Geology of Citrus and Levy Counties, Florida ( FGS: Bulletin 33 )

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Geology of Citrus and Levy Counties, Florida ( FGS: Bulletin 33 )
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STATE OF FLORIDA
STATE BOARD OF CONSERVATION
GEORGE VATHIS, Supervisor
FLORIDA GEOLOGICAL SURVEY
HERMAN GUNTER, Director






GEOLOGICAL BULLETIN NO. 33






GEOLOGY OF CITRUS AND LEVY
COUNTIES, FLORIDA






by
ROBERT O. VERNON
Associate State Geologist
FLORIDA GEOLOGICAL SURVEY


Published for
THE FLORIDA GEOLOGICAL SURVEY
TALLAHASSEE, 1951






















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LETTER OF TRANSMITTAL


HONORABLE GEORGE VATHIS,
Supervisor of Conservation.

SI:

I am transmitting a report entitled "THE GEOLOGY OF CITRUS
AND LEVY COUNTIES, FLORIDA", prepared by Dr. Robert O.
Vernon, Associate State Geologist, with the recommendation that it be
published as Florida Geological Survey Bulletin 33. The study is very
comprehensive and contributes considerable new data to the knowledge
of the geology of the two counties and the geologic history of the State.

It is believed that the report will assist materially in the development
of the mineral resources of the counties and the State and some of the
data will help in the search for oil and gas.

The Geological Survey sincerely appreciates your cooperation and
continued interest in its work.

Respectfully yours,

HERMAN GUNTER, Director
Geological Survey


Tallahassee, Florida


June 15, 1951








PREFACE


The writer has attempted to present the high points of the geologic
history of Citrus and Levy counties and adjacent areas so that they can
be understood readily by both the citizens of the State and by the geo-
logist. All of the geologic information available on these two counties,
the large part of which has been collected by the writer and others in
the field, has been assembled and detailed descriptions of the physio-
graphy, economic resources, and geology are printed in a form intended
for the convenience of those interested for scientific study or economic
development.

Special attention is invited to the structural map drawn on top of
the Inglis member of the Moodys Branch formation, to the map of the
fracture patterns and to the geologic sections. These may provide some
additional data for interpreting geologic history having a bearing on oil
and gas explorations. Certainly the preparation of a map based on a
specific top will be more significant than the map of the eroded surface
of the Ocala limestone, formerly used as a reference datum for studying
Tertiary structure in Florida.

The chapters on the detailed geologic history provide information
about the formations penetrated by deep oil test wells and about younger
beds of Eodcne to Recent age that crop out at the surface. This in-
formation can be used to compare these beds with beds of similar ages
in other states, and makes it possible to subdivide some of them in
Florida. Information on beds that are exposed at the surface in Levy
and Citrus counties, is presented as an areal map on Plate 1.

The final chapter gives descriptions of the dolomites, limestones,
limonite ore, sand, clay and phosphate with recommendations for further
exploration and exploitation. Some attempt is made to estimate the
probable tonnage of material available in these counties and to evaluate
the economic possibilities of development.






ACKNOWLEDGMENTS


Messers W. A. Jenkins, Walton Jones, Clarence Simpson, Robert Neill,
Robert Hart, Lester Chastant, Alfred Fischer and Ralph Heath, all mem-
bers or former members of the State and U. S. Geological Surveys at
Tallahassee, have assisted in the field work. Geologists and paleontologists
of the oil profession located in Tallahassee have been most helpful in
discussions of problems. In particular, the members of the Exploration
Department of the Humble Oil and Refining Company have contributed
freely and unselfishly their time and experience in the study. Members
of the Southeastern Geological Society have been interested in the study
and contributed much information in informal discussions, particularly
during the Fifth Field Trip of the Society in these counties on December
5-6, 1947. Mr. H. H. Cooper, Jr., District Engineer of the Water Re-
sources Branch of the U. S. Geological Survey, Tallahassee, Florida, has
been most helpful in the development of some of the discussion pertain-
ing to hydrology, dolomitization and structure.

Considerable incidental assistance has been given by many others,
and the writer is particularly grateful to these workers: Dr. H. B.
Stenzel, Geologist, Bureau of Economic Geology, Austin, Texas, identi-
fied some of the mollusks and prepared a preliminary check list of these.
Dr. Horace G. Richards, Assistant Curator, The Academy of Natural
Sciences, Philadelphia, Pennsylvania, also has identified and is pre-
paring a paper on the molluskan fauna of the area. Dr. A. G. Fischer,
while with the Survey, prepared a paper on the echinoids of the Eocene
beds and on the destructive analysis of carbonates of the area. The first
paper is published in Florida Geological Bulletin 34, and the second is
to be published as a Report of Investigation. Dr. H. V. Howe, Director,
School of Geology, Louisiana State University, Baton Rouge, Louisiana,
studied the fauna of an Avon Park limestone locality and prepared a
paper on the ostracodes, published as a part of Bulletin 34. Dr. K. P.
Oakley, British Museum, London, England, has kindly studied certain
concretions. As members of the Florida Survey, Mr. Charles Hendry
contributed many hours in preparing maps and illustrations from rough
sketches, Mr. Carlton Gray and Mr. William Henry assisted by picking
foraminifers and ostracodes for identification and Mr. Hal Chittum, Jr.,
ran precise levels on many outcrops and all of the wells in the area.
Drs. James L. Calver and Herman Gunter and other members of the
Survey have offered many suggestions for factual presentation and clear






statement in editing. Mrs. Mary Blount prepared the manuscript from
difficult copy and also helped in editing.
Paul and Esther Applin of the U. S. Geological Survey, Tallahassee,
Florida, edited portions of the paper, particularly that of the Mesozoic
and older rocks. Dr. John Charles Rabbitt of the U. S. Geological Sur-
vey analyzed four samples of phosphate used in correlation of the
Miocene and Dr. Earl Ingerson of the U. S. Geological Survey, Wash-
ington, D. C., identified some clay minerals. Dr. A. F. Greaves-Walker,
R. S. Hagerman and other members of the clay laboratory of the Florida
Engineering and Industrial Experiment Station, Gainesville, Florida, fired
several samples of clay and evaluated the possibility of developing these.
Mr. Donald W. Gravell, Cabon Gref Oil Company, Havana, Cuba; Mrs.
Marie de Cizancourt, Paleontologist, Paris, France, and Dr. Louise
Jordan, Independent Paleontologist, Tallahassee, Florida, have all identi-
fied some of the foraminifers of the Eocene.
The study could not have been completed without the help and
courteous attention of the citizens of these counties. In particular, I wish
to express my thanks to R. W. Saults, Sr., R. W. Saults, Jr., L. K. Runnels
and Ben Robinson who directed me to many localities and helped, in
completion of the work over difficult terrain.






TABLE OF CONTENTS
PAGE
Letter of transmittal ----------_----------_-- ---------- ---- ---------.-.._ III
Preface ____...--------------_ -------------- IV
Acknowledgements V__---_---------------------- ------ V
Geology of Citrus and Levy counties, Florida .. ---------------------.. ----- 1
Introduction 1.- --------------_ 1-------------------
Scope of study -1-----.-_----___---------- 1--------
Location of area 1--------_...... .......-------------------_---- 1
Maps ----------------------------------------- 2
Towns 4--.. .. ........ ...... __ .....-------------4----
Transportation ............... 6-------------------------------
Climate and vegetation -----g------------------------------------ 9
Culture and land utilization ....... ----------- --.. 11
County names .......... .. --------------- -- 11
Population ------- --------11
Land utilization ---------- ---12
Physiography ...---------------...- ----------- ----- 14
Introduction -- ------------_ ------------------------ 14
General land forms of Florida ------------------------------ 14
Geologic controls --------- ------ 16
Physiography of Citrus and Levy counties -----------__.....------- 17
Introduction _..--------------------------- -- 17
Tertiary Highlands ----_---_..-----__.----..........------------------ 18
Delta Plain Highlands ..... ..... .... .........--------_-------8.. 18
Terraced Coastal Lowlands ----- __- __ ___19
Modern submarine plain --_ -- ------------_._20
Coastal terraces --- ----.--. 21
", Pamlico terrace -._------____ ~__- 22
Wicomico terrace __---------__ 25
Chiefland Limestone Plain ------_--- 25
Coharie-Okefenokee Sand Ridge ----- _____ 25
River Valley Lowlands ---- --------____ 27
Stream valleys __--__---------- __ 27
Stream terrace sediments -----.--____-__ 28
Suwannee River Valley Lowland ---- ____-_ 29
Withlacoochee River Valley Lowland --- ------ 29
Tsala Apopka Lake -..... ---------------------------- 30
Waccasassa River Valley Lowland -------- 31
Williston Limestone Plain 8---_____________ 32
Stream capture ----------833
Pleistocene history in Florida 36
Terraced Coastal Lowlands 36
Stream valleys in western Florida --- ------41
Stream valleys in Citrus and Levy counties ---- 41
Keys _------_____----- 42
Solution -- __-------------42
Introduction -------_.----.-------------------.-... 42
Caverns -43
Sinks _---------------- 44
Lakes _--.~__--------44
Long Pond _____-----------46
Springs ---__- _----------- -----46
Fracturing -------------- 47
Structure and sections _----------- 53
Introduction ----------------53
Ocala uplift ____~__-------------54
The Kissimmee faulted flexure ------___-- 56
The Sanford high --------- --------------------- 57
The Osceola low -- ___~----------57







Structures within Citrus and Levy counties ----._.. -----
Domes --...--.. ----------- -------- ---
Homosassa Springs dome -------
The West Levy dome --------
Faults ----
Bronson graben -----------------------------.
Inverness fault ----------
Long Pond fault ----------
Dates of structural movements -- __ --_ -
Stratigraphy ..
Previous work ---..--_.... ....-- ......-----------------
Florida general stratigraphy and structure -
General stratigraphy of Citrus and Levy counties ----
Paleozoic era --------
Preliminary notes on the Paleozoic strata beneath Citru
counties, Florida, by Jean Berdan and Josiah Bridge --
Mesozoic era---- ------------- --
Triassic system --- ------
Cretaceous system ----------.-...... .... .------ -----.
Introduction -....-----------
Lower Cretaceous (?) (Comanche series) --..-
Upper Cretaceous (Gulf series) ----_ ----
Atkinson formation ---.--__.-----
"A zone" ...---------
"B zone"
Beds of Austin age ----- --
Beds of Taylor age ----_ --...-
Lawson limestone (Navarro equivalent) __---


------- --
---------
----------
- - -


Cenozoic era ....---- ----------
Tertiary system ------- -------
Paleocene series --
Cedar Keys formation -------------...........
Eocene series _--- ----
Oldsmar limestone
Claiborne group ---------
General nomenclature --------
Regional correlation ----------------
Lake City limestone ----_...........------------
Avon Park limestone -----------------
Jackson group ----........ ...---- --- ---- ----------
History ----- --
Jackson-Claiborne contact --------------.
Moodys Branch formation --------------------------
Introduction and definition ------------... --------
Inglis member --......-----------------
Williston member ---------
Ocala limestone (restricted) .----- .......-------------
Oligocene series -....--... ---------------------
Introduction --_--------
Suwannee limestone ---------
Miocene series ..----.-------------
Introduction -.---------
Miocene problem --- ------
Pre-Miocene surface --_ ----......- ---.-
Geologic history of the Miocene ---
Hawthorn formation .---..-... ....--------------
Alachua formation ------------
Origin of phosphate .-- ----
Mineralogy of the phosphate deposits -------
Quaternary system .-----------
Pleistocene series ---- ------
Introduction __...---.-- -------


PAGE
58
58
59
60
60
60
60
61
---- 61
-63
68
---.- 63
64
66
68
Levy
68
71
-71
.. 74
74
76
77
-- 78
-- 79
S79
-- 80
81
-- 82
-- 84
------ 84
84
----.. 84
---- 84
-86
---. 86
--. 88
-- -- 88
.. 89
90
95
-.. 111
111
..-- 113
... 115
-.---. 115
... 115
141
.--- 156
-.-.. 172
172
173
.- 178
.-- 178
181
--..- 183
-- 183
.-- 186
189
195
--- 200
.----- 208
--..-- 208
.---. 208






PAGE
Pre-Pleistocene surface .... --------------- ----- 209
Stratigraphy __- .---------- ---- ---.- 210
Recent series .. ----------------------------- 2215
Fresh-water marls .---------------- ------- 216
Peat and muck ------------------ 216
Economic Geology .-----. --------------------217
Introduction .------------------------- 217
Limestone ------------------------------------------ 217
Dolomite rock ----------------------------------------- ----- 221
Phosphate rock ----------------------------- 224
Introduction ...... .. .. ------------------------ 224
Hard-rock phosphate -------------- 224
Colloidal phosphate-clay ------------ 228
Clay deposits .-------------- ----- 280
Cement ------------ ---- 233
Chert ----------------- 234
Sand ------------------------------------ 234
Limonite --- ------------.---------------- ------ 235
Possibilities of oil and gas production -------------- 237
Possible oil bearing horizons --------------------------------- 237
Favorable structural features _------------------ 238
Previous oil tests ---- -------------- 240
Surface water -------------------- 240
Ground water -- .------------------------------ 240
Date of artesian system ----------------- ------ 243
Mineral production ---------------244
Bibliography ____-----------__----------------------------------------------- 247
Index ------------ -------------------------- 253





ILLUSTRATIONS

Frontispiece-Fault breccia at Crystal River Rock Company quarry ---.-


PAGE
S II


Plate 1

2

Table 1
2
3
4
5
6
7
8
9

10

11

12
13
14
15
16

17
18
19
20
Figure 1
2
3
4
5

6

7
8
9
10
11

12

13
14
15
16
17
18

19
20
21

22

23


Geologic map of Citrus and Levy counties,
Florida-In pocket
Structure map of the northern peninsular
Florida-In pocket
Climatological data -........ ------- ----------- 10
Land utilization ----------------- 12
Forest production -------------------- 12
Agricultural products -----...-..._ --- ------- --------- 13
Correlations of Pleistocene terraces _.......----- -- ----- 40
Geologic formations in Citrus and Levy counties, Florida --.-- 67
Paleozoic rocks in Citrus and Levy counties -____---__........----------- 72
Wells that penetrate the Lake City limestone _--------.--- 94
Comparison of Alabama and Florida sections of upper and late
middle Eocene deposits -........----------. ---------------------- 112
Checklist of foraminifers of the
Moodys Branch formation ----... _----------- Between 140 and 141
Wells that penetrate the Avon Park limestone
and younger beds -__... -.------- --------------- 153 to 155
Well data at the type locality of the Ocala limestone ----- 156
Ocala limestone exposure in the vicinity of Williston ---___ -- 163
Miocene rocks in peninsular Florida ______..- ..--- 183
Complete analyses of phosphate-rock samples --- -- 202 to 203
Age and elevation of the Pleistocene formations in Citrus and
Levy counties .- --------------.--- 209
Tests of clays -.....------------------------ 232
Oil and gas tests in Citrus and Levy counties ..- --------..-. 239
Mineral producers in Citrus and Levy counties, 1944-49 _--_. 244
Mineral production in Citrus and Levy counties, Florida, 1944-49 246
Location map -------------- 3
Physiographic map ----- -- -- Between 18 and 19
Terraced Coastal Lowlands as seen from the Tertiary Highlands -- 19
Drowning of coastal margins ----__ ---- -- --- 21
Mosaic of aerial photographs illustrating physiography and the
trace of the Long Pond fault ..2------ ----------------- ----- 22
Limestone of Inglis member, Moodys Branch formation paving
the coastal hammocks _..--- --.. -------.--------------------------- 24
The Chiefland Limestone Plain --_____ ------------ ------------------ 26
Broad ancestral valley of the Waccasassa River _-- -- 32
Aerial photograph of the ancestral valley of the Waccasassa River 34
Solution pipe in the Ocala limestone ------------------ 45
Fracture pattern of the northern part of the
Florida Peninsula ----------- -- Between 48 and 49
Differential weathering of the limestone of the Moodys Branch
formation -- -- ------ -------------- -- 51
Geologic sections .....---------.. ....... -------------- Between 54 and 55
Geologic section along the proposed "ship canal" -_ Between 56 and 57
The principal structures in Citrus and Levy counties -- 59
Cretaceous sections and structural map -.------ Between 76 and 77
Lake City limestone sections and structural map -. Between 94 and 95
Exposure of the Avon Park limestone and Moodys Branch forma-
tion at the Florida Power Corporation dam ...-__.-...------------------ 100
Avon Park limestone in sink at locality L-119 _---- -- 108
Type locality of the Inglis member, Moodys Branch formation -- 123
Contact of Williston and Inglis members, Moodys Branch forma-
tion, south of Chiefland --.--- -- -- -- 128
Contact of Williston and Inglis members, Moodys Branch forma-
tion, east of Chiefland .. -----.--------- -- 129
The Inglis member near dam of Florida Power Corporation 1--- 131





PAGE
24 Contact of Williston and Inglis members, Moodys Branch forma-
tion, north of Crystal River __ --- ------ 133
25 Cross-bedded limestone of Inglis member ------ 136
26 Type locality of Williston member of the Moodys Branch
formation ______ ______ ___----------------- 145
27 Williston member at locality L-17 ----_- 150
28 Pinnacles of the Williston member extending into the Alachua
formation _____------- ..._ ------- ------------ 152
29 Twenty-three feet of Ocala limestone (restricted) near Williston __ 163
30 Exposure at Crystal River Rock Company quarry ---- 168
31 Contact of the Suwannee and Ocala limestones at the Crystal
River Rock Company quarry -------- 169
32 Exposures at the Thomas pit __------------ 172
33 Isopachous and structural map of the Miocene
of Peninsula Florida -------- Between 180 and 181
34 Irregular limestone surface, a Karrenfeld, lying beneath the Alachua
formation _____------------____________------- 194
35 Pinnacle of limestone extending into the Alachua formation at
the Section 12 Mine, Kibler-Camp Phosphate Enterprise --..-.. 196
36 Sand and clay of the Alachua formation exposed at Crystal River
Rock Company quarry -.._------ .----- ----..__---- 205
37 Distribution of the economic deposits in Citrus and Levy counties 218
38 Pit of the Connell Schultz Company illustrating mining methods --_ 219
39 Flow sheet for the Section 12 Mine, Kibler-Camp Phosphate
Enterprise _-- __.. --- --- --------- ---.---- 227
40 Piezometric surface of Florida _-__ -----__242











GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA
Robert O. Vernon

INTRODUCTION

SCOPE OF STUDY
The location of Citrus and Levy counties, Florida, on the crest of
the Ocala uplift, and the presence of good exposures, make the area
favorable for field study and also make it a critical one in Florida
Tertiary stratigraphy.
The study was begun in early 1947, following a field conference of
geologists, when it became apparent that the area would have to be
mapped in detail to obtain a more complete understanding of the strati-
graphy. This work was accomplished largely through intermittent trips,
no defiinte full time being available. Swamp areas in the counties were
accessible only when water levels in the swamps and hammocks were
at their lowest. During the latter portion of the field study it became
desirable to trace the rock units and correlations recognized in Citrus
and Levy counties into adjacent counties. Accordingly a detailed study
of samples from approximately 1,350 wells in 35 counties was under-
taken and the units mapped at the surface were identified in each of
these wells and correlation points were extended into the subsurface.
Many of the wells were located in general terms and elevations were
not available. It was deemed necessary to establish accurate controls on
each well used and the survey was made on all wells in the 35 counties.
Only those wells for which accurate controls were available, or were
determined, were used in the preparation of the structure and isopach
maps.

