locality of the Marianna lime-
stone may be regarded as the exposures west of the Chipola
River at Marianna. Matson and Clapp (1909, p. 57) men-
tion a chimney-rock quarry in this vicinity, and there is one
near the road leading to the old bridge. Exposures on this
road and a cut on U. S. Highway 90 near the new bridge, a
short distance upstream from the old bridge, are character-
istic. However, the top of the limestone at both places is
probably Byram. In the cut on Highway 90 the contact of
the Marianna and the Byram is a somewhat uneven line 17
feet above the bottom of the ditch and about 3 feet below
the top of the cut. The following generalized section is based
on sections published by Cooke (1915, p. 109; 1917, pp. 109-

80 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

110) and by Cooke and Mossom (1929, p. 60) and on addi-
tional notes made in 1939.

SECTION ON CHIPOLA RIVER AT MARIANNA
FEET
3. Byram limestone (Oligocene): finely granular crystalline lime-
stone like that exposed along Chipola River south of Marianna.
Pecten aff. P. poulsoni and impressions resembling Lepidocyclina
supera. Exposed in the cut on Highway 90. About - 3
2. Marianna limestone (Oligocene): Massive, homogeneous white
chalky limestone containing Lepidocyclina mantelli and Pecten
poulsoni. Lower part is glauconitic. About - 30
Unconformity.
1. Ocala limestone (Eocene): Soft granular white limestone with
hard ledges in upper part. Composed chiefly of calcareous organ-
isms locally cemented, including Flabellum sp., Terebratulina
lachryma?, Amusium ocalanum, Plicatula sp., and the larger Foram-
inifera listed on page 67. Lepidocyclina fragilis at the top. To
water level, About - - - 14
The Marianna limestone is quarried on the west bank of
Chipola River at the Louisville & Nashville Railroad bridge
below Marianna. Thirty-one feet of soft white chimney rock
is exposed there.
Chimney rock is quarried at several pits east of the river
near Marianna. According to Mossom (1925, p. 147) 20 feet
of soft white chalky limestone containing 97.6 percent of
calcium carbonate is exposed in M. R. Burton's pit 2 /2 miles
northeast of Marianna, and 15 feet of somewhat less pure
limestone in Philip Sexton's pit 13/4 miles northeast of Mari-
anna.
On Penn Street in Marianna 35 feet of chimney rock is
exposed in the SE/4 sec. 29, T. 5 N., R. 10 W., above the
Ocala limestone. The Marianna crops out at several places
along the Springfield road in sec. 21, T. 5 N., R. 11 W., and
its contact with the Ocala limestone was found in the SW /4
sec. 20.
On the land of M. A. Spate a mile and a half north of Cot-
tondale, the soft chalky Marianna limestone is covered by a
foot or less of soil. Eight feet of the limestone, which con-
tains 93.9 percent of calcium carbonate (Mossom, 1925, p.

GEOLOGY OF FLORIDA--OLIGOCENE SERIES

149), is exposed in a small quarry. Mossom (1925, p. 149)
reports a small.exposure of Marianna limestone on the floor
of Rabbs Valley, 3 V2 miles southeast of Cottondale. An anal-
ysis of a sample from the property of G. H. Cartledge shows
97.8 percent calcium carbonate.
The Marianna limestone has been extensively quarried on
the north bank of Blue Spring Creek, 4 miles east of Mari-
anna, for use as building blocks. About 30 feet of rock is
exposed, but only the lower part is quarried. The upper part
contains hard ledges that are not suitable for sawing. Pos-
sibly part of this exposure represents the Byram limestone.

BYRAM LIMESTONE
GENERAL FEATURES
Name-The Byram marl, named from Byram, Mississippi,
was first described by Cooke (1918, p. 196; 1922; 1923, p. 3;
1926a, pp. 287-294; 1935, p. 1164). The first recognition
of the Byram in Florida was by Cooke and Mossom (.1929,
pp. 74-76). The name Byram limestone is here preferred
for the formation in Florida because it seems more appropriate.
As originally defined, the Byram included only those de-
posits of Vicksburg age that are younger than those now
identified as the Glendon limestone member of the Byram.
The Glendon at that time was treated as a member of the
Marianna limestone. Later Cooke (1923, p. 3) raised the
Glendon to the rank of formation on the mistaken assump-
tion that the chert-bearing beds now called Flint River for-
mation (Cooke, 1935b, p. 1170) are equivalent to the Glen-
don and formed part of it. The typical Glendon has since
been reduced again to the rank of a member and placed in the
Byram (Cooke, 1943, p. 1714), to which it appears to have
a closer faunal relationship than to the Marianna limestone.
Mossom in 1925 (pp. 73-77) used the name "Glendon
formation" to include the Suwannee limestone and the Flint
River formation of present usage. Later, Mossom (1926,
pp. 181-182) restricted it to the occurrence of those forma-
tions in northwestern Florida and referred his (1925) so-
called Glendon of the peninsula to the Tampa formation.
This usage was followed by Cooke and Mossom (1929, pp.