LOCATION OF AREA
Citrus and Levy, adjoining counties, are located on the west coast
approximately in the center of the Peninsula of Florida between lati-
tudes 280 30' and 30 00' North where the coast has a deep indenture,
see figure 1. Because of the large number of islands these counties have
a long coast line that resembles the coast line further south in Monroe
County.
Levy County is bounded to the northwest by Dixie County, the
county line being drawn along the Suwannee River; to the north by






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Gilchrist and Alachua counties, and to the east by Marion County. To
the south Citrus County is separated from Levy County by the Withla-
coochee River which circles Citrus to the east and is the county line
between Citrus and portions of Marion and Sumter counties. Hernando
County lies to the south.
The two counties measure about 46 miles in width and 61 miles in
length and the total area, including Gulf and islands is 1,798 square
miles. Levy County is about 1,137 square miles, made up of 1,103 square
miles of land and 34 square miles of lakes, and Citrus County is 661 square
miles in area, composed of 570 square miles of land and 91 square miles
of lakes.1
These counties are sub-tropical and have a low relief. The highest
point in the counties, slightly above 220 feet, is in Citrus, but most of
the area is below 50 feet in elevation. The coastal areas are commonly
rocky although marshy, the coastline being indented by many bays and
inlets.
The location of Citrus and Levy counties in the warm water em-
bayment of the Gulf causes winters to be warmer and the summers to
be cooler than the average seasonal temperature of the interior. The
regular sea breezes and afternoon showers reduce the temperature
during the summer and the warm currents of the Gulf moderate winter
extremes.

MAPS
When the field work in Citrus and Levy counties was undertaken
almost no maps showing accurately either physical features or the
culture of the area were available. A complete set of U. S. Department
of Agriculture aerial photographs covering both counties were available
and field maps were constructed from these photographs. The plani-
metric maps of the U. S. Coast and Geodetic Survey, based on aerial
photographs and covering the Florida Gulf Coast, were most helpful
during the latter part of the field work. Topographic maps covering
the eastern portions of both counties were published in 1890 and 1893
by the U. S. Geological Survey, but the culture and topographic controls
were so inaccurate and out-dated as to render these maps practically
useless. State Road Department county maps and the official surveyed
sectional land grid, filed with the land office of the State Department
of Agriculture, were used in plotting sections, townships and ranges. The

1Sixteenth Census of the United States, 1940.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


!S iACKSON















LOCATION r-
OF
CITRUS AND LEVY
COUNTIES, FLORIDA


0 50 100 200

_2N Scale in miles
25*N





Figure 1. Location of Citrus and Levy counties, Florida


base map published as Plate 1 was compiled largely from aerial photo-
graphs and U. S. Coast and Geodetic Survey hydrographic and plani-
metric maps upon which the sectional grid was superimposed. A list of
maps covering the two counties, some of which were used in the field
work, follows:

U. S. Department of Interior, U. S. Geological Survey, Topo-
graphic Quadrangles on a scale of 1:62,500 with a 10-foot
contour interval:

Dunnellon Sheet, 1890
Panasoffkee Sheet, 1893





FLORIDA GEOLOGICAL SURVEY- BULLETIN 33


Tsala Apopka Sheet, 1893
Williston Sheet, 1893
Florida State Road Department, Division of Research and Records,
Maps on scales of 1:63,360 and 1:126,730:
Citrus County, 1936, Revised 1948
Levy County, 1936, Revised 1946
U. S. Department of the Army, Corps of Engineers, Series of plani-
metric maps along the proposed Cross-Florida Barge (Ship)
Canal on a scale of 1:10,000 with partial topography on a con-
tour interval of five feet, 1933:
U. S. Department of Commerce, U. S. Coast and Geodetic Sur-
vey, Planimetric maps on a scale of 1:20,000, compiled from
aerial photographs, 1940:
Chart T-5791 Suwannee River and Vicinity
T-5792 Cedar Keys and Vicinity
T-5793 Sumner and Vicinity
T-5794 Gulf Hammock and Vicinity
T-5795 Waccasassa Bay and Vicinity
T-5796 Withlacoochee River and Vicinity
T-5797 Crystal River and Vicinity
T-5798 Homosassa Bay and Vicinity
U. S. Department of Commerce, U. S. Coast and Geodetic Survey,
Nautical charts on a scale of 1:80,000:
Harbor Chart 480, Cedar Keys, 1930
Coast Chart 1258, Anclote Keys to Crystal River, 1944
Coast Chart 1259, Crystal River to Horseshoe Point, 1943

TOWNS
Bronson is the county seat of Levy County, and Inverness of Citrus
County. Both were founded in the prosperous days of hard-rock phos-
phate mining, but their importance is now due largely to their being
the seats of county governments. Numerous pits of former phosphate
mines exist about each, although income is now derived largely from
agriculture and tourist trade, attracted by the excellent hunting in the
hammock areas and fishing along the coast, Suwannee and Withlacoo-
chee rivers and numerous lakes in the counties. Some citrus is grown in
the vicinity of Inverness and many small lumber mills operate in the
backwoods of Bronson. Additional income is derived from grazing native
herds of cattle and hogs, although the trend in the area now is toward





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


better bred stock. The county seat of Levy County was formerly at the
small settlement of Levyville, now abandoned except for one or two
houses. The shift to Bronson was occasioned by the building of the At-
lantic, Gulf and West Indies Tourist Company Railroad, popularly called
"The Yulee Railroad", which passed through Bronson and by-passed
Levyville.
Chiefland, in the northwest part of Levy County, is in a prosperous
farming, turkey and stock raising section. Watermelon, peanuts and
corn are the chief crops and large shipments of watermelons are made
over the Atlantic Coast Line Railroad which serves this area. Both of
the main highways along the western coast of Florida pass through
Chiefland, and it is developing into a rather prominent tourist, fishing
and hunting center. Doublesink, Newton and Meredith are all small
farming settlements. Meredith is a remnant of the hard-rock mining
activity and was a stop on a railroad, now abandoned, that formerly
connected Key West with Gainesville in Alachua County and serviced
the phosphate industry.
Williston is the center of the second largest limestone mining area
in the State. The soft limestone of Eocene age is mined here by six
companies which have operated intermittently. Eve, Raleigh, Runnels,
Montbrook and Morriston are all small settlements deriving their income
from farming, stock grazing and minor limestone industries. Considerable
chert, residual from the erosion of limestone, occurs in this area, particu-
larly about Montbrook and Morriston, and the farmers obtain some in-
come from selling these boulders, picked out of their fields, to rock
crushers that are operated intermittently. These settlements were all
established during the hard-rock phosphate mining activity.

Cedar Keys, located in the southwest part of Levy County on a
white sand key in the Gulf of Mexico, is a small fishing village, the
remnant of a formerly much more prosperous town. It was once an
active port and railroad terminal that supported several hotels, a customs
house and weather station. Its prosperity was due to the building of
"The Yulee Railroad" connecting Fernandina with Cedar Keys and to
the former freight traffic on the Suwannee River. Some of the best cedar
in the nation grows in Gulf Hammock and a thriving industry was
created in cutting and shipping this timber for use by pencil manu-
facturers. Cedar is no longer cut for this purpose. The abandonment of
"The Yulee Railroad" during the War Between the States and the com-
pletion of a railroad into Tampa made Cedar Keys less important as a
port and decreased the usefulness of the Suwannee River freight ships.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


The town population and prosperity decreased rapidly. Fishing, oysters,
sponges, and a small company manufacturing brushes from the fibers
of the palmetto and palmetto palm are its chief industries now.
Sumner, Rosewood, Ellzey, Otter Creek, Gulf Hammock, Lebanon
and Tidewater are all small saw-mill towns which were developed about
the rim of Gulf Hammock, a source of large quantities of hardwood, now
largely depleted. Timber mills are operated at all of the towns at
present with the exception of Sumner and Tidewater where turpentin-
ing is the principal industry. Otter Creek manufactures slats for use in
crates. The town of Gulf Hammock is owned largely by Patterson Mac-
Innis Lumber Company whose headquarters and lumber mill, the
largest in the area, are located here. Additional income is obtained
through hunting, fishing and trapping. Wild game, both salt- and fresh-
water fish and valuable fur animals, including mink, otter, and fox, are
found in the extensive swamps and coastal marsh lands of the western
Peninsula.
The small farming and cattle raising settlements of Lebanon in Levy
County and Red Level in Citrus County are the sites of dolomite pits;
Citronelle is the center of a small turpentine industry; Crystal River,
Homosassa Springs, Homosassa and Chassahowitzka are centers of hunt-
ing, fishing and recreation for tourists and commercial fishing. Crystal
River is also a small port for pleasure boats and is the terminal of a
branch line of the Atlantic Coast Line Railroad. Some limestone is pro-
duced near Crystal River, and in former years large tonnages of road
base materials were mined and shipped.
Holder, Felicia, Hernando, and Floral City are small settlements that
were founded during the former activity of the hard-rock phosphate
mining industry. Income is now obtained from stock raising, tourist
recreation, fishing, hunting, the clay-phosphate industry, the hard-rock
phosphate industry near Holder and a small clay pit near Floral City.
Lecanto is a prosperous small farming and stock raising center.

TRANSPORTATION
Highways
Before 1943, when U. S. Highway 19 (State Road 55 on Plate 1)
was constructed as the coastal route to St. Petersburg and several con-
necting roads were paved, the few highways that crossed Levy and
Citrus counties were poorly connected by unpaved roads. Many of the
small hamlets of the counties grew rapidly after these roads were com-





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


pleted, expanding to the demands of the large tourist travel along U. S.
Highway 19. The area now is a desirable and available hunting, fishing,
and recreation center.
The two principal highways along the western part of peninsular
Florida, U. S. Highway Nos. 19 and 41, cross Levy and Citrus counties.
U. S. Highway 19 traverses the center of Levy County and the western
side of Citrus County, connecting Chiefland, Otter Creek, Inglis, Crystal
River, and Homosassa Springs with points north and south. This high-
way passes through very beautiful, flat land and skirts a jungle of high-
land swamps, called hammocks, that teem with bear, turkey, wild hogs,
mink, otter and other game. The trees are majestic hardwoods and the
hammocks are truly tropical and preserve much of the wild beauty
typical of Florida. Several large springs are easily reached from U. S.
19. The springs of Crystal River well up from deep canyons and fissures
to make Crystal River and may be seen from glass-bottomed boats.
Homasassa Springs and Chassahowitzka Springs rise in the lower ham-
mocks of southern Citrus County and their blue waters are exceptionally
clear. Homosassa Springs is inhabited by a variety of both salt- and
fresh-water fish, which congregate in great numbers in crevices of the
spring and are easily visible from platforms constructed out over the
spring and from underwater caissons. The springs are well-developed
commercially and are a well-known tourist attraction. One of the pret-
tiest small springs in Florida, visible in its natural setting, also can be
reached from U. S. 19. This spring, Wekiva Springs, is set in the sand
hills east of the town of Gulf Hammock, where it rises from a fissure and
makes a small creek that flows along a valley made of steep limestone
walls, apparently a former cavern with the top now collapsed or removed
by solution.
The other important highway crossing these counties is U. S. 41,
which in part is also U. S. 27. It enters Levy County along the eastern
projection of the county and connects Williston and Morriston with
Dunnellon in Marion County and then continues along the eastern part
of Citrus County, paralleling the beautiful Tsala Apopka Lake, a recog-
nized fishing area, and connecting Hernando, Inverness, and Floral City
with Tampa, Sarasota, Fort Myers, and Miami to the south and Lake
City, Jasper and eastern coastal states to the north.
There are numerous paved and unpaved but improved connecting
roads of which State Road 500, connecting Chiefland, Williston and
Ocala; State Road 24, connecting Cedar Keys, Bronson and Gainesville;
State Road 44, connecting Crystal River, Inverness and Leesburg; and





FLORIDA GEOLOGICAL SURVEY BULLETIN 33


State Road 55, connecting Chassahowitzka with Floral City, are im-
portant.
Railroads
The area is served by the Atlantic Coast Line and Seaboard Air Line
railroads. The Atlantic Coast Line Railroad connects Wilcox, Gilchrist
County, with Chiefland, Otter Creek, Gulf Hammock, Lebanon Station,
Levy County, and Dunnellon in Marion County, where it joins a branch
of the line crossing Levy and Marion counties. Shipments made on this
line include watermelons, peanuts and corn from the Chiefland and
Wilcox areas, timber from the Otter Creek and Gulf Hammock areas,
limestone from the Williston area, dolomite from the Lebanon Station
area, and soft phosphate from the Dunnellon area.
Both the Seaboard Air Line and the Atlantic Coast Line have branch-
es that cross Levy and Citrus counties along the eastern edges. The
Atlantic Coast Line serves Crystal River and formerly handled consider-
able timber from the large hammocks of southern Citrus County, but
now handles minor shipments of limestone, some timber and naval stores
and some stock. The main lines of both railroads serve the Williston lime-
stone industry and the hard-rock phosphate industry south of Dunnellon
in Citrus County. The only phosphate plant in operation at present is
served by the Seaboard Air Line, but in the past when more pits were
operated both railroads served the industry. Some clay for use in the
Portland Cement Plant in Tampa is shipped from near Floral City over
the Seaboard Air Line.
Excellent passenger service is maintained by both railroads over the
principal routes connecting Tampa and St. Petersburg with the north.

Airways
No flights are scheduled into any town of Citrus and Levy Counties
and no commercial airports are maintained.

Waterways
Inglis is a port of entry and is the western terminal of the proposed
Florida Barge Canal. The town lies on the Withlacoochee River which
is navigable approximately to Dunnellon by small cabin boats, which
must pass the power dam at Inglis through locks. The river is navigable
to Inglis by sea-going tugs and shallow-draft boats, a channel of nine
feet being maintained from the Gulf to Inglis.
The lower portions of all other streams on coastal water of the area





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


are navigable by small cabin boats, but all head waters are rocky and
shallow and log jams are common.
Following the construction of "The Yulee Railroad" and subsequently
that of the major railroads operating in Florida today, waterways in the
counties have gradually decreased in importance as transportation ways.
Some oil is barged up the Withlacoochee River to the Florida Power
Corporation Plant at Inglis and rarely some timber is barged. Prior to
the development of railroads, and later the highways, the Suwannee
River was an important water way, supplying freight to stores and towns
scattered along its banks up as far as what is now Branford, although
some shallow-draft boats may have reached the shoals at Ellaville
during high water.2 The usefulness of these freight ships has ended and
the former river prosperity has dwindled accordingly.

CLIMATE AND VEGETATION
Citrus and Levy counties are low-lying, sub-tropical, coastal land areas,
bordered on the west by the warm Gulf waters. Citrus is more tropical
than Levy which is rather temperate. Sharp changes in climate occur
at about the latitude of the Citrus-Levy county line. Citrus County
averages about seven inches more annual rainfall and 20 to 30 days
additional each year without a killing frost, although the climate of
coastal areas of Levy County approaches that of Citrus County.
Numerous spring-fed sluggish streams drain into the Gulf of Mexico
from a poorly defined divide of sand hills extending along the eastern
margins of both counties. The coastal margins are low, flat and rocky,
and the coast line is broken by many marsh and bay inlets. Islands are
numerous. Many inland lakes, particularly Tsala Apopka Lake which
is the largest in the counties, temperate the climate.
Citrus and Levy counties have an annual rainfall about three inches
less than the average for Florida, the three permanently maintained
weather stations in the counties recording an average rainfall of 49.99
inches during the years 1841 to 1949.3 Most of the rainfall comes during
the months of June through October, usually falling as heavy rains
during thunder-storms in the afternoons. Cooling winds with high
velocities commonly accompany these local storms.
The area is in the hurricane belt and these tropical disturbances pro-
duce winds of very high velocity and destructiveness, but damage is
2Personal communication, J. C. Simpson, 1950.
3U. S. Weather Bureau, "Climatological Data", published monthly.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


commonly restricted to paths up to 80 miles wide and the area has gone
many years between visits of hurricane winds. The latest hurricane to
cause extensive damage was in 1950 when the lowlands were flooded
by high seas and high winds caused some damage along exposed coasts.

Temperatures over the counties range from an average of 81.4 de-
grees Fahrenheit in the summer to an average of 58.4 degrees Fahren-
heit in the winter. Daily fluctuations vary from about 18 degrees in the
summer to 25 degrees in the winter, although extremes in the winter
months may approach 50 degrees. The days are commonly comfortable,
but the nights are cool. The relative humidity may be as high as 90 per
cent, and when combined with a high temperature and little air circu-
lation the physiological effect may be close and muggy. Fortunately, the
afternoon rains, associated winds and moderating effects of Gulf waters
prevent extreme temperatures in the summer and make such physiologi-
cal discomfiture rather rare.
The "Climatological Data" published monthly by the Weather Bu-
reau, U. S. Department of Commerce, recorded the following data for
the permanently maintained stations, over the period of 1841 to 1949:

TABLE 1.

CEDAR KEYS INVERNESS INGLIS (1942-1949)
Climatological Data
Year Data Year Data Year Data
Highest Rain........ 1912 83.40 inches 1937 70.98 inches ..................
Lowest Rain........ 1931 27.41 inches 1931 36.4 inches ..................
Average Rain........ 1841- 1901- 1942-
1949 47.25 inches 1949 54.53 inches 1949 45.68 inches
M in. Temperature ......... 15F...... ...... 14F........................
Max. Temperatures......... 1010F ........... 102F........................
Av. Jan. Temperature ...... 58.4F. ... ....... 58.5F.... ...... ...........
Av. July Temperature ...... 81.8F .......... 80.9F ....................
Growing Season ........... 314 days.......... 300 days.....................


The counties are heavily covered with vegetation, although much of
the high sand hill area has been stripped of the large pine forests that
originally covered it and is now covered by a thick screen of scrub oak
and young slash pine. Plains also have been largely stripped of vegeta-
tion and are farmed. These sand hills and some farm land have recently
been reconverted to slash pine planting, a source of income as pulp
wood. The coastal areas are choked with hardwoods, although most of
the large trees have been cut for timber. These swamps contain pine,






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


pond cypress, bald cypress, white cedar and red cedar of the conifers;
and tupelo, sweet gum, soft maple, sweet bay, cottonwood, willow, bass-
wood, southern magnolia, and yellow poplar, all of which are classified
as soft textured hardwoods. The hard textured hardwoods include oaks,
hickories, walnut, ash, river birch, elm, hackberry and sycamore.

CULTURE AND LAND UTILIZATION
County Names: Citrus County was created by the Legislature on June
2, 1887, and Levy on March 10, 1845 (Utley, 1908). Citrus was named
for the fruit and to indicate the abundance of these groves in the county
at the most northern latitude along the coast. Levy County was named
to honor David Levy Yulee who built "The Yulee Railroad", crossing the
county and connecting Cedar Keys with Fernandina, Nassau County.
Mr. Yulee was territorial delegate to Congress from Florida, and U. S.
Senator during 1841-61.
Population: Citrus and Levy counties are sparsely populated, the area
being largely utilized as cropland, pasture and woodland, but the total
population varied considerably from census to census, Levy more than
Citrus. The average population for the period 1900 to 1950 for Citrus
County is 5,811, and for Levy County 10,846. The peak year for Citrus
was in 1905 at 7,543 and for Levy it was in 1935 at 12,973. The low for
Citrus was in 1920 at 5,220, and for Levy in 1900 at 8,603. The 1950
population total for Citrus was 6,111 and for Levy it was 10,637.4
During the period 1900 to 1950, the Florida population increased
417.3 per cent, but that of Citrus County increased only 12.9 per cent,
and Levy County 23.5 per cent. The State population increased 44.1 per
cent during 1940-50, but Levy decreased 15.3 per cent and Citrus gained
only 4.8 per cent. These figures indicate that the counties are not being
settled or developed as rapidly as the remainder of the State, and con-
sequently the price of land is less than that in areas that are being
developed more rapidly.
The limited population centers are controlled by the industry sup-
porting the population, many being founded during the former greater
activity of the hard-rock phosphate mining industry. Towns are de-
veloped only along the valley of the Withlacoochee River, along bays
and fresh-water springs on the coast and on the plains that are developed
on top of Eocene limestones. Scattered timber growths, small farms and
4All figures on population are based on figures published by the Bureau of the
Census, U. S. Department of Commerce, and include news releases of the 1950 census.






FLORIDA GEOLOGICAL SURVEY BULLETIN 33


cattle grazing occupy most of the high sand hills. Lumbering, hunting
and fishing occupy the coastal lowlands and hammocks, and farming the
high limestone plains.

Land Utilization: The United States Census of Agriculture of 19455 in-
dicated the following land uses in Citrus and Levy counties:

TABLE 2.

Use Citrus Levy

Private Lands (acres)................................ 280,454.5 686,702.2
Farm s (num ber) ................................. 361.0 640.0
Croplands (acres) .............................. 19,543.0 81,277.0
Woodlands (acres) ........................... 110,928.0 131,447.0
Other (acres) .............................. 20,536.0 30,646.0
Public Service Corporations-
Railroads (acres) ............................ 1,654.0 1,825.0
Electric Light and Power Company (acres)...... 2,172.5 1,504.4
Unclassified (pasture, woodland?) (acres) ............ 125,621.0 440,002.8
Urban (acres) ..................................... 18,850.0 3,370.0
State and Federal (acres) ............................. 65,495.5 15,847.8

Total All Lands (acres) ............................... 364,800.0 705,920.0



In a series of news releases by the Division of Forest Economics of
the Southeastern Forest Experiment Station in cooperation with the
Florida Forest Service (June 1949, p. 26, November 1949, p. 26, Septem-
ber 1950, p. 8) the production of forest products in Citrus and Levy
counties were tabulated as follows:

TABLE 3.

Item Citrus Levy

Pulpwood production (standard cords) .................. 5,870 17,641
Lumber (thousands of board feet)-
Conifers (soft woods) .......................... 195,800 617,700
Soft textured hardwoods ........................ 76,200 86,400
Hard textured hardwoods. ....................... 21,400 96,000

Total all species ................................ 293,400 800,100


5U. S. Census of Agriculture, 1945, vol. 1, part 18, Florida. U. S. Department of
Commerce, Bureau of the Census, 1946, 162 pp.






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA 13


The U. S. Census of Agriculture of 19456 listed the following crops,
fruits, nuts, vegetables and stock as having been produced as primary
sources of income in these counties during the period of the Census:

TABLE 4.


Citrus Levy

Crops
Total value of all crops harvested (dollars) .............. 411,570 1,104,621
Corn (bushels)....................................... 20,493 152,377
Cowpeas (bushels) ................................... 1,265 3,161
Peanuts (nuts) (pounds): ............................. 6,110 1,662,043
Peanuts (hay) (tons) ................................. 340 1,107
Irish potatoes (bushels) .............................. 1,921 1,876
Sweet potatoes (bushels) .............................. 6,635 15,727
Sugarcane syrup (gallons) ........................... 9,365 40,059
Tobacco (pounds).................................... ............ 22,675
Chufas (nuts) (bushels) ........................................... 6,832
Tree Fruits, Nuts, Grapes
Value of all fruits and nuts harvested (dollars) ........... 246,015 92,617
Peaches (bushels).... .. ................. ........... 439 893
Grapes (pounds) ................................... 724 4,125
Pecans (pounds) .................................... 3,288 118,711
Tung nuts (pounds) ................................ 47,332 1,201,195
Oranges (field boxes) ............................... 102,241 305
Tangerines and Mandarins (field boxes)................. 11,492 ........
Grapefruit (field boxes) ............................. 14,921 ......
Lim es (pounds)..................................... 261 ......
Vegetables
Value of all vegetables sold (dollars) .................... 14,816 267,407
Stock
Value of livestock and products (dollars) ................ 247,820 694,146
Cattle (number) .................................... 11,593 27,790
H ogs (num ber) ..................................... 513 31,646
Goats and kids (number) ........................... 421 1,057
Chickens (number) .................................. 13,029 31,018
Turkeys (number) ................................. 649 7,664


From this tabulation it is apparent that the chief sources of farm
income in Levy County are peanuts, turkeys, cattle and hogs, sugar cane
syrup, tobacco, tung nuts and pecans, whereas Citrus derives its farm
income largely from citrus and stock raising. Watermelons were not
tabulated but they are an important cash crop in'Levy Cdunty, ranking
next to peanuts, and a minor Crop in Citrus County."

60p. cit., 1946.





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


PHYSIOGRAPHY

INTRODUCTION

Florida as it exists today is the land area of a much greater projection
of the Continent of North America which extends south to separate the
Atlantic Ocean from the Gulf of Mexico. This continental mass is the
east rim of the Gulf Basin, part of the west rim of the Atlantic basin and
about 60 per cent of it is covered by shallow marine water. The portion
covered is wider on the Gulf side than that on the Atlantic, the land area
and the submarine portion almost joining along the southern and.south-
eastern tip of Florida.
That portion of the continent covered by marine waters ranging out
from the shore line to a depth of about 300 feet of water is called the
Continental Shelf, and the range of elevations on it probably represents
the degree of change in sea level during the Pleistocene epoch, the shelf
being alternatingly above and below sea level during this time. Evi-
dence is rather conclusive that sea level during the Pleistocene occupied
levels considerably higher and lower than that of today.
This extension of the continent of North America, including both the
land area of Florida and the adjacent continental shelf was described by
Shaler (1890) and was named "The Floridian Plateau" by Vaughan
(1910). It projects out towards Cuba and almost joins a similar pro-
jection extending northeast from Central America, being separated from
it by deep water of the Yucatan Channel and from Cuba by the Florida
Strait.

GENERAL LAND FORMS OF FLORIDA

Fenneman (1932) placed the Floridian Plateau in the Coastal Plain
Province and land forms recognized within this province constitute sub-
divisions of it. Cooke (1939, p. 14, 1945, p. 8) in reports on the geology
of the State recognized a "Western Highlands", "Marianna Lowlands",
"Tallahassee Hills", "Central Highlands" and "Coastal Lowlands" to cover
significant land forms of Florida. Vernon (1942, p. 5) in an attempt toy
make the names of the topographic divisions in Holmes and Washington
counties descriptive of their origin used "River Valley Province" for
Cooke's "Marianna Lowlands"; "Coastal Plains Province" for Cooke's
"Western Highlands" and his "Coastal Lowlands". Wayne E. Moore, who
is preparing a report on the geology of Jackson County, has pointed out
the duplication of Fenneman's more comprehensive term and the unde-





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


sirability of continuing the use of the term "Coastal Plains Province" for
subdivisions of the physiography of the State.
Throughout most of western Florida, central Florida, southern Geor-
gia and southern Alabama a large delta plain (Vernon, 1942, p. 8),
made up of smaller coalescing subdelta plains (MacNeil, 1946, p. 60)
was formed during the interval extending from late Miocene to early
Pleistocene time. This plain is underlain by deposits placed in the
"Citronelle formation" by Cooke (1939) and in Plio-Pleistocene beds by
Vernon (1942).
During the Pleistocene these deltaic deposits were eroded and re-
deposited throughout several stages when sea level was alternately
lowered and raised by the development and subsequent melting of
glacial ice in high latitudes. A period of lowered sea level followed by
a period of raised sea level constituted a cycle composed of a period
of stream excavation and sub-aerial erosion followed by a period of
stream alluviation and marine planation and deposition.
Periods of raised sea level were of sufficient duration to cut low
seaward-facing embayed escalpments and to cut and construct broad
plains, the most recently formed still displaying bars and beach ridges,
and each being composed of a distinct depositional unit. Each marine
plain has a fluviatile equivalent that extends up the streams of Florida
as terraces that exhibit many characteristics of the Recent flood plains.
Assuming a net gain of land with the completion of each cycle, brought
about by one or more factors, including a progressive decreased deglaci-
ation from early to late Pleistocene stages and the eustatic adjustments
in land-sea relationships, a series of marine plains with seaward facing
escarpments would result, each plain extending up stream valleys as
flood plains and river terraces. T his combination of marine and fluviatile
agencies formed the greater part of the topography of Florida.
Five such cycles have been recognized in Florida by means of the
sediments and the terrace-surfaces that were formed (Vernon, 1942, p.
26), the deposits and surfaces of each cycle being preserved possibly
through uplift of Florida and by progressive smaller deglaciations
throughout the stages of the ileistocene. Five marine plains, including
the present sea bottom, have been formed which merge with five stream
surfaces, including the present flood plains, that are associated with the
streams that occupy Florida today.
Some areas of Florida were apparently sufficiently high in elevation
to extend through the blanket of plastic sediments formed by the delta






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


plain and by the stream and marine surfaces of Pleistocene age. Thus
some local ground surfaces are composed of weathered Tertiary rocks
and there is no younger sediment lying upon them.
The physiography of Florida can be grouped logically into four gen-
eral subdivisions on the basis of origin. Highlands are composed of either
sediments formed as a part of a high-level, widespread, aggradational
delta plain or of Tertiary land masses rising above this plain. Lowlands
have been formed either by deposition and erosion along coast lines by
marine agencies or by alluviation and stream erosion along stream valleys.
These obvious land forms can be grouped under four subdivisions of
the Coastal Plain Province, namely The Delta Plain Highlands, The
Tertiary Highlands, The Terraced Coastal Lowlands7 and The River
Valley Lowlands. These terms, applying to major subdivisions of the
physiography of the State, can be subdivided to any degree and local
names can be applied.
The Delta Plain Highlands, as thus proposed, would include Cooke's
"Western Highlands" and "Central Highlands" and the 250-320 foot sur-
face of Vernon's "Coastal Plains Province". The Tertiary Highlands
would include Cooke's "Tallahassee Hills" as a general term although
Tallahassee Tertiary Highlands would be appropriate as a local name.
The Terraced Coastal Lowlands would include Cooke's "Coastal Low-
lands" and part of Vernon's "Coastal Plains Province". The River Valley
Lowlands is equivalent to Vernon's "River Plains Province", and Cooke's
"Marianna Lowlands". The term "River Plains Province" (Vernon, 1942)
has been changed to River Valley Lowlands because "lowlands" is more
descriptive than "province", and some streams in Florida have not formed
alluvial plains although all occupy valley lowlands.

GEOLOGIC CONTROLS
The development of land forms in Citrus and Levy counties is con-
trolled by a warm, humid climate; high annual rainfall; a bedrock com-
posed essentially of carbonates that are easily soluble in fresh water
but highly resistant to marine erosion; low surface elevations; flat to
gently dipping porous rock, covered by limited porous sand and phos-
phatic beds; heavily charged phosphoric, humic and carbonic acid
waters; fracturing along the crest of the Ocala uplift and certain ground-
water conditions.

-Term proposed by W. E. Moore, manuscript of the Geology of Jackson County,
Florida.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Ground water is by far the most important agent altering the ground
surface and rocks of Citrus and Levy counties today, although in the
geologic past marine and fluviatile agencies were more important. In
spite of an average rainfall of fifty inches, surface streams and runoff
are ineffective in creating land forms in the counties. Thick sand cover
on all high hills, karst topography on plains, and swamps in lowlands
trap the large percentage of rainfall and result in heavy recharge to
ground water. This is true in spite of the two counties being part of a
discharge area for ground water contained in the system of artesian
water of Florida generally. Springs are abundant and each stream in
the area receives water from springs that empty from vents in the lime-
stone valley walls. This is true of all stream valleys except along the
upper reaches of the Waccasassa and Withlacoochee rivers where deep
fills of alluvium form a system of interconnected swamps that are fed
by ground-water seepage.

PHYSIOGRAPHY OF CITRUS AND LEVY COUNTIES

INTRODUCTION
Citrus and Levy counties compose a part of the Coastal Plain
Province, and the physiography is roughly subdivided into three major
units (see figure 2): 1) Tertiary Highlands; 2) Terraced Coastal Low-
lands; 3) River Valley Lowlands.
The Tertiary Highlands consist of limestone and clay hills formed
by the Suwannee and Ocala limestones and by the Hawthorn formation,
which extend above younger sediments and create a rugged topography.
The Terraced Coastal Lowlands in other parts of Florida consist of
four surfaces or plains that parallel the present coast. These plains are
bounded by erosional escarpments and each is underlain by a distinct
depositional unit. Marine deposits, such as bars, beach ridges, beach
escarpments and fossils in the lowest, characterize the surfaces and place
their origin within a marine environment. Vernon (1942, p. 18) recognized
in western Florida four surfaces having shore lines at 220, 150, 105,
and 30 feet above the present sea level. In peninsular Florida the two
lowest surfaces are present but the bases of the bounding escarpments
appear to be lower than they are in western Florida and the shore lines
are near 100 feet and 25 feet. The two higher surfaces, with shore lines
at 220 and 150 feet, have been so eroded in these counties that they
cannot be separated into distinct units, although deposits associated with
these surfaces are present.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Each of the two lower coastal surfaces includes a sandy beach de-
veloped along the coast line, and a limestone shelf cut by marine
planation, upon the youngest of which marine shells and late Pleisto-
cene sandy limestones were deposited.
The River Valley Lowlands include the limited narrow flood plains
developed at the mouth of each of the streams crossing the counties,
sand bars and alluvium deposited along the valley walls of the Suwannee
and Withlacoochee rivers during the late Pleistocene, and Tertiary lime-
stones exposed along the channels and valleys. The lower course'of
each valley has been recently entrenched into the limestone bedrock,
probably since the last rise in sea level. This entrenchment has formed
steep limestone-walled channels that end abruptly at the surface of each
coastal terrace.