82 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

67-93), but they also referred to the Glendon 7'2 feet of
limestone below the so-called Tampa (Suwannee limestone)
on the Suwannee River at Ellaville. That rock may really be
equivalent to the typical Glendon limestone member of the
Byram, though its fauna is more profuse; it is not here dif-
ferentiated from the Byram limestone.
Characters-The Byram in Florida consists chiefly of lime-
stone but includes some clayey beds. Much of the limestone
is sandy. The color is commonly yellow or cream. Most of
the rock is rather soft, or porous, but some ledges are hardened
by deposition of calcium carbonate in the interspaces. On
weathered surfaces, particularly along Chipola River, much
of the lime has been leached out, leaving a soft, porous sand-
stone. The Byram on Suwaninee River is very hard and
weathers into tubular cavities, like the Glendon limestone
member in Alabama.
Distribution-The Byram is typically developed in Missis-
sippi. It occurs also in Louisiana. There are many exposures of
it in southern Alabama. The line of outcrop enters Florida near
Natural Bridge, Walton County, east of which it is over-
lapped by the Flint River formation. The limestone in Holmes
County mapped as Marianna may be Byram. In Jackson
County there are exposures along Chipola River, but none
have been found along the Chattahoochee, where it appears
to be completely overlapped. The Byram reappears along
Suwannee River at and below the mouth of the Withlacoo-
chee. It is unknown in Georgia. ,
Thickness-At Natural Bridge the Byram is probably more
than 40 feet thick. No single exposures as thick as that have
been found along the Chipola. On the Suwannee it is prob-
ably not more than 10 feet thick.
Stratigraphic relations-The Byram directly overlies the
Marianna limestone and appears to be conformable with it.
It is overlain unconformably by the Suwannee limestone or
by the Flint River formation, both of which overlap it.
Paleogeography-The Byram appears to be essentially a
littoral formation, although some of it contains little plastic
sediment. The shore line apparently passed near Vicksburg
and Jackson, Mississippi, and crossed the Florida line east of

GEOLOGY OF FLORIDA-BYRAM LIMESTONE

Florala, Alabama. Its course east of Marianna has not been
determined. The shore line evidently lay somewhere north of
the junction of Withlacoochee River with the Suwannee.
Fauna-The Byram in Mississippi. contains many fossils.
Cushman (1922) describes 68 species and varieties of Fora-
minifera from Byram, and Cooke (1922) lists 5 corals, 134
mollusks, and 2 echinoids from several places within the State.
The fauna may have been just as rich in Florida, but few
fossils have been preserved. The most characteristic species
are Lepidocyclina supera (Conrad) and Anadara lesueuri
(Dall). A thin-margined variety of Clypeaster rogersi (Mor-
ton) is locally common along Suwannee River. Cassidulus
alabamensis Twitchell occurs at Natural Bridge and Ellaville.

LOCAL DETAILS
Holmes County-Although no Byram is mapped in Holmes
County, the limestone there referred to the Marianna may
be Byram. This possibility is suggested in the description of
the Marianna limestone in Holmes County.
Jackson County-The upper 3 feet of limestone in the cut
on Highway 90 near Chipola River at Marianna contains
impressions of a foraminifer resembling Lepidocyclina supera
and a Pecten related to P. poulsoni. The rock is tentatively
referred to the Byram limestone.
The following section was measured in 1914 on the second
hill west of Chipola River along the street in Marianna lead-
ing to the old bridge. The Lepidocyclina is probably L. supera.
A collection (U.S.G.S. 7243) was made from beds 3-6, but
it has been mislaid. Beds 1 and 2 of the section may represent
the top of the Marianna limestone, from which the Byram
had not been distinguished when the section was measured.

SECTION AT EASTERN EDGE OF MARIANNA
FEET
Flint River (?) formation (Oligocene?)
7. Red and orange sand containing a few small pebbles near the
bottom and sparingly throughout; near top are numerous
rounded concretions of ferruginous sandstone. To level of
plain on which city is built - - 40
Unconformity.