TERTIARY HIGHLANDS
Within these two counties, the Tertiary Highlands are present only
in central Citrus County and because of limited exposures and a lack
of details their distribution is greatly generalized on the physiographic
map, figure 2. These highlands are erosional-remnant hills and ridges,
composed of the Suwannee and Ocala limestones, sand and clays of the
Alachua formation, and marine clays of the Hawthorn formation. North-
ward they merge with a high, rolling sand ridge that has been named]
the Coharie-Okefenokee Sand Ridge, page 25. In addition to the gen-
eralized mapping of the Tertiary Highlands in figure 2, they are also-
shown more specifically on Plate 1 as outcrops of the Suwannee lime-
stone and the Hawthorn formation.
The highlands rise steeply above the surrounding plains, figure 3, to
give an impression of relief considerably greater than the moderate re-
lief of 150 feet, which is present. The highest limestone hill on the high-
lands is 192 feet. Because this hill has no younger beds covering it and
early Pleistocene deposits are known to be present in the counties at
elevations up to 220 feet, it is presumed that the Tertiary Highlands
stood higher during the early Pleistocene and have since been reduced.

DELTA PLAIN HIGHLANDS
Although Cooke (1945, p. 9) mapped the "Central Highlands", equiv-
alent to the Delta Plain Highlands of this report, in Levy and Citrus
counties, no sediments similar to those found toward the east in the
Delta Plain Highlands of Lake and Polk counties or northward in
western Florida, were found. Also no elevation in the counties extends





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Figure 3. The Terraced Coastal Lowlands as seen from the Tertiary Highlands at
the Crystal River Rock Company quarry, five miles southeast of Crystal
River, Citrus County.

above 220 feet, which is the highest level of a definite Pleistocene shore
line in the State. Since the Pleistocene terrace surfaces, formed seaward
of the various shore lines, are aggradational (Vernon, 1942) and are
composed of formational units confined to each surface, it is apparent
that if the delta plain sediments ever extended across these counties
they have been reworked and deposited as early Pleistocene sediments.

TERRACED COASTAL LOWLANDS
These lowlands cover approximately 90 per cent of both counties,
and extend inland from the present shore to near the eastern extremities
of the counties, and may have extended over the whole area at one time.
Their continuity is broken only by lowlands developed along river valleys.
In other parts of Florida the Terraced Coastal Lowlands include four
coastwise surfaces, and deposits found beneath each of these are prob-
ably present in these counties, but because of erosion the two higher
surfaces could not be separated. Only the two lowest and youngest sur-
faces are well-developed and preserved. Deposits of the two oldest
surfaces make, in part, a high sand ridge which is named the "Coharie-
Okefenokee Sand Ridge". Tertiary rocks may compose a portion of this
ridge in Citrus and are the base of the ridge in Levy County.
The names of three coastal terraces as used by Cooke (1945) and
the term Okefenokee as used by McNeil (1949) have been applied to
the Pleistocene sediments in Citrus and Levy counties as follows:
The oldest and highest terrace is the Coharie with a shore line at 220






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


feet, the Okefenokee at 150 feet, the Wicomico at 100 feet, and the
Pamlico at 25 feet. These have characteristics in common with the
modern submarine plain at sea level. In the discussion that follows the
/modern plain and the youngest of the terraces are discussed first, the
details preserved upon these aiding in understanding older and more
--r-ed terraces.

Modern Submarine Plain
One attack on the problems in geology is to study the effects of
geologic agencies that are active today. Marine deposition and erosion
have controlled the formation of the coastal terraces that compose much
of the land surface of the State. In an attempt to understand the marine
plains of the Terraced Coastal Lowlands of these counties a study of
the modern submarine plain was made. This study was limited to the
evaluation of the submarine surface from hydrographic charts of the area,
from a series of core holes placed at one-half mile intervals, 13 miles into
Gulf waters by the U. S. Army Engineers along the route of the proposed
ship canal, and from three days of collecting submarine rock exposures
by diving and by sounding the bottom.
The sea bottom is a rolling plain sloping gently seaward and con-
taining irregularities caused by sand bars, oyster bars, limestone shelves
and reefs, and shell deposits. The submarine plain is composed of sev-
eral parts, these varying in width depending on the location of streams,
bay indentations and oceanic currents. Extending along a line drawn
perpendicular to the shore, this plain is made up of narrow bands of
sediment that parallel the modern coast line. Land along the entire
coast is rocky except in the vicinity of the Suwannee River, where it is
sandy. The rock is a fractured limestone and bays, inlets, islands and
rock pinnacles are common. Sandy mud marshes have penetrated along
the low places of the shore line, and the limestone stands above the
sediment in these marshes five to eight feet, making an abrupt escarp-
ment, see figure 4. This marsh averages two to three miles in width
except for southern Citrus County where it approaches six miles, see
figure 2. Extending out from shore and from the marshes there is a
submerged plain, varying considerably in width, that is composed of
two parts or belts. The coastal belt is covered by water that is very
shallow, only rarely exceeding four feet; sand bars are common and
make shoal areas. It is present from the shore out to where it ends, often
abruptly, in deeper water that covers the seaward belt of Tertiary
limestone that have been eroded to a rolling flat shelf. Depressions in
the limestone 'belt have been filled by deposits of modern shells of marine






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


mollusks and foraminifers, some of which have been loosely cemented
to form thin limestone beds. An occasional sand bar is present on the
shelf and some high areas of the limestone rise 10 to 20 feet above the
bottom as pinnacles.















Figure 4. Drowning of coastal margins by salt-water marsh. Photograph taken
facing due west at old Stevens Homestead, three miles northwest of
Yankeetown, Levy County. Islands in the marsh in the background are
composed of limestone of the Inglis member of the Moodys Branch
formation.

Coastal Terraces
The physiographic map, figure 2, and the aerial map, figure 5, reveal
two well-developed erosional escarpments across Citrus and Levy coun-
ties. These escarpments trend almost north and south and have been de-
veloped along the western foot of the Coharie-Okefenokee Sand Ridge.
They are the landward boundaries of two Pleistocene seas, the Pamlico
and Wicomico surfaces, with shore lines at 25 and 100 feet respectively.
Each shore line is marked by the development of a narrow belt of
sand along the coastal margins and further seaward by a broader belt
of limestone that has been planed by marine erosion to an irregular
rolling shelf. In these respects the Pleistocene surfaces correspond to
the modern submarine surface. The Pamlico surface has another charac-
teristic in common with the modern submarine plain which is the de-
velopment of fossiliferous marine sediments upon the limestone shelves.
Fossils have not been noted in the sediments of the Wicomico surface.
A high sand ridge, the Coharie-Okefenokee Sand Ridge, developed
to the east of the two definite Pleistocene surfaces covers most of eastern
Citrus and Levy counties. Remnants of this sand over the Williston






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Limestone Plain and in the Withlacoochee Valley indicate that the
ridge was once present over these areas and has been removed. This
ridge is underlain by the Alachua formation of Miocene (?) age and by
unfossiliferous sand and clay deposits of early Pleistocene age. In other
parts of Florida the Pleistocene deposits occur beneath two high sur-
faces occurring at definite levels, but evidences of the original surfaces
have been destroyed along this ridge.


Figure 5. Mosaic of aerial photographs of northern Levy County illustrating the
physiography and trace of the Long Pond Fault. Note the well-developed
terrace escarpments along the right side of the figure, and the offsetting
of the two blocks in the upper-left portion of the photograph.

Pamlico Terrace: This surface is well-developed in both counties and
is underlain by sediments that characterize the surface and compose
the Pamlico formation. The Pamlico formation is considered to be con-
temporaneous with sand bars developed along the Suwannee River at
comparable elevations.
The present coast of Citrus and Levy counties is obviously submerged,
as evidenced by the extensive coastal marsh, see figure 4, and the many
drowned valleys and inlets, Plate 1. This indicates a rising sea level that





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


is out of adjustment to the land mass. As a result, the Tertiary lime-
stones and younger beds that underlie coastal flat lands are being eroded
along coastal margins to form a fairly continuous limestone escarpment,
standing three to five feet above sea level. In the vicinity of the Suwan-
nee River, sand bars deposited by the river obscure the limestone es-
carpment and modern dunes, developed along the coast from Cedar
Keys to the Suwannee River, cover the Pamlico surface and create an
irregular ridge-like topography of Recent origin on a flat plain of Pleis-
tocene origin. This ridge, not separated on the physiographic map, figure
2, is included with the Pamlico surface.
The Pamlico marine plain, the lowest of the coastal terraces, extends
inland from the coast to approximately the 25-foot contour which marks
the foot of a 10 to 20-foot escarpment. The surface of the plain is about
eight to ten miles wide in Citrus County but covers most of central Levy
County, making a deep embayment along the Waccasassa River, where
it merges with a fluviatile equivalent developed as a small delta plain
at the mouth of a large stream that once occupied the valley, see pages
33 to 36.
The Pamlico surface is similar to the modern submarine plain in that
it is composed of long, narrow belts of sediment that parallel the Pamlico
coast line. A narrow band, up to three miles wide, extends seaward of
the Pamlico coast line and makes a distinct pattern on aerial photographs,
figure 5. This belt is composed of sand that makes a poorly drained flat
surface, covered by slash pine and palmetto. Elevations range between
15 and 25 feet although ridges that were apparently sand bars in the
Pamlico seas rise to slightly above 40 feet.
Toward the modern coast and seaward of the Pamlico coast line a
broad limestone shelf, up to 12 miles wide, composes the Pamlico sur-
face. This shelf lies near sea level at the modern shore line and rises
inland to an elevation of 20 feet. The Tertiary limestones, Avon Park
limestone, Moodys Branch formation, and Ocala limestone, have been
eroded by fresh-water and marine erosion to rolling flat limestone plains.
Irregularities produced by solution have been obliterated by a thin
covering of Pleistocene sediments of Pamlico age. These sediments in-
clude beach coquina deposits, brackish-water sediments, sandy unfos-
siliferous pasty limestones, fresh-water marls, and sand. Prior to this
coating of Pleistocene sediments the limestone surface was doubtless
made rugged with considerable relief, but the effect of the deposition
of these sediments has been to level this surface. In the vicinity of the
Suwannee River, sand bars have been deposited over the limestone by
the river.





FLORIDA GEOLOGICAL SURVEY BULLETIN 33


he lower coastal margins of the limestone shelf have been drowned
by salt-water marshes. Here the limestone extends as peninsulas and
islands into these marshes rising three to eight feet above the sediment
in the marsh. Along the Pamlico coast line the limestone shelf is covered
by the sand belt described above. The contact of sand on limestone is
distinct, being marked by a small definite depositional escarpment which
connects the gentle slopes developed upon the two belts.
Because the limestone shelf (see figure 6) is connected with the
artesian water system, the water levels in the ponds and lakes of the
coastal areas fluctuate greatly. During high seasonal rainfall the area
is flooded, ponds, lakes and streams coalescing to form a shallow swamp.
In periods of droughts most of the surface is dry and paved with rock
but the discharge from the aquifer maintains swamps in shallow basins.
This shelf is greatly fractured which, combined with the heavy discharge
from ground water, gives rise to numerous clear water springs scattered
throughout the hammocks. These are beautifully set in a tropical vegeta-
tion and are so located as to combine fresh water along the upper parts
and brackish water along the lower parts of the channels, and both
fresh- and salt-water species of fish inhabit some of the springs.
Virtually the entire belt of the Pamlico terrace, shown on figure 2
as limestone flatwoods and hammocks, is a continuous hammock, various
portions of which have been designated by the principal streams that


Figure 6. Limestone of the Inglis member forming the floor of the coastal ham-
mocks along State Road 55, U. S. 19, six miles north of Crystal River,
Citrus County





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


traverse them, such as Homosassa Hammock, Chassahowitzka Hammock
and Gulf Hammock developed about Waccasassa Bay. These hammocks
teem with game and fish and are valued as tourist attractions. Much of
the timber of Florida, cypress, cedar, pine, tupelo, gum, maple, bay,
cottonwood, willow, basswood, magnolia, poplar, oaks, hickories, wal-
nut, ash, birch, elm, sycamore, palm and tropical vegetation, grows in
such great abundance that the entire area is choked and virtually a
cancpy of vegetation is developed.
Wicomico Terrace: Like the Pamlico terrace and the modern submarine
plain, the Wicomico terrace is composed of a belt of sand developed
along the Wicomico shore line, and a submarine limestone shelf, named
the Chiefland Limestone Plain. The sand belt is developed along the
western foot of the Tertiary Highland and Coharie-Okefenokee Sand
Ridge. It enters Citrus County along its eastern central margin and
trends northerly to the vicinity of Bronson, Levy County, where it merges
with fluviatile sediments deposited along the valley of the Waccasassa
River. The belt is about two miles wide for the most part, but broadens
in southern Citrus County and up the valley of the Withlacoochee River.
The terrace is bounded on the east by an escarpment rising onto the
Coharie-Okefenokee Sand Ridge and to the west by the escarpment
of the Pamlico terrace. These escarpments and the terrace surface are
clearly evident on the aerial photograph of figure 5.
Chiefland Limestone Plain: The limestone shelf that is associated with
the Wicomico terrace is believed to have been preserved partly as -he
Chiefland Limestone Plain. In the vicinity of Chiefland a flat rolling sur-
face, figure 7, has been eroded upon Eocene limestones. The irregular
erosional surface has been leveled by the deposition of fine argillaceous
sand in the low places. Surface elevations range from about 40 feet at
Chiefland to about 80 feet near the Waccasassa Valley. The relations of
the elevations of the Wicomico limestone plain to its contemporaneous
sand belt is comparable to the distribution of elevations upon the sand
belt and limestone shelf of the Pamlico terrace and the modern sub-
marine plain.
Coharie-Okefenokee Sand Ridge: A high ridge of unfossiliferous sand,
having considerable relief, extends almost north and south across the
eastern portions of Citrus and Levy counties. The sand ridge merges
with and partly covers the high hills of Citrus County, which are com-
posed of Tertiary sediments. No consistent elevations or definite ter-
races were apparent, although elevations were generally higher on the
eastern side of the ridge. A maximum elevation of 220 feet was noted






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Figure 7. The Chiefland Limestone Plain northeast of Chiefland, Levy County, in
the center of Township 11 South, Range 15 East. Photograph taken
facing east.

on one hill in northern Citrus County. Here the sand covered the Su-
wannee limestone of Oligocene age.

The ridge is bounded to the west by the Wicomico terrace and its
fluviatile equivalent and to the east by the Williston Limestone Plain in
Levy County, and the Tsala Apopka Lake in Citrus County. The eastern
boundary is much more irregular, and remnants of the sediments com-
posing the ridge preserved on the lowlands along this boundary indi-
cates that the ridge probably extended over these lowlands and has been
removed.
The ridge is composed of Miocene (?) sediments of the Alachua
formation, covered by thick deposits of late Pleistocene sand. The sedi-
ments and fauna of the Alachua formation indicate that they were
formed under terrestrial conditions upon a very irregular limestone sur-
face eroded prior to their deposition and subsequently greatly altered
by the very erosive process of phosphate fixation, see pages 195 to 202.
Erosion by phosphoric and carbonic acids formed numerous sinks that
were partially filled by sediments of the Alachua formation.
Sands covering the irregular surface at elevations above 105 and
below 220 feet and the presence of Pleistocene surfaces with shore lines
at 150 and 220 feet throughout the State indicate that early Pleistocene
seas deposited a thick cover of clastics over a broad area throughout the
State. The greater portion of the sediments has been removed in these
counties leaving a high ridge, the ground surface of which is sand.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Phosphate fixation and the solution of limestone bedrock is continuing
today and the entire ridge is marked by slumps and sink holes, the
sediments forming the ridge being greatly distorted and the ground
surface made irregular.

RIVER VALLEY LOWLANDS
The River Valley Lowlands covers all stream valleys in the two
counties being found only along stream courses, and are very narrow
except for the specialized broad valley of the Withlacoochee River in
Citrus County and the Williston Limestone Plain in Levy County, a
part of the Waccasassa River Valley Lowland. These two valleys are
developed along the eastern portions of both counties, and lie east of
the Tertiary Highlands and the Coharie-Okefenokee Sand Ridge.

Stream Valleys
A number of sluggish clear water streams cross Citrus and Levy
counties, most of them flowing from high sand hill divides in a westerly
and southwesterly direction to the Gulf of Mexico. Only two originate
from outside the counties, the Suwannee River that borders the north-
western portion of Levy County and the Withlacoochee River that circles
Citrus County along the southeastern, eastern and northern boundaries.
The Waccasassa River, Otter Creek, Cow Creek, Ten' Mile Creek,
Turtle Creek and Wekiva River in Levy County; Crystal River, Halls
River, Homosassa River, and Chassahowitzka River in Citrus County,
are the larger streams of those originating within the counties. These
streams, as are the Suwannee and Withlacoochee rivers, are almost en-
tirely spring fed (see Vernon, 1947, p. 18), and all but three originate
in springheads. The Waccasassa River, Otter Creek, and Ten Mile
Creek flow in their upper courses over sandy soils and rise from swamps
and sinks as poorly defined and poorly connected channels that gradually
develop into definite stream courses. Their waters are heavily charged
with dissolved solids of surface origin, largely humic acids and organic
muds, and differ from the clear spring water of the other streams. In
the lower courses, their valleys are formed in limestone, the same as
other streams of the area.
Each of the streams originating in a springhead rises from caverns
that extend back into the limestone bedrock, and the upper portions of
many of the stream channels appear to be collapsed caverns. From the
springhead to the mouth each stream channel is formed in bedrock. These
streams, together with the larger Suwannee and Withlacoochee rivers,






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


flow throughout much of their length in limestone channels that are
broken by a maze of fractures and caverns, from which large flows of
ground water issue. Levy and Citrus counties are located in a discharge
area of the Florida artesian ground-water system.
Both counties have poor surface drainage, sand covered plains and
hills and karst topography capturing the large part of the surface waters.
Good surface drainage is present only along the coast, in central Levy
County, and along the valleys of the two major streams that cross the
area. Elsewhere ground-water drainage is predominate.

Stream Terrace Sediments
Stream terraces have been described in Florida by Vernon (1942)
and their origin discussed. In Citrus and Levy counties patches of al-
luvium lie along the valley walls of the Suwannee River and the Wac-
casassa River well above the flood plains. These sediments occur at two
definite levels and stream cut escarpments are present where the de-
posits are in contact. Each of the levels represent a period of alluviation
at a time when the streams were adjusted or were adjusting to sea levels,
higher than the present level.
The deposits that occur as sand bars along the Suwannee River Valley
are narrow and extend up the valley somewhat parallel to the present
flood plain. The bars have been well-preserved since their deposition
because of their great porosity and resistance to erosion by surface wash.
The deposits along the Waccasassa River are apparently unrelated to
the modern river system. The lowest of these deposits is a large valley
fill and delta that covers central Levy County at elevations from 20 to
50 feet above sea level. The valley is flat and gently sloping from its
upper portion to the center of the county where the stream deposits
merge with marine deposits of Pamlico age. The lower part of the valley
was probably a bay and sandy limestones of possible bay origin are
found interbedded with the alluvium. Alluvium is also preserved at
altitudes of 100 to 120 feet above the sea level, along the west side of
this valley, figure 2, covering a broad limestone plain in the vicinity of
Newton, Florida. These sediments are believed to be remnants of a flood
plain developed along a stream, larger than the Waccasassa River, that
once occupied and developed the valley the Waccasassa now occupies.
This flood plain occurs at levels comparable to the coastal terrace that is
a part of the Wicomico marine plain developed when sea level stood at
100 feet above modern sea levels.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Suwannee River Valley Lowland
The Suwannee River Valley, a narrow band of alluvium, thinly ve-
neering limestone bedrock except at the mouth where the fill of alluvium
is greater, extends along the northwestern boundary of Levy County. The
river empties into the Gulf of Mexico at Suwannee Bay where the lower
section of the valley is drowned and the flood plain is covered by salt-
water marsh. The river carries almost no sediment other than fine muds
and dissolved solids. During floods, fine to medium sand is reworked
along the river banks and dropped as sand bars along the valley walls.
Muds and dissolved solids are deposited along the lower reaches of the
valley at its mouth and in Suwannee Bay.

The valley of the Suwannee River is a solution valley and outcrops
of limestone are almost continuous throughout its length. Thin sand bar
ridges veneer the limestone bedrock away from the channel. This sand
occurs at two definite levels above the flood plain and the river is pre-
sumed to have occupied its present course since the late Pleistocene. If
sand bars of the Suwannee River were deposited during the early Pleis-
tocene they have either been removed by marine planation, or they
have been incorporated with other sediments from which they could not
be separated.

Withlacoochee River Valley Lowland
The Withlacoochee River rises in Polk County and for the most part,
throughout its course to the Gulf of Mexico, at Inglis, it flows on lime-
stone and through a limestone-walled channel. A flood plain is develop-
ed only along its course in Citrus County, above Dunnellon, Marion
County. From Dunnellon to the coast the channel is cut in limestone
and only a thin veneer of highly organic mud has been deposited along
its banks. Along this portion of the river the flats of the Terraced Coastal
Lowlands continue without a break to the edge of the channel walls, the
river having cut.a deep trench to the coast, modified by almost no al-
luviation. The mouth is drowned by Gulf waters and is marshy.

The river crosses the crest of the Ocala uplift in the vicinity of Dun-
nellon, and has had difficulty maintaining a course across it. The river
is clearly antecedent and the fold of the Ocala uplift has ponded the
river above Dunnellon to form the Tsala Apopka Lake. The valley be-
low Dunnellon is a limestone solution valley and where it crosses the
Coharie-Okefenokee Sand Ridge the banks are steep and the Alachua
formation and early Pleistocene sands make a deep V-shaped valley, con-






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


training a deep alluvial fill composed of sediments re-worked from the
Alachua formation and Pleistocene sand.
Tsala Apopka Lake: Tsala Apopka Lake is part of a rolling plain area,
up to 14 miles wide and 25 miles long, extending along both sides of the
Withlacoochee River and gradually merging up stream in Hernando
County with normal flood-plain topography. This plain is part of a
broad valley that is bounded by high sand hills to the southwest and
northeast. The northeastern (right) side of the valley is a broad swamp
broken by a few lakes, of which Lake Panasoffkee in Sumter County
is the largest. The southwestern (left) side of the valley is a system of
connected lakes, Tsala Apopka Lake, partially separated by rolling flat
peninsulas and islands.
The land surfaces are composed of Eocene limestones, over which
there is present a thin residuum of the Alachua formation, which ap-
parently was once of much greater extent, and largely has been removed
to form the valley. The land surface of the valley is one of considerable
relief, the low places being filled with water and the high places being
land, paved with limestone, predominantly the Inglis member of the
Moodys Branch formation. Phosphorite, clay and sand of the Alachua
formation thinly veneer the limestone and has filled fractures and sinks
to considerable depths. Near the river and along abandoned river courses
alluvium has been deposited, filling deep cut channels.
The water levels in lakes and swamps stand at elevations of 35 feet
in the lower, and 45 feet in the upper part of the valley. Land elevations
are commonly less than 60 feet but may rise to about 80 feet. The river
is a few feet lower than adjacent swamp and lake levels in the lower
part of the valley, but in the upper part the channel of the river is not
clearly distinguishable from swamp and lake. The river meanders tor-
turously through the upper Tsala Apopka Lake, the channel often being
recognized only by relatively unobstructed water passing through dense
cypress and other water growths. Where the channel is obstructed by
hyacinths it is exceptionally difficult to locate and it is almost impossible
to traverse the river. Numerous tributaries, the Panasoffkee River, Juni-
per Creek, Dead River and smaller streams contribute to the compli-
cated pattern of channel crossings through the lake.
From a study of the stream patterns and the geology along the
Withlacoochee River, it is evident that the river is antecedent, at least
in part, to movements forming the Ocala uplift. The course of the With-
lacoochee River, for the most part, is along the top of the Ocala uplift.
It apparently has adjusted to the fractures developed along the crest





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


of the uplift, the course of the river paralleling the fracture pattern of the
area, see figure 11. In the vicinity of Dunnellon the river departs from this
pattern and heads westerly toward the Gulf of Mexico. This course is
across the crest of the Ocala uplift and the river has cut a deep lime-
stone-walled channel to the coast. The most striking feature of the upper
Withlacoochee River is that the stream channel is not formed continu-
ously in bedrock as it is toward the coast, instead deep alluvial fills more
than 100 feet thick, reaching depths to 83 feet below sea level are present,
see well W-1198 of figure 14.
This information indicates that the river was established along its
present course by erosion of a deep valley cut into the Alachua forma-
tion and Eocene limestones. The river has meandered across its valley
along the east flank of the Ocala uplift and has eroded a broad valley
and filled it with alluvium. This ponded water has accelerated ground-
water recharge to the underlying limestone bedrock. Solution of the
limestone has created depressions throughout the valley, and these, to-
gether with flood plain lowlands, form the basins of the many lakes that
occupy the valley.
There is no evidence of either erosion or deposition that indicates
the river has occupied its position for any great time. Its valley is steep
and V-shaped where it crosses the Coharie-Okefenokee Sand Ridge and
no high level river terrace deposits are found along its valley walls, which
suggests that the river was established during the late Pleistocene. If
this is true, periodic structural movements along the Ocala uplift must
have continued into the Pleistocene, although there is evidence that the
major movement was during the Miocene.
Matson (1913, pp. 33, 34) used the name Tsala Apopka Terrace for
a marine terrace surface lying between elevations of 40 and 60 feet, in
the vicinity of Tsala Apopka Lake. In view of the evidence developed
during the study of Citrus and Levy counties this surface is clearly
fluviatile in origin and the abandonment of the name as a physiographic
term by other writers is substantiated.

Waccasassa River Valley Lowland
The Waccasassa River rises as a poorly defined channel connecting
swamps and tyty ponds in Gilchrist County. Along its upper course in
Levy County the stream is a sluggish, poorly connected series of swamps,
lakes and ponds that have formed in a valley up to three and one-half
miles wide, see figures 8 and 9. Approximately two miles south of New-
ton, Levy County, this valley fans out, and one side extends westerly






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


toward Long Pond and breaches the Chiefland Limestone Plain at this
point. The other continues southerly along the foot of the Coharie-Oke-
fenokee Sand Ridge. The pattern of this widened valley and the sedi-
ments that underlie the flat surface exhibit characteristics of an alluvial
plain, see figure 2. The limestone bedrock is buried 14 to 18 feet beneath
cross-bedded sands and clays throughout the area.













Figure 8. Broad lake-filled valley now occupied and only partially drained by the
Waccasassa River. Photograph taken facing south in Section 13, Township
11 South, Range 16 East.

From the point where State Road No. 34 crosses the river to the
coast the river flows through a limestone-walled channel that is a trench
cut by the river into the flat surfaces of the Terraced Coastal Lowlands
and of the alluvial valley described above. Throughout its lower course
the river is spring fed and has all the characteristics of other streams of
the area. A modern narrow flood plain of organic muds and sand is
present only in the lower portion where the river merges with the
marshes formed by drowning of the mouth of the river.
In northern Levy County, northeast of Newton, the Eocene lime-
stones are covered by a thin deposit of alluvium containing Pleistocene
sands and sediment reworked from the Alachua formation, see figure 2,
and limestone exposures are rare. This alluvium lies at an average eleva-
tion of 110 feet and is believed to have been deposited by a stream larger
than the Waccasassa, see pages 33 and 36, that occupied the valley dur-
ing Wicomico time when sea level stood at 100 feet, and the Chiefland
Limestone Plain was a marine shelf.
Williston Limestone Plain: Over most of eastern Levy County, particu-
larly in the vicinity of Williston where it is well-developed, there is a
gently rolling limestone plain. Exposures of Eocene limestones are com-
mon and only a thin veneer of sand and residuum of the Alachua forma-






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


tion covers the bedrock. Pockets of phosphate of the Alachua formation,
preserved upon this plain, were the sites of the early hard-rock phosphate
mines in the area. The plain ranges in elevations from 60 to 80 feet with
an occasional knoll rising to 100 feet. Shallow prairies, sinks and lakes
mark its surface irregularly.
The plain has very irregular boundaries, being bound to the west
by the Coharie-Okefenokee Sand Ridge and to the east by high sand
hills composed of sediments similar to those of the Coharie-Okefenokee
Sand Ridge. The plain is about 10 miles across at its widest and extends
east and south into Marion County, narrowing and branching to the
south. Toward the north in Alachua County the plain widens and branch-
es to include Payne Prairie, other large prairies, lakes and much of the
Arredondo quadrangle. The plain can be traced across the western
portion of Alachua County into Gilchrist County where it joins the
broad valley now occupied by Cow Creek and Waccasassa River.
In its pattern, sediments and physiography, this broad plain resembles
the Tsala Apopka Lake region and is believed to have had a similar
origin, to have been occupied once by a well-developed stream or stream
system. This stream emptied westward into the Waccasassa River Valley
Lowland prior to stream capture in that valley. Prairie Creek now empty-
ing into Payne Prairie may have been this stream, which was captured
by underground drainage. Its tributaries meandering down the eastern
slope of the Ocala uplift could have removed in early Pleistocene time
the unconsolidated sediments that covered the Tertiary limestone.

Stream Capture
The broad and shallow valley present in northern and central Levy
County that is occupied now by the Waccasassa River contains no defi-
nite and significant streams for the most part, and the width of the valley
does not correspond to the size of the streams that occupy it, see figure 8.
On the aerial photograph, figure 9, this valley can be traced from central
Levy County across Gilchrist County to the Santa Fe River where it ends.
The valley trends almost due north and south being slightly concave
toward the east; and is bounded to the west by good farm land develop-
ed upon the undulating Ocala limestone plains and to the east by high
sand hills composed of the Alachua formation and Pleistocene terrace
sands.
The valley is flat and sandy and contains a maze of small prairies,
tyty ponds, and small open lakes. Much of the valley is now drained
underground by sinks and during heavy rainfall many of the swamps,






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


t
L-
h
1~
Pik~d~: ;~~


c-^


jIltZ;U~ Y~


Figure 9. Aerial photograph of a broad, poorly drained valley crossing Gilchrist
County into northern Levy County.


;I

iA ]L~.:R~


JCfh


~ .F3~~


~F~a~





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


prairies and lakes are connected. Some of the prairies and swamps are
arcuate and enclosed and resemble old meander scars in pattern and
distribution. This is particularly true in the vicinity of Franklin Sink, Gil-
christ County.
The valley is drained in the north by Cow Creek and in the south by
Waccasassa River and, for the most part, is not occupied by any definite
continuous drainage. The two streams that drain the extremities of the
valley are sluggish and swampy and are too small to have formed such
a broad valley. It is presumed that the valley was once occupied by a
large stream which has been beheaded by stream capture in the vicinity
of its juncture with the Santa Fe River Valley, or that the stream may
have been captured by underground drainage.
Stream capture and water diversion is not uncommon to the north
in Columbia County, several dry stream valleys, such as Long Arm Ham-
mock, being present.8 Likewise numerous collapsed-cavern water courses
which connect between natural bridges are present in the county. These
are prominent on aerial photographs of Columbia County, the Itchtuck-
nee River and Olustee Creek with their subterranean connections being
good examples.
The presence of confirmed dry stream courses in Columbia County
suggests the possibility of stream capture in adjacent counties. Cow
Creek is separated by an almost imperceptible divide from the swamps
forming the headwaters of Waccasassa River, and its course is more
clearly defined than that of the river indicating a higher gradient in
Cow Creek, presumably the reversed portion of a larger stream with
the Waccasassa River being the beheaded remnant. Cow Creek is also
most peculiar in that it has a northerly course, whereas most streams
of the area run south and southwest toward the coast. Each of these
facts considered together indicate stream capture, but the valley may
have resulted from the modification of a Pleistocene marine terrace and
escarpment, since such a terrace and escarpment is known to be present
along the east side of the valley. It is believed, however, from a study
of the character and distribution of sediments of northern Levy County
that once a large stream formed a delta (shown in figure 2) that ex-
tended over much of central Levy County forming a thin veneer of
plastics on limestone bedrock. These sediments are cross-bedded sands
and clays containing elements of the Alachua formation, presumably
eroded from the eastern side of the valley along the base of the escarp-
ment rising onto the Coharie-Okefenokee Sand Ridge of eastern Gil-
SPersonal communication from J. C. Simpson, February 7, 1951.






FLORIDA GEOLOGICAL SURVEY BULLETIN 33


christ and Levy counties. This stream was probably the ancestor of the
Waccasassa River, which remains as a sluggish stream, occupying a
portion of a broad valley, largely abandoned.
The stream capture is dated by the Pleistocene history and sediments.
The alluvium along the Waccasassa River merges with marine deposits
of the Pamlico and Wicomico formations. A major stream obviously oc-
cupied the valley during Pamlico time when sea level stood at 25 feet.
This is the youngest coast line in the area and is believed to be late
Pleistocene in age. The stream capture probably occurred during en-
trenchment of streams into the limestone bedrock following the uplift
of the land during the late Pleistocene and the last rise in sea level. If
this premise is true, the date of capture would be early Recent.