84 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

Byram limestone (Oligocene):
6. Yellow compact limestone with hackly fracture 3
5. Brownish-gray calcareous clay containing fragments of lig-
nitized wood - 4- 2
4. Slightly harder ledge of brownish-gray argillaceous lime-
stone containing Lepidocyclina sp. and Pecten poulsoni? 1
3. Brownish-gray calcareous clay containing small Lepido-
cyclina - 3
2. Hard, compact light-gray or cream-colored limestone con-
taining Lepidocyclina and Pecten, a hardened faces of bed 1 1
1. Soft, compact light-gray limestone containing Lepido-
cyclina - ----- 1/2
Yellow granular limestone containing impressions of a
small Lepidocyclina, probably L. super, Pecten sp., and other
fossils crop out at the abutment of the bridge over Dry Creek
in sec. 11, T. 3 N., R. 10 W., about 7 miles south of Marianna.

MacNeil (1944, p. 1331) describes the following section
on a new road leading from Marianna to the Marianna Cav-
erns State Park:

SECTION 0.4 MILE NORTH OF CHIPOLA RIVER
FEET INCHES
Byram formation, Glendon limestone member:
9. Light bluish gray to brown bentonitic clay, largely
weathered, possibly in part a concretion from weather-
ing of bentonitic limestone or dolomite, filling caverns
and solution holes in underlying dolomite, an undulat-
ing line of weathering forming the base - 2+
8. Buff, moderately tough dolomite with prints of fossils 7-
7. Buff, tough dolomite - - 1 6
6. Buff to gray clayey dolomite 10
5. White, hard limestone ledge where unweathered in cen-
ter of cut, passing successively through zone of partly
dolomitized limestone and zone of unaltered limestone
pellets to buff dolomite at ends of road cut 10
4. Buff, tough dolomite with prints of Pecten and Lepido-
cyclina (lens of soft, unaltered cream-colored lime-
stone, with shells preserved, on under side of unaltered
part of zone above) - 5 6
Marianna limestone:
3. Cream-colored, very hard limestone ledge 1 6
2. White, tough limestone with harder concretionary zones 5
1. White, soft, homogeneous limestone 6+

GEOLOGY OF FLORIDA--BYRAM LIMESTONE

MacNeil suggests that the bentonitic clay at the top of the
section probably corresponds to high-grade bentonite in the
Glendon limestone member in Smith County, Mississippi.
Lafayette County-A thin bed of cream-colored limestone,
apparently the Byram, lies between the Ocala and the Suwan-
nee limestones in the northern part of Lafayette County.
Exposures have been noted at the old bridge near Luraville,
where the rock, which contains species of Lepidocyclina,
Turritella, and other fossils, emerges 2 feet above water level
at a stage of 5 feet.
Madison County-Suwannee River, which forms the south-
eastern boundary of Madison County below Ellaville, flows
in a gorge cut through the Suwannee limestone into the Byram
limestone.
Suwannee County-The best-known exposure of the By-
ram limestone is that along Suwannee River below the mouth
of the Withlacoochee, where a thin bed of limestone inter-
venes between the Suwannee limestone and the Ocala lime-
stone. This bed passes below water level a short distance above
the bridge of the Seaboard Railway and is frequently under
water at the mouth of the Withlacoochee. Its extension
downstream is probably not as continuous as it has been
mapped, and its limits are conjectural. Because of the ero-
sional unconformity at its top, which separates it from the
Suwannee limestone, and the erosional unconformity that
must separate it from the underlying Ocala limestone if it is
really Byram, the bed probably varies considerably in thick-
ness. The following section was measured in 1913 at the Sea-
board Railway bridge, which is easily reached from U. S.
Highway 90.

SECTION ON EAST BANK OF SUWANNEE RIVER OPPOSITE ELLAVILLE
FEET
Wicomico (?) formation (Pleistocene):
5. Upper part concealed; lower part is argillaceous yellow sand
containing small pebbles; the top is level with rail at bridge 16/2
Unconformity.
Suwannee limestone (Oligocene):
4. Hard cream-colored to yellow limestone resembling bed 3
but very massive and without bedding planes; Cassidulus
gouldii (Bouvr) very abundant - - 10 '

86 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

3. Hard, compact chalky-white to pink crystalline limestone;
lower 2 feet appears to be brecciated; upper part is thin-
bedded --------------- 4
Unconformity.
Byram limestone (Oligocene):
2. Soft white marly limestone, indurated in places; contains a
few bryozoans and many fragments of Clypeaster rogersi
(Morton)- - - - -- 2
1. White or creamy yellow compact limestone loaded with
molds of mollusks (U.S.G.S. 6824); honeycombed by solu-
tion; extends to water level - - 5$ 2
Bed 1 contains Lepidocyclina supera (Conrad), Clypeaster
rogersi (Morton), Cassidulus alabamensis Twitchell, Olivella
afluens Casey, Mitra conquisita Conrad, and many other fos-
sils, which are preserved only as hollow molds. All of the
species listed occur elsewhere in the Byram, and some of them
are restricted to it.
Although the presence of the Ocala limestone is not indi-
cated in the section near Ellaville it is believed to be exposed
below the Byram at very low stages of the river, and it crops
out above water level farther downstream.