PLEISTOCENE HISTORY IN FLORIDA

TERRACED COASTAL LOWLANDS
Many studies have been made and numerous publications covering
terraces in Florida have been printed. The major contributions on ter-
race studies were summarized by Vernon (1942, pp. 15-18). From these
studies two basic theories of terrace origin within the State have been
developed. One theory proposes that these terr-pc are sentially marine
planation surfaces cut during cyclic eustatic and permanent lowering
sea levels throughout the Pleistocene epoch. These surfaces were cut
into older ertiary beds and a widely developed bed of elastic sedi-
ments, named the Citronelle formation of Pliocene age. In part these
cut surfaces are thinly veneered by as much as 50 feet of reworked
elastic and other sediments. In the mouths of streams that emptied along
the coast of each marine surface, limited deltaic deposits were formed.
According to this theory the terraces are preserved because sea levels
rising during interglacial stages never reached the position of an older
stand of the sea and younger surfaces were cut at lower elevations. The
progressive decrease in the elevations of sea levels throughout the stages
of the Pleistocene resulted from greater deglaciation during early Pleis-
tocene than during late. Additional stands of sea level were produced
by the development of large oceanic deeps at various irregular intervals
during the Pleistocene. 'ihe formation of these deeps enlarged the
oceanic basins and decreased sea levels throughout the world.
Cooke (1939, 1945, pp. 12, 13) is the principal proponent of this
theory and has described up to nine surfaces, including the modern





GEOLOGY OF'CITRUS AND LEVY COUNTIES, FLORIDA


submarine plain, that occur throughout the Atlantic and Gulf Coast
States.
Four similar terrace surfaces occurring along the central Gulf Coast
States have been described by Fisk (1938, 1940). These are stream ter-
races, the coastal ends of which are widely-developed deltaic plains.
Each terrace.surface is aggradational and underlain by sediments that
are characteristic of the terrace, being a depositional sequence of coarse
plastics at the base and finer plastics at the top. This theory of terrace
origin presents evidence that the surfaces are deposited as deltas and as
alluvium in erosional valleys, each terrace being comparable to the
present delta plains and flood plains of Louisiana today. Terraces were
formed by adjustments of streams and coasts to eustatic changes in sea
level resulting from cyclic withdrawals from and filling of oceanic basins
during stages of the Pleistocene. Glacial stages were periods of lowered
sea level, valley cutting and broader land areas. Interglacial stages were
periods of elevated sea level, valley alluviation and flooding of land
areas. Each terrace has been segregated by the tilting and uplift of the
land adjusting to the extensive sedimentation of the Gulf of Mexico.
Evidence presented by Vernon (1942) and developed during the
study of the physiography of Citrus and Levy counties does not allow
the complete application of either theory in Florida. The topography of
Florida is dominated by a series of uplifted broad flat surfaces that rise
in step-like patterns from the coast inland to highlands composed of
Tertiary and younger deltaic sediments. These flat surfaces or plains
occur in four belts that extend completely around the State parallel to
the modern coast. Each plain has a fluviatile 'terrace extension up the
major streams of western Florida and sand bar deposits occur at com-
parable elevations along the streams of the Peninsula. Each uplifted
plain contains upon it features of the modern submarine plain, and its
fluviatile extension has features that characterize the modern stream
flood plain and deposits, all in varying degrees of preservation.
The marine plains and fluviatile equivalents are separated by erosion-
al escarpments and are considered to be terraces.
In Florida, auger holes and wells penetrating the Pleistocene deposits
that underlie the terraces, indicate that the base of each rests upon an
erosional surface, which lies at a lower elevation than similar cut sur-
faces, older in age. Each terrace surface is aggradational, except where
Tertiary limestones have resisted erosion and have been planed off to
the level corresponding to the elevation that the sea stood during the
creation of the terrace. In western and most of peninsular Florida, where






FLORIDA GEOLOGICAL SURVEY BULLETIN 33


abundant sediments were available and where the Tertiary formations
were easily eroded, each surface is underlain by its unit formation.
In Citrus, Levy and adjacent counties, however, the Tertiary limestones
were not eroded and each surface is made up of belts of beach sedi-
ments and limestone planation shelves that contain in irregularities in
the limestone, thin deposits of Pleistocene sediments. Along the most
southern portion of Florida these Pleistocene terraces are represented by
marine limestones and the erosional escarpments that bound each ter-
race are represented by fresh-water marls.
The terraces are thought to have been segregated by uplift of the
State caused by adjustments to the filling of the Gulf by sediment, and
through the progressive decrease in deglaciation from early to late
Pleistocene.
The creation of the fluviatile terraces of Florida can be explained
most easily by Fisk's valley cutting and subsequent alluviation theory,
with the exception that there is present a high level delta plain, entirely
disassociated with the streams that traverse the State, and there is present
a very low alluvial terrace (Vernon, 1942, pp. 13, 14) which is not
recognized by Fisk9. He recognizes, however, a low escarpment-bound,
alluvial surface which has been referred to in Louisiana as "second
bottoms" or "high level flood plains". It would seem logical that the
same geologic controls and conditions creating Fisk's higher terraces
would also most easily explain the formation of this low terrace.
Cooke, in a series of papers, has recognized nine terraces, one of
which is covered by the modern sea, and one which he has not named10
and which corresponds to the Okefenokee Terrace of this report. Only
four of these terraces are widely developed in Florida, and this writer
has seen no evidence of a general development of terraces with shore
lines at 270, 170, 70, and 42 feet. If these terraces of Florida were formed
through the cyclic eustatic adjustments in sea level throughout the
Pleistocene, a period of stream and sub-aerial erosion followed by a
period of fluviatile and marine deposition, each marine terrace should
have a fluviatile extension up the streams of Florida. Only four stream
terraces are present and these merge with coastal terraces associated
with former coast lines at 220, 150, 100 to 105, and 25 to 30 feet above
the present sea level.
According to Cooke11 additional terraces were formed over the states
9Personal communication, 1939.
10Personal communication, 1942.
11Personal communication, 1942.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


of the southeast where sea level was lowered by irregular increases in
the size of oceanic basins through the formation of deeps. There is no
evidence of deep valley erosion along the streams of the Gulf Coast that
would indicate stream adjustment to a permanently lowered sea level.
Five erosional sub-valleys compose each of the modern stream valleys in
the State, each of these sub-valleys in succession having been cut and
then filled to form four terraces and a flood plain along the modern
valley.
By definition, a terrace is a flat surface, either deposited upon or cut
into bedrock, that is limited by definite escarpments. These surfaces and
escarpments, because of destruction by erosion and of the development
of slopes instead of escarpments along some bays, can not be uniformly
and continuously present. However, they must be present throughout
the State at intervals sufficiently frequent to establish their identity.
For each coastal terrace there would be developed in the valleys of
principal streams of the State a fluviatile terrace equivalent. Theoretic-
ally, the sea as it withdrew from off the land during a glacial stage stood
for brief periods at all elevations from the position of its highest shore
line to the position of its lowest shore line, located somewhere out on the
continental shelf. The withdrawal of any of the Pleistocene seas was
controlled by climatic conditions and brief periods of warmer climate
during any glacial period may have stabilized sea withdrawals momen-
tarily and allowed some reworking of sediments and deposition of sand
bars sufficient to create some minor features which may have been in-
terpreted as terraces. These features have no fluviatile depositional
equivalents and are not universally developed as are the four terraces
generally recognized by most workers.
Minor terraces such as Cooke's Sunderland, Talbot and Penholoway,
which are not present in any area worked in detail by the writer, possibly
represent temporary pauses by the sea in withdrawing from the land
mass. The writer does not consider these to be representative of a cyclic
period of erosion and fill, and therefore not terraces as used in this
report.
The four Pleistocene terraces, composed of a marine plain and a
fluviatile equivalent, together with a highlands delta plain as recognized
by Vernon (1942) are shown in Table 5, with possible correlations of
seven of Cooke's (1945) terraces and his Citronelle formation and of
Fisk's four delta plains and his "high level flood plain and second
bottoms". The terms Pamlico, Wicomico and Coharie have been used
in this report for levels and deposits present in Citrus and Levy counties







TABLE 5.-Correlations of Pleistocene Terraces


Fisk, 1940

Williana


Valley erosion

Bentley

Valley erosion

Montgomery

Valley erosion

Prairie


Valley erosion

Second bottoms and high
level flood plains

Valley erosion

Modern delta


Cooke, 1945
(Elevations of shore lines in feet)

Citronelle fm.
Brandywine, 270




Coharie, 215




Sunderland, 170



Wicomico, 100
Penholoway, 70
Talbot, 42



Pamlico, 25





Modern submarine plain


Western Florida
Vernon, 1942
(Elevations of shore lines in feet)

Delta plain


Valley and sub-aerial erosion

220

Valley and sub-aerial erosion

150

Valley and sub-aerial erosion

105


Valley and sub-aerial erosion

30


Valley and sub-aerial erosion

Sea level


Citrus and
Levy Counties, Florida
Vernon, 1951

Not present


Valley and sub-aerial erosion

Deposits of Coharie, 220

Valley and sub-aerial erosion

Deposits of Okefenokee, 150

Valley and sub-aerial erosion

Wicomico, 100


Valley and sub-aerial erosion

Pamlico, 25


Valley and sub-aerial erosion

Modern submarine plain
and stream food plains


Tentative Age Assignment
of Terraces in Florida

Early Nebraskan and pos-
sibly pre-Nebraskan

Nebraskan (glacial)

Aftonian interglaciall)

Kansan (glacial)

Yarmouth interglaciall)

Illinoian (glacial)

Sangamon interglaciall)


Glacial stage

S Interglacial stage


Glacial stage

Recent interglaciall)





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


at elevations comparable to those of Cooke. However, since Cooke
recognizes no terrace at 150 feet, the term Okefenokee is preferred as
used by MacNeil (1949) as a name for the terrace in Florida with levels
below 150 feet.

STREAM VALLEYS IN WESTERN FLORIDA
In western Florida each of the stream valleys is composed of a series
of uplifted flat surfaces that border the present flood plain and extend
up stream valleys in step-like discontinuous patterns. These surfaces have
been interpreted as the former flood-plain alluviation of valleys cut into
older alluvium and Tertiary rock by the stream now occupying the valley
(Vernon, 1942). Detailed work has proved that each of these surfaces
is underlain by a definite depositional sequence, from coarse sand and
gravel at the base to silts and clays at the top, and that each has present
upon it features of modern flood-plain deposition such as natural levees
and rim swamps.
The origin of such alluvial surfaces as a combination of cyclic Pleis-
tocene eustatic changes in sea level and uplift was proposed by Fisk
(1938) for Louisiana and was extended to Florida by Vernon (1942)
with the application of the theory of progressive decreased deglaciation
throughout the Pleistocene. Thus valleys cut during low sea level glacial
stages were filled with alluvium as sea level rose with the melting of
glacial ice during the interglacial stages. The continuous uplift of Florida
throughout the Pleistocene that has progressively raised and separated
these terraces, is presumed to be associated with the thick alluviation of
the Gulf of Mexico, principally by the Mississippi River, and adjustment
to this alluviation. Uplift does not account for the separation of the lower
terraces, however, because these surfaces would be covered by alluvia-
tion if all the ice on polar caps should melt. It is presumed that more ice
melted during the stages of the early Pleistocene than during the stages
of late Pleistocene.
The modern flood plain and four depositional surfaces are associated
with each major stream in western Florida. Each alluvial surface ends
on a broad flat plain that extends all around Florida, the modern flood
plain ending on th- mouern submarine plain and each alluvial terrace
ending on a coastwise surface exhibiting marine characteristics.

STREAM VALLEYS IN CITRUS AND LEVY COUNTIES
Marine coastwise surfaces are present across Citrus and Levy counties,
but alluvial surfaces are not present. At the elevations that alluvial






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


terraces are found in western Florida, only sand bar ridges have been
deposited in the Citrus-Levy County area.
The bedrock of the area is essentially carbonates, greatly fractured
and cut by caverns. The amount of dissolved solids in ground water
indicates that the limestone is being continuously reduced by solution in
surface and subsurface waters. During stages of the Pleistocene when
sea level dropped, and streams in western Florida were excavating their
valleys, the streams of these counties found it easier to drain through
fractures and caverns into the underlying bedrock and did not excavate
deep valleys. Subsequently as sea level rose during the interglacial stages,
the limited sediment available to these streams was deposited in Levy and
Citrus counties as sand bars, and the streams adjusted their channels to
the uplift of the area through accelerated solution to form limestone-
walled channels. In effect no valleys were cut during glacial stages to be
filled by sediment during interglacial stages of the Pleistocene so that
terraces have not been formed.

KEYS
The word Key is a modification of the West Indian word cayo,
meaning small low island, and is used in southern Florida for an island
of any rock composition in marine waters. In Citrus and Levy counties
these keys are composed of limestone thinly coated with sand or they
may be essentially sand. Most of the keys of Cedar Keys and north to
the Suwannee Rivet are sand islands, the sand probably being reworked
into bars and spits from deposition made by the river along its lower
course.
The keys of the coast south of Cedar Keys are limestone islands, the
entire coast being rocky. Islands are remnants and pinnacles of lime-
stone, left after solution, which have been drowned by salt-water
marshes. None of these are coral reefs, as found along the Florida coast
to the south.
Tidal passes up to 15 miles long, and deep enough to traverse in
shallow draft boats wind past the islands and connect the Gulf with
spring fed streams emptying along the coast line.

SOLUTION
INTRODUCTION
Citrus and Levy counties are underlain by limestone and other
calcareous deposits. Except for the portion covered by the Coharie-





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Okefenokee Sand Ridge these deposits lie at or near the ground surface.
The bedrock is greatly fractured and very porous and almost all the
rain that falls in the area is absorbed by loose sand or is captured by
solution holes and the fractured porous bedrock. These waters are highly
charged with organic and carbonic acids and solution plays a conspicuous
role in the development of the physiography of the area. The ground
water that passes through these carbonates to emerge as springs or seeps
carries in solution great quantities of mineral solids, since limestone is
readily dissolved in organic and mineral acids contained in water.

CAVERNS
Limestone is as a rule jointed vertically and bedded horizontally and
openings along these joints and beds provide easy avenues of travel for
water. The ultimate source of all of Florida's ground water is from the
rain and precipitates from the atmosphere. As the rain water falls through
the air it becomes charged with carbon dioxide gas that combines with
water to form carbonic acid. On the ground humic acids from rotting
vegetation is added. These are the common natural solvents of limestone.
A good portion of this acid charged water soaks into the ground, and as
it descends small portions of the rock are dissolved, but where the rock
is saturated and bathed continuously in these weak acids, solution is
most active. Because of the pressure of water entering the rock, ground
water tends to move horizontally along bedding planes which offer the
easiest exit. As it moves through pores and open spaces in the limestone
it acts as a slow solvent to increase the size of the openings and to
connect them to form a continuous system of channels. As these channels
are expanded by solution, cave systems are developed horizontally and
one system may lie over another and may be connected by vertical tubes
and rooms.
These solution holes are formed principally while the limestone is
saturated by ground water. Since many large caves and vertical tubes,
now completely dry, are present west of Long Pond, south of Newton in
Levy County and in the vicinity of LeCanto in Citrus County, it is
obvious that the levels of ground water have been lowered over most
of the area. The remains of land vertebrates of Pleistocene, Pliocene and
Miocene ages (see pages 184, 192 and 212) that are found in deposits in
the caves indicate that many were dry during at least some stages of these
epochs. These caves are now being modified through the deposition of
calcite along the walls and floors, to form icicle-shaped masses called
stalactites that hang from the ceilings and more columnar masses called





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


stalagmites that extend upward from the floor, and pavement coatings
along many of the walls.
SINKS
As solution progresses, cavities of irregular shape are gradually cut
out and enlarged. Some of these may expand to a point near the ground
surface where surface deposits, largely sand in Florida, will collapse into
the cavern and a sink hole is formed. The larger part of Florida's natural
lakes, sinks, depressions and ponds are the result of the solution of lime-
stone. The features range from small pits a few feet in diameter to large
depressions several miles broad. Many are perfectly round, others highly
irregular. Some are cone-shaped with rocky bottoms and walls, some
have broadly-developed, sediment-filled flat bottoms and are known as
prairies. Still others are vertical tubes, only a few inches in diameter in
some cases, that extend as much as 100 feet down into the limestones.
These are "natural wells", or solution pipes.
As Vernon (1947) has indicated, the generally accepted theses of the
solution of limestone rarely include a conception of the effect of artesian
water upon soluble aquifers such as limestone. Citrus and Levy counties
are a part of a large artesian ground-water system, in which water gains
entrance into a thick limestone aquifer in areas centered at Polk and at
Pasco counties. The water is confined in these limestones under hydro-
static head and discharges in Citrus, Levy and other coastal counties.
This water is heavily charged with natural acids and the active circula-
tion through the aquifer removes large tonnages of rock. The solution
holes thus formed are filled with water and where they emerge at the
ground surface springs and seeps of water issue from them. Since artesian
water is under pressure it tends to expand upward along joints and more
soluble rock because of greater porosity toward the ground surface. The
localization of this movement vertically may explain the formation of
solution pipes and "natural wells", see figure 10. Where solution by
artesian water removes a large section of limestone the overlying beds
may collapse and create a sink hole, or the solution of the limestone may
be more gradual and a spring opening may be expanded to the pro-
portions of a sink.

LAKES
Lakes in Citrus and Levy counties are largely water-filled solution
depressions except for Tsala Apopka Lake and Long Pond, the basins
of which originated as structural and fluviatile irregularities and were
modified by solution. Water to fill the lake basins comes from local






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Figure 10. Solution pipe formed in the Ocala limestone (restricted) and bisected
by the Levy Lime Rock Company quarry located at the Atlantic Coast
Line Railroad in the southeast corner of Section 19, Township 12 South,
Range 19 East. The clay filling has been washed out and deposited as
a cone at the base of the quarry face.


rainfall, local ground water, artesian ground water or a combination of
these sources. Where the basin intersects the artesian aquifer, water will
fill the basin to the elevation of the static water levels, and will flow if
the rim of the basin is below the piezometric surface. Where the surface
of the ground and the ground-water levels are approximately the same
elevation, swamps are present along the low areas, and if this relation-
ship is present in a basin, a prairie is formed.