DEPOSITS OF LATE OLIGOCENE AGE
SUWANNEE LIMESTONE
GENERAL FEATURES
Name-The name "Suwannee limestone" was .proposed
by Cooke and Mansfield (1936a, p. 71) for yellowish
limestone typically exposed along Suwannee River in Florida
from Ellaville almost to White Springs. The rock to which
it was applied had previously been called by various names.
Matson and Clapp (1909, p. 73) referred it to the Hawthorn
formation. Mossom (1925, pp. 73-77; 1926, pp. 181-182)
placed it in the Glendon formation, by which name the equiv-
alent beds in Georgia, now called the Flint River formation,
were then known. Later, Cooke and Mossom (1929, pp. 89-
91) transferred it to the Tampa limestone because they recog-
nized its equivalence with limestone in Hernando County
then supposed to be Tampa (Mossom, 1925, p. 79). Further
study has verified both of these correlations, but the beds in
Georgia are now known to be younger than the typical Glen-

GEOLOGY OF FLORIDA-SUWANNEE LIMESTONE

don, and the limestone in Hernando County is now known
to be older than the Tampa.
Characters-In the typical area the Suwannee limestone is
commonly hard and resonant. Small solution holes filled
with green clay, probably residual from the limestone, are
abundant. Where the Suwannee is unaltered, it consists of a
soft granular mass of limy particles, many of them of organic
origin. The color is commonly yellow or cream, locally with
a pinkish tinge. At many surface exposures all the lime has
been leached from it, leaving a porous or massive flint, which
is recognizable as Suwannee by the presence of molds of the
common Suwannee echinoid, Cassidulus gouldii.
In Hernando County the Suwannee is very variable in hard-
ness. It contains patches of hard and soft rock that are irregu-
larly distributed and apparently show no relation to bedding
planes. This variability is especially annoying to quarrymen,
for it causes much waste of rock, their machinery not being
generally adapted to use both hard and soft material.
Chemical analyses (Mossom, 1925) show that the Suwan-
nee limestone contains about 91 to 98 percent calcium car-
bonate (CaCO3) and that the chief impurity is silica (SiO2).
A small amount of iron may account for the color of the rock.
The Suwannee is almost as pure as the Ocala. It is much less
siliceous than the Tampa, which contains a large portion of
very fine sand.
Thickness-Near Live Oak the Suwannee limestone is about .
1QO feet thick. At Falling Water, 4 miles south of Chipley,
a thickness of 65 feet is exposed in the cylindrical sink, which
may not reach the bottom of the formation.
Distribution-The largest area of outcrop of the Suwannee
limestone includes nearly all of Taylor County and parts of
all but one of the adjoining counties. This area expands from
the Gulf of Mexico across the State line into Georgia, where
it is restricted to the valley of the Withlacoochee. Another
large area includes most of Hernando County and parts of
all the adjoining counties. The formation also underlies parts
of Jackson, Washington, and Holmes Counties. Here the
Suwannee limestone is believed to merge northward into the
Flint River formation, and the two are not separated on the

88 FLORIDA GEOLOGICAL SURVEY-BULLETIN TWENTY-NINE

geologic map. Outcrops of the limestone faces are confined
to a strip along the southern border of this area.
Stratigraphic relations-The Suwannee limestone lies un-
conformably on the Byram limestone or, where that is absent,
on the Ocala. It is overlain unconformably by the Tampa
limestone or by the Hawthorn formation (fig. 12). The
contact with the Byram is exposed along Suwannee River near
Ellaville; that with the Tampa on Blackwater Creek in Hills-
borough County, though it is normally under water.
The Suwannee limestone appears to be the offshore equiva-
lent of the Flint River formation, with which it probably
merges in northwestern Florida and in Georgia. Its equiva-
lent in western Alabama and in Mississippi is the Chickasawhay
limestone. These three formations represent the deposits of a
transgressing sea, which extended northward and northeast-
ward far beyond the limits of the Byram and Marianna.

FIGURE 12.-Unconformable contact of the Suwannee limestone (white) below
the Hawthorn formation (dark) in the left bank of Suwannee River about half
a mile above the old bridge on the road from White Springs to Lake City. Photo-
graph by Herman Gunter.. After MANSFIELD, 1937b, pl. C, fig. 1.

	Front Cover
	Title Page
	Copyright
	Table of Contents
	Preface
	Main
	Back Cover

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