FLORIDA GEOLOGICAL SURVEY- BULLETIN 33


Many of the lake basins are located at the foot of Pleistocene escarp-
ments along which irregularities localize the ground-water recharge and
accelerate solution. Others are close to and are developed along well-
developed fractures in the underlying limestone that provide channels
for ground-water movement. In addition to physiographic irregularities,
those created by structural movement also localize ground-water
recharge.
Long Pond: The basin of Long Pond is of particular interest since it was
formed by a combination of solution, structural movements, and Pleis-
tocene erosion and deposition. The lake is located one mile south of
Chiefland, Florida, in sections 7, 16 and 19, Township 12 South, Range
13 East, and is a slightly arcuate lake, two and one-third miles long and
one-quarter mile wide. It lies along the western margin of the Wacca-
sassa River delta plain that composes a portion of the Pamlico Terrace.
The lake is bound to the west by limestones of the Moodys Branch
formation exposed along the upthrown side of a fault that passes through
the lake and makes a high escarpment along the western margin.
The lake basin extends along the foot of the escarpment to near the
north end of the lake where a well-developed valley branches off and
runs westerly toward the Suwannee River widening as it nears the river.
This valley is walled with limestone but the floor is composed of a fill
of sand and reworked Alachua sediments similar in lithology to that
contained in the delta plains to the east. The sediments in the valley and
brackish water deposits along the lake basin of Long Pond indicate that
the area about the lake was a bay during Pamlico time, and that this
bay was filled by alluvium deposited from the east by a large stream
once occupying the Waccasassa River valley. The valley draining wes-
terly from Long Pond and breaching the Chiefland Limestone Plain
probably was occupied by a distributary of this stream. During extreme
Flooding today, the excess water from Long Pond drains through this
valley.
The basin of Long Pond may have developed initially along the foot
of the fault escarpment in irregularities of the ground surface, solution
of the limestone bedrock possibly being accelerated by fracturing along
the fault zone. The downthrown side of the fault would develop a wide
and irregular basin, which apparently has been narrowed by alluviation
and deposition of brackish-water sediments during the Pamlico stage.
SPRINGS
Springs are of two types. In one the water is derived from local rainfall
under ground-water table conditions, in which the water enters at a high





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


elevation and emerges along lower elevations in stream valleys and
lake basins. In the other the water rises from depth under artesian head,
the water having moved from some distance through the aquifer to
emerge in these counties. The first type are generally small springs or
seeps, but artesian water may issue as small springs, seeps and also as
copious flows of water. Several large artesian springs are present in
these counties and the water is beautifully clear and colored blue to
green, the color depending on the depth of water and the degree to
which light transmitted by the water is scattered by the water
molecules.
Wekiva Springs, Fanning Springs and Manatee Springs, in Levy
County, Homosassa Springs, Chassahowitzka Springs and springs in the
head of Crystal River in Citrus County are the larger and more beautiful
springs in the counties. Numerous seeps and springs in the coastal
hammocks are sources of water for sportsmen, and hunter's camps are
developed commonly at these sources. The channels of streams are a
maze of springs and seeps issuing from out of the limestone bedrock.
The springs are utilized in stock raising and as recreational areas, Manatee
being a proposed State Park. Many are commercialized. Excellent de-
scriptions of the large springs in the State were published in Florida
Geological Survey Bulletin 31 in 1947.

FRACTURING
Faulting has not been previously recognized in Florida and is mapped
in figure 11, and on Plate 1, for the first time. The fracture patterns,
shown as figure 11, were mapped from their physiographic expressions
as shown on mosaics and contact prints of aerial photographs, available
for each county except Orange, Taylor and a portion of Marion. They
have been checked geologically in the core hole section along the pro-
posed ship canal that crosses the western Peninsula at the Citrus-Levy
County line, by surface geology, and by preparation of detailed geologic
sections, figures 13 and 14 and a structure map, Plate 2.
In Citrus and Levy counties regional fractures parallel the axis of the
Ocala uplift and locate the crest of the fold exactly. These fractures
trend generally northwest-southeast. A secondary system trending north-
east-southwest intersects this system at large angles and are irregularly
spaced along the flanks of the uplift. Geologic sections crossing the Ocala
uplift show that many of the fractures paralleling the axis of the fold are
faults, but insufficient data are available on geologic sections crossing
transverse joints to determine the displacement along these.





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Figure 11 illustrates a fundamental regional pattern made by the
regular development of two systems of fractures trending northwest-
southeast and northeast-southwest. These are grouped irregularly at wide
intervals of 20 to 30 miles to form a rough rectangular pattern where
they intersect. Cross joints are only poorly developed along the crest of
the Ocala uplift, but are strongly developed and numerous along the
northwest plunge of the uplift in Jefferson, Madison, Hamilton and
Suwannee counties and sharply delineate the northwestern limit of the
crest of the fold. The southeast plunge of the fold is not as sharply
marked. The zero contour of the Inglis structure, Plate 2, has been drawn
on the map of the fracture pattern to illustrate the relationship of these
fractures to the Ocala uplift.

The systems of fractures can be traced from county to county
throughout the State and the northwest-southeast fractures appear to be
the major system. However, two well-developed patterns of fractures are
present that deviate from either of the systems described above. A
particularly well-developed set of fractures, radiating in all directions
from Union County, resemble in their pattern the fracturing that is
present over salt domes of the Gulf Coast. Another system located in
the southeast corner of figure 11 has fractures that trend more westerly
and are somewhat more irregular in pattern. The geologic-control data
in these areas are widely scattered and sufficient only to generalize on
possible causes of these fractures. Applin (1951a) has recently published
a critical analysis of the subsurface geology of the State. When the data
he has developed are superimposed upon the fracture pattern (see figure
11) they indicate some possible causes. The dome-like patterns in Union
County are located almost exactly over the area where Applin's pene-
planed pre-Mesozoic surface has been folded into an anticline, named
the Peninsular arch.
The distribution of possible pre-Cambrian crystalline rocks as map-
ped by Applin (1951a), corresponds remarkably well with the more
westerly trending fractures shown in the southeastern corner of figure
11. It is probably more than coincidental also that Applin's boundary,
believed to be a fault, separating Paleozoic sediments to the northwest
from rhyolite, tuff and agglomerate to the southeast corresponds closely
to the most strongly developed and distinctive northeast-southwest frac-
tures mapped on figure 11.
If the fracture pattern can be assumed to reflect these ancient land
.masses, they must do so through several thousand feet of Cretaceous,
Tertiary and younger sediments. The thickness may in fact provide the





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


mechanism for such expression, in the adjustment of relatively uncon-
solidated sediments over structurally stable and fundamental land masses.
'he writer does not attempt to explain the association of these fractures
with deeply buried structures, but the remarkably close relationship sug-
gests such a possibility.
The regional fracturing associated with the Ocala uplift is believed
to reflect structural movement during the late Tertiary. Stream patterns
and sink alignment commonly parallel both the northwest and the north-
east systems of fractures. Particularly well-developed expression of these
joints or faults are shown by the control of portions of the valleys of
the Ocklawaha, Withlacoochee and Kissimmee rivers, all of which show
strongly developed, rectangular trends northeast-southwest and north-
west-southeast with large angle turns. Some of the bay entries occur
where fractures intersect the coast, the high sand areas of Polk and
Hillsborough counties are bounded by strongly developed patterns, and
most of the larger springs of Florida lie in or along these fractures. The
fundamental pattern of joints and faults appears to be differential crustal
shifts along straight line fractures. Judging from their distribution and
alignment with the Ocala uplift the fractures are associated with land
movements of a regional nature and the stresses forming the folds of
the Ocala uplift created these joints and faults.
Considering the physical properties, low rigidity, high porosity, brit-
tleness and inherent weaknesses of the poorly consolidated Tertiary
limestones in which this fracture has occurred it seems impossible that
the Ocala uplift could have been formed in any other way than by com-
pressive stresses acting from the west against the Peninsular arch. When
thus analyzed there exists an arch about 230 miles long by 70 miles
broad which was gently folded and arched by compressive orogenic
forces. During the time these forces were elevating this heavy mass of
rock into an elongate anticline they were opposed by the weight of the
rock and there were two vertical compressive shearing stresses that cre-
ated horizontal tensional stresses at right angles to the compressive
forces and to each other. The fractures mapped in figure 11, are believed
to have formed under a combination of tensional stresses over the anti-
clinal flexure. The presence of tensional forces and stresses over folds
is almost universally accepted although they are not recognized to be
a local phenomenon. The compressive stresses effective all along the
arch would tend to concentrate shearing parallel to the axis of the fold,
although bulging along the flanks would have a similar effect. Most of
the traces on the crest, parallel to the axis, appear to be shear faults of
normal type. Primary tensile stresses would be developed parallel to the






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


compressive forces. Because of inequalities in these forces secondary
tensile stresses are developed at right angles to the primary tensile
stresses. Thus tensile fractures would be most strongly developed along
the axis of any folding and along the axes of flank bulges. This combina-
tion of stresses is capable of producing the regional fractures mapped in
figure 11. The poorly consolidated sediments composing Tertiary rocks
of Florida favor adjustments to strain by step fracturing rather than by
bending.
Because the tensional and shearing stresses would be greatest over
the up arched area of the Ocala uplift fracturing developed by them
would tend to occur in groups along the axis of the fold and to indicate
the direction of greatest stress and of the elongation of the arch. If these
joints are tensional they would tend to die out with depth because
stretching is greatest toward the outside and least toward the inside.
Available geologic data indicate that only tensional fractures are present
in the area and that these are shallow.
At least seven well-developed faults have been recognized in the
geological section drawn along the proposed Florida Ship Canal crossing
the State along the Levy-Citrus County line into Marion County, see
Plate 1, and figure 14. Each of these faults can be readily traced on
aerial photographs, on which they appear as continuous trough-like
depressions and ridges marked by significant vegetation changes and
soil colorations. These straight and continuous lines correspond exactly
with the map positions of vertical displacements of twenty to one hun-
dred and sixty feet along the section of figure 14. These vertical throws
are distributed along many closely spaced parallel faults, the planes of
which probably are inclined into the crest of the Ocala uplift. It was
impossible to make measurements on the limited exposures of the fault
traces, but the straight course of the faults across a very uneven topo-
graphy suggest that the planes of the faults are inclined very steeply.
The broad flat crest of the Ocala uplift, the straight-line traces and
presumable high dips of the fault planes, the inclinations of the fault
planes into the crest of the fold, the grouping of several essentially
parallel faults along the crest of the fold indicate that these faults are
normal dip-slip shear faults that have formed graben depressions and
horst ridges and flattened the crest of the Ocala uplift. The displacement
in the faults is apparently essentially vertical since the traverse fractures
are not interrupted where they cross known faults. The only indication
of horizontal movement is an abrupt change in the trend of the strongly
developed fractures running southwest from the Ocklawaha River Valley
to the point where the southern line of Hernando County intersects the






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


coast. At the point where these fractures cross a fault near the southern
boundary of Citrus County the trend changes abruptly to a more south-
erly direction and splits into three parallel joints. This change in trend
makes an angle too small to show in figure 11 on the scale at which the
map is reproduced but is evident on aerial photographs.
Following the development of the graben and horst structure, waste
would be expected to accumulate on the low-standing blocks, and the
fault traces would be concealed by sand and a residuum cover that masks
the structure. A definite fault zone, however, is exposed on the north-
east side of the Crystal River Rock Company quarry where the red
sands and clays of the Alachua formation have been deposited up against
and over large slump blocks, a fault breccia developed along one of
these faults. Well-developed fractures are also rarely exposed at the sur-
face because younger sediments cover them and mask the identifying
features, but some evidence can be seen in joints exposed along the
highway to Cedar Keys; along the old highway near Inglis in the center
of the northeast quarter of Section 35, Township 16 South, Range 16
East, figure 12; and at Red Level where dolomitization has apparently
extended along one of these fractures. It is not surprising that in a thick
limestone section containing little close zonation and covered by con-


Figure 12. Differential weathering along a fracture in the limestone of the Inglis
member, Moodys Branch formation, trending northwest-southeast as
exposed in Section 35, Township 16 South, Range 16 East.





52 FLORIDA GEOLOGICAL SURVEY- BULLETIN 33

siderable Pleistocene and Recent alluvium and marine deposits that these
small faults have gone so long without being recognized. Under these
conditions only a large fault would be obvious and it has been necessary
to piece together small bits of evidence and to make careful observations
and correlations to obtain a reasonably accurate structural pattern and
history. There will undoubtedly be added by future explorations much
data that may completely change the interpretation of the structure as
described herein. Perhaps this description will serve as a basis for dis-
cussion from which the complete structural history of the area may be,
developed.
In mapping the joint pattern an attempt was made to include all ir-
regular trends whether poorly marked or well-developed, and to include
only the well-developed trends running northwest-southeast or at right
angles to this set.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


STRUCTURE AND SECTIONS

INTRODUCTION
A well-developed regional anticline developed in surface rocks was
described in a U. S. Geological Survey press release of 1920. The fold
was exposed in eastern Levy County and was named the Ocala uplift.
With the increased activity in prospecting for oil beginning about 1943,
it was discovered that the structure of older and deeply buried sedi-
ments did not conform to the structure developed in Tertiary beds. The
highest structure on Cretaceous and older beds was found to be centered
under Union County, with the crest of the structure trending northwest
and southeast from this area, paralleling the crest of the Ocala uplift.
Largely because the crests of the two structures were parallel and per-
haps for want of a better name, the Ocala tiplift was thought to be as-
symmetrical toward the east with depth and the term "Ocala uplift" was
extended to include the structure of older beds.
The study of the geology of Citrus and Levy counties shows that the
Ocala uplift crests in these counties and Applin (1951a, pp. 3-5) illus-
trated that the axis of the surface structure does not coincide with that of
the subsurface structure and that no close structural relations exist be-
tween the two features. He has contoured the subsurface structure and
named it the Peninsular arch. According to Applin (1951a, p. 3) the arch
". is the dominant subsurface structural feature of eastern Florida and an
adjacent part of southeastern Georgia. The anticlinal fold, or arch, which is
approximately 275 miles long, trends south-southeastward and forms the
axis of the Florida peninsula as far south as the latitude of Lake Okeechobee."
Applin showed conclusively that the deeper structure was formed
during the Mesozoic and was covered by transgressing beds ranging in
age from Lower Cretaceous through the Upper Cretaceous. Data are
presented in the present study which definitely indicate that the area
over the Peninsular arch was high through the Oligocene epoch and
that the Ocala uplift was probably initiated during the lower Miocene
epoch.
The term Ocala uplift is therefore restricted to its original usage to
apply to the dominant structures formed in Tertiary beds, with the
highest point of its crest located in eastern Citrus and Levy counties.
Well data indicate that the two structures, the Ocala uplift and the
Peninsular arch are not superimposed. Wells drilled on the crest of the
Ocala uplift penetrate the Peninsular arch well down on its flanks,
so that Tertiary beds which are structurally high overlie Mesozoic beds
which are structurally low, and conversely wells drilled along the crest






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


of the Peninsular arch begin in Tertiary beds that are structurally low
and end in older beds that are structurally high.
The structure map, Plate 2, has been drawn on the top of the Inglis
member of the Moodys Branch formation. Controls are based on out-
crops in Citrus and Levy counties and on well penetrations throughout
the north and central portions of peninsular Florida. The map indicates
that the Ocala uplift is not a simple, elongate, double-plunging anticline
but that it is composed of four separate structures that have deformed
Tertiary rocks. These structures include the crest of the Ocala uplift along
the western Peninsula and structures named the Kissimmee faulted flex-
ure, the Sanford high and the Osceola low in this report, Plate 2.

OCALA UPLIFT
The term "Ocala uplift" appears to have been published initially in
a press release dated April 19, 1920, issued by the U. S. Geological Sur-
vey. The release was a summary of oil possibilities in Florida based on a
study of surface geology and cuttings from wells made by O. B. Hopkins,
and was summarized by Gunter in 1921. The term has been used to apply
to dominant structural features of Florida since that time.
Hopkins' release clearly delineates that structure to which he applied
the name "Ocala uplift". He stated:
". .. the anticlinal fold trends south-southeast, and forms the axis of
the Floridian Peninsula. The axis of this uplift passes near Live Oak, 10 to 20
miles west of Gainesville, and an equal distance west of Ocala, and repre-
sents the southern continuation of the broadly anticlinal area of south-central
Georgia. There are two high areas along this anticline. One, called the Ocala
uplift, appears to have its highest part or crest in eastern Levy County, and
the other near Live Oak. Of these, the Ocala uplift is the larger and struc-
turally higher."
Hopkins' identification of the Ocala uplift was based on surface out-
zrops of Eocene limestone in western peninsular Florida and this work
has been well substantiated by later studies. However, his identification
of the "Live Oak uplift" was based on an inaccurate correlation of the
Oligocene-Suwannee limestone exposed along the Suwannee River with
the Miocene-Hawthorn formation cropping out at Live Oak, on an as-
sumed and inaccurate estimate of the thickness of beds covering the
Ocala limestone at Live Oak, on the apparently directed course of the
Suwannee River where it circles Live Oak before continuing its southerly
course, and on scattered well data which indicated that the Ocala lime-
stone was high at Live Oak.
In later years detailed work on additional data proved the Ocala
limestone had been extensively eroded prior to having been covered





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


by lower Miocene sediments and the "Live Oak uplift" was not sub-
stantiated by this work. Up until this report on Citrus and Levy counties
was nearing completion Tertiary structure maps were drawn on the
top of the Ocala limestone. The structures thus represented were merely
reflections of highs and lows in Tertiary beds and were not truly repre-
sentative.
Toward the completion of the work in Citrus and Levy counties it
was possible to subdivide the Ocala limestone, and a very characteristic
bed at the base provided an uneroded top, the contouring of which pro-
vided a more accurate map of Tertiary structures. The map is presented
as Plate 2, and it indicates that in fact Hopkins was partially correct in
depicting the Live Oak area as structurally high. The fault-flattened crest
of the Ocala uplift present in Levy, Citrus, Sumter, Lake and Polk
counties divides into two gentle folds, at the north Levy County line,
the crest of one trending almost due north from this point and passing
east of Live Oak, and the other continuing the northwest trend of the
crest of the Ocala uplift. The courses of the Suwannee and the Santa Fe
rivers have apparently adjusted to the slopes of the bedrock developed
along the flanks of these two folds.
The data on the geologic-history of the Ocala uplift and the structure
of surface beds can be illustrated best in cross section. The series of six
sections presented as figures 13 and 14 cross the State essentially per-
pendicular to the axis of the Ocala uplift and of the Peninsula. Sections
A-A', B-B', C-C', and E-E' are drawn along U. S. Army Engineers routes
7-A, 8-A, 12 and 13-B, alternate routes for the proposed Florida Ship
Canal. The ground surface for these sections is taken from published
reports of the U. S. Army Engineers, but the surfaces in sections AA-AA'
and D-D', and the eastern end of C-C' are approximate. Excellent core-
hole records and rock samples are available along each of the proposed
ship canal routes. These are generally quite shallow and deeper water
wells have been projected into these sections along the strike of the
Inglis member of the Moodys Branch formation, used as a structural
control bed. Sections D-D' and AA-AA' have been constructed from the
records of scattered water wells. Section AA-AA' extends easterly from
Tallahassee to Monticello, Florida, and connects into section A-A' at
well W-1596. The location of each section is shown on the index maps
of figure 13 and figure 14.
These sections and the structure map, Plate 2, indicate that the
Ocala uplift developed in Tertiary sediments as a gentle flexure, approxi-
mately 230 miles long, and about 70 miles wide where exposed in central
peninsular Florida. The anticline is composed of two well-defined shal-





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


low folds, the more westerly being higher structurally, see figure 13 and
Plate 2. Along the Florida-Georgia State line the east fold is separated
from the west fold by a shallow trough, 54 miles wide. The folds con-
verge southward and in Levy and Citrus counties they are separated by
only a few miles and their crests are extensively fractured and faulted.
The crests trend northwest-southeast through Levy and Citrus counties,
but in Sumter, Orange and Polk counties they diverge, the east fold
merging with a large fault block, named in this report the Kissimmee
faulted flexure, and the west fold continuing in a south-southeasterly
direction and gradually merging with the regional dip.
The development of vertical dip-slip faults, the traces of which
parallel the crest of the Ocala uplift, tend to flatten the crest and to
lengthen its cross-section. From the limited core hole evidence available
for this study the dip of the fault planes could not be determined, nor
was it possible to estimate the extent of faulting at depth. There are
numerous possibilities, one fault may terminate at depth against another
or it may cross to form a graben and horst structure. Figure 14 is one
interpretation of the geologic section along the proposed Florida Ship
Canal and here a graben and horst structure is clearly indicated. The
fault planes are drawn in at angles greater than 60 degrees and may be
steeper. They are thought not to dip at angles less than 60 degrees
because of the straight-line traces of the faults and because the closely
spaced core holes do not penetrate any thinning or thickening of the
beds.
THE KISSIMMEE FAULTED FLEXURE
Throughout an irregular area in the vicinity of Kissimee in Orange,
Osceola and Lake counties, wells penetrate a variable thickness of Mio-
cene sediments lying upon the Avon Park limestone. The Moodys Branch
formation, the Ocala limestone (restricted), and the Suwannee lime-
stone are not present, although they occupy their normal stratigraphic
positions in the surrounding areas. This high is the southern extremity
of a wedge-shaped block that is approximately 90 miles long along its
longest axis, 54 miles across the northwest border which is open, and 17
miles across the southeast margin, which ends at a fault forming the
northwest boundary of the Osceola low. The block is tilted with the
southeast end being upthrown, and it apparently has been rotated also,
the southwest boundary being higher than the northeast and the out-
crop pattern of the Avon Park limestone being extended along the south-
east boundary. The beds within the fault block are greatly disturbed,
many small folds and structural irregularities being present. Numerous
irregular fractures, figure 11, are present throughout the block and at





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


least one well-developed fault, Plate 2 and section D-D' of figure 13,
has been identified. Fractures appear to be concentrated toward the
southeastern extremity.
The southern portion of the block appears to be a small anticlinal
fold that trends west-northwest-east-southeast and terminates in both
directions against a fault. The Inglis member has been thinned over
much of the top of the block and removed from over the fold.
THE SANFORD HIGH
A semicircular area bordering the northeast boundary of the Kissim-
mee faulted flexure in the vicinity of Sanford, Seminole County, is
similar to the southeastern extremity of the Kissimmee faulted block in
many respects. Wells here penetrate the Avon Park limestone beneath a
thin veneer of Miocene sediments. The structure appears to be a closed
fold that has been faulted, the Sanford high being located on the up-
thrown side of the fault. The Inglis member of the Moodys Branch
formation has been thinned by erosion along the flanks of the fold and
removed from off the crest.
The similarity of the structures forming the Kissimmee faulted flexure
and the Sanford high, the presence of a fault separating them, and the
reconstruction of the stratigraphic section imply that the structures were
once continuous and have been offset by faulting and subsequently
eroded and covered by Miocene sediments. The reconstruction of the
pre-Ocala land surface and of this anticline indicate that it trended west-
northwest across the Peninsula and possibly connected the outcrop area
in Citrus and Levy counties. The presence of a structural high in and
near these counties during the early Eocene is indicated by the ex-
tensively cross-bedded limestones of the Inglis member that were formed
as shallow-water marine deposits that covered a land mass composed of
the Avon Park limestone. This land mass is also indicated by elements
of the Avon Park limestone reworked into the base of the Inglis member
and by an unconformity present at the base of the Moodys Branch
formation.
The faults bounding the Kissimmee faulted flexure cut all beds of
Eocene age and the irregularities created by erosion have been filled by
Miocene sediments. The age of these faults can thus be dated as post-
Eocene and pre-Miocene.
THE OSCEOLA LOW
The Osceola low is a wedged-shaped downthrown k bounded
on the northwest and east by normal faults, and open on dh. southwest.
Three wells, Florida Geological Survey wells W-1728, W-1749 and





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


W-1770, located in the northeast extremity of the low, penerate the
Inglis member at depths ranging from minus 412 to minus 482 feet. The
Inglis member lies below a normal thickness of the Williston member,
50 feet of Ocala limestone and a very thick section of Miocene sedi-
ments, up to 350 feet thick. This depth to the Inglis member contrasts
with the penetration of the bed at depths less than 200 feet to the east
and the absence of the bed along the fault block to the northwest.
The base of the Miocene contains no identifiable reworked fragments
of Eocene sediments. The absence of these implies that the faulting was
probably associated with movements that formed the Ocala uplift but
the faulting is younger than that which created the Kissimmee faulted
flexure and Sanford hiah.
STRUCTURES WITHIN CITRUS AND LEVY COUNTIES
Citrus and Levy counties are situated upon the crest of the Ocala
uplift and the regional dips of the Tertiary beds are southwest and
northeast along the flanks and northwest and southeast along the plunge
of this broad elongated arch, see Plate 2, figures 13, 14, and 15. The
dips are slight, the regional average approaching nine feet per mile on
the flanks and three feet per mile along the plunge, but dips greater than
these are present locally along small folds and in faulted blocks.
The Ocala uplift has been breached by erosion in these counties and
the Avon Park limestone of middle Eocene age is exposed in an irregular
dendritic pattern in southern and central Levy County and in north-
eastern Citrus County, see Plate 1. Younger beds of Eocene age crop out
in a concentric pattern about the Avon Park limestone. These ribbons of
outcrop are interrupted by horst-graben normal faults and outcrops have
been extended along the faults irregularly. In western Levy County and
west-central Citrus County two small sharply raised domes are indicated
by annular outcrop bands. These two domes and three major faults
crossing the counties are named and shown in figure 15. Smaller graben
and horst faults are well-developed but have not caused significant
changes in the regional outcrop pattern and although mapped on Plate
1 and Plate 2 they are not shown on figure 15 and are not named.
DOMES
There are included under this term two areas in which the outcrop
patterns are annular. These small domes have comparatively narrow
diameters and very slight dips. They may in fact be only minor flexures
in the folds forming the Ocala uplift. There is a possibility that they may
be the expression of deeply buried domes. Almost nothing is known
about their subsurface characteristics and until they are prospected in





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


detail the features are tentatively called domes because of their outcrop
patterns.
Homosassa Springs Dome: This dome is located just north of Homosassa
Springs in Citrus County. It exposes the Inglis member of the Moodys
Branch formation and is circled by a band of the Williston member of
that formation. The dome is about five by three miles, and adjoins a
small basin in which the Ocala limestone (restricted) is exposed and the
Crystal River springs are located. The northeast margin is bound by a
small graben, the southeast fault of which is exposed in the Crystal River


oBRONSON


5 0 5 10 Miles

Figure 15. The Principal structures in Citrus and Levy Counties.





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


-Rock Company quarry, located in Section 6, Township 19 South, Range
18 East.
The West Levy Dome: A small dome in western Levy County is exposed
as an island in the broadly developed hammocks along coastal and
Suwannee River lowlands. The area occupied by the dome is an outcrop
of the Inglis member and it is surrounded by a broad outcrop of the thin
Williston member of the Moodys Branch formation. The broadness of
the Williston outcrop implies very gentle dips westward, and the dome is
of little significance. Little is known of its subsurface characteristics but
the attitude of the beds could be determined by shallow prospecting.

FAULTS
The general development and description of fractures and faults is
given on pages 47 to 52. In Citrus and Levy counties sufficient details
have been accumulated to identify three major fault zones that are
named the Bronson graben, the Inverness fault and the Long Pond
fault.
Bronson graben: The graben upon which Bronson is located, is based
on studies of outcrops in which the Ocala limestone (restricted) was
identified within the graben, although older Eocene beds border it over
much of its extent and apparently end abruptly along its borders, indi-
cating faulting. In addition, well W-1870, at Bronson, bottomed in Ocala
limestone (restricted) at minus 87 feet without penetrating the Moodys
Branch formation, although well W-1633 about six miles southeast
penetrated this formation at 40 feet above sea level. The Moodys Branch
formation is exposed throughout a broad area west of Williston and over
a much broader area west of Bronson at elevations exceeding fifty feet
above sea level. The structure map, Plate 2, can be resolved only if a
graben or deep fold is placed across Levy County. The graben appears
to be the most logical of the possibilities and its bounding faults are
drawn along fracture traces as recorded on figure 11.
Inverness fault: The fault near Inverness is based on outcrops along the
Tsala Apopka Lake. The exposures of bedrock here and those uncovered
by phosphate mining in the area east of the fault are all limestone of the
Inglis member, Moodys Branch formation. These exposures lie at eleva-
tions of 28 to 50 feet above mean sea level whereas five wells, W-874,
W-1767, W-1791, W-1847 and W-1848, all located on the southwest side
and within two miles of the fault, indicate that the Inglis member lies
at elevations ranging from minus one in the south to plus 37 feet in the
north. Numerous exposures of the Williston member of the Moodys
Branch formation, the Ocala limestone (restricted) and the Suwannee





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


limestone on the hills southwest of the fault indicate comparable
displacements.
The northeast block has been tilted in faulting, the southeastern
portion being upthrown with a displacement of as much as 50 feet,
whereas the northwest portion is. downthrown with displacements as
much as 20 feet. The fault could be traced northeast into the Avon Park
limestone outcrop where it is either obscured or the structure absorbed
by possible incompetent beds.
Long Pond fault: This fault is the major fault in the area, and as much
as 160 feet of displacement has been recorded, see section E-E', figure
14. The fault is well exposed at Long Pond. Southwest of the lake on the
upthrown block, the Inglis member of the Moodys Branch formation
crops out on hills as hiqh as 35 feet above sea level. The outcrop patterns
of both members of the Moodys Branch formation are extended north-
west along this fault on the upthrown block. One and one-half miles east
of Long Pond on the downthrown block a dug well, located in the north-
west quarter of the northeast quarter of Section 8, Township 12 South,
Range 15 East, penetrated the Williston member at a depth of approxi-
mately sea level, indicating a minimum displacement of 50 feet. Near
the Levy-Citrus County line the Long Pond fault trace is paralleled by a
series of small faults. It is believed that the fault planes of these con-
verge and have formed minor horst-graben structures. In Citrus County
the Long Pond fault is either obscured within the outcrop of the Inglis
member, the displacements along the fault being too small to breach
the formation, or the fault ends abruptly in the area.

DATES OF STRUCTURAL MOVEMENTS DEFORMING
TERTIARY BEDS
Several portions of the geologic history and stratigraphy help in
dating the structural movements that have formed the Ocala uplift and
related structures. Some evidence is contained in the unconformity at
the base of the Moodys Branch formation and in the overlap of this
formation upon the Avon Park limestone in the outcrop area. The fault
zones that bound the Kissimmee faulted flexure cut beds as young as
the Ocala limestone (restricted) and are covered by lower Miocene
sediments. The adjacent Osceola low contains a very thick fill of
Miocene sediments, figure 33, which contain no identifiable residuum
derived from the erosion of the limestones exposed over the Kissimmee
faulted flexure.
Along the east side of the Florida Peninsula the upper Eocene and
Oligocene sediments are thin to absent when compared to the thickness





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


of these sediments over the crest and on the southwestern flank of the
Ocala uplift, the structural high in Tertiary rocks today, see sections of
figures 13 and 14. In Brevard, Orange, Seminole, Volusia and Flagler
counties, as shown in sections C-C' and D-D', the Ocala limestone
(restricted) and even the Moodys Branch formation are absent and the
Miocene rests directly upon the eroded surface. This unconformity con-
tinues northward into Georgia along the coast, where the Oligocene is
absent and the Hawthorn formation of lower Miocene age rests on the
Ocala limestone.
The Eocene and Oligocene beds are thin along the eastern coast line
of Florida even though the area is structurally low. The thinning of these
beds corresponds roughly with the crest of Applin's (1951a) Peninsular
arch, and the thinning and removal of Tertiary beds, apparently from
erosion, across the crest of this arch suggests that the eastern part of the
Florida Peninsula was high throughout the post-Oligocene, and that the
movements forming the Ocala uplift are post-Oligocene and pre-Miocene
in age. The inclusion of some basal Miocene beds in faulting along the
Ocala uplift, see section E-E', the overlap of a very eroded limestone
surface and the wedging out of Miocene sediments against the Ocala
uplift, see sections of figures 13 and 14, dates these movements fairly
definitely as lower Miocene in age. However, some of these structural
movements may have continued irregularly throughout later epochs, see
pages 29 to 31.
The Hawthorn formation is a wedge-shaped deposit, excessively
thickened toward the northeast and south, overlapping and pinching out
onto the structures composing the Ocala uplift. From the evidence pre-
sented in the sections and structure map the structural axis in Tertiary
beds through at least post-Oligocene time coincided with the axis of the
Peninsular arch and was located along the eastern seaboard. A secondary
axis may have been present during the late Eocene, extending more
westerly across the central Peninsula from Seminole County to Citrus
County, see pages 56 to 57.
Following an extensive period of post-Oligocene erosion Florida was
flooded by lower Miocene seas. The sequence of beds in the Miocene
indicate that these seas transgressed upon the Ocala uplift by a series of
overlaps and Miocene deposits pinch out against a well-developed
erosional surface. This transgression was apparently accompanied by
downwarping of the eastern and southern portions of Florida and the
elevation of the Ocala uplift along the western Peninsula. Evidence
presented under the discussion of the Alachua formation, pages 195 to
200, indicates that a large area situated upon the Ocala uplift was land
throughout the Miocene period, and was never covered by Miocene
seas.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


STRATIGRAPHY

PREVIOUS WORK12
The knowledge of Florida stratigraphy and structure was pioneered
by J. A. Cushman, W. H. Dall, E. H. Sellards and Herman Gunter. In
particular, Dall and Cushman deserve recognition for their identifica-
tions of the faunas of the different formations upon which much later
stratigraphic work was based. Cushman (1919) recognized the major
subdivisions of the Oligocene and Eocene and provided much of the
early identifications of foraminifers. Dall (1890-1908, 1892, 1894, 1897,
1915) recognized much the same subdivisions and his identifications of
mollusks were most important in the later classification of beds ranging
from Eocene to the Recent.
Cooke (1915) determined the Ocala limestone to be Jackson in age.
Sellards (1919), based his stratigraphy on fossil identifications of Cush-
man and Dall, prepared a sketch map of the geology and structure of
Florida and recognized the major stratigraphic subdivisions and regional
Tertiary structures of the State in a generalized fashion. This work was
amplified by Sellards and Gunter in 1922.
Important studies of stratigraphy and structure were presented by
Stuart Mossom (1926) in which the first structure map of Florida was
issued, the contours being drawn on the top of the Ocala limestone;
Herman Gunter (1928) announced the discovery of "basement rocks"
in a Marion County oil test well; Cooke and Mossom (1929) described
the surface geology of the State; Gravell and Hanna (1938) described
and figured several important guide fossils and recognized several zones
in the Tertiary, useful for correlation throughout much of the Gulf Coast;
Robert Campbell (1939) announced the discovery of Lower Cretaceous
beds in a deep oil test drilled in Monroe County, based on the identifi-
cation of foraminifers by E. R. Applin; Robert Vernon (1942) prepared
a report covering surface outcrops in Holmes and Washington counties,
Florida; Cole (1938, 1941, 1942, and 1944) in studies of wells drilled in
the State described and figured numerous species of Foraminifera, and
contributed to the knowledge of the subsurface stratigraphy. His 1942
study was of the Florida Oil Discovery-Sholtz and the Suwannee
Petroleum-Sholtz wells in Levy County, during which he subdivided the
Eocene section into an upper, middle and lower Eocene. He proposed
his Cedar Keys formation for the lower Eocene in his study of 1944. The
Applins (1944, 1947) and Applin and Jordan (1945) contributed to the
12Previous studies have been summarized by the Applins (1944, pp. 1674-77).
These are briefly listed here, with additions of work completed since 1944.





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


knowledge of the subsurface stratigraphy of the State. They described
and figured numerous species of Foraminifera, prepared excellent lists
of guide fossils, subdivided early and middle Eocene and the Cretaceous
and illustrated their studies by numerous sections and maps; Paul
Applin (1951a) recognized and named a deeply buried structure in
rocks older than the Mesozoic and subdivided these rocks into three
general classifications; crystalline rocks of possible pre-Cambrian age,
Paleozoic sediments, and possible Paleozoic volcanics. His study is an
important contribution to the knowledge of the early geologic history of
Florida, fundamental to the later geologic history.
Early in 1943 the writer found an exposure of dolomite south of Gulf
Hammock, Levy County, Florida, in which he found numerous casts and
molds of specimens of Coskinolina and Dictyoconus. These he believed
at the time represented beds older than the Ocala limestone. Both the
writer and Sidney A. Stubbs, formerly with the Survey, prepared in 1943
well logs in which beds of middle Eocene, "The Coskinolina zone", were
recognized. David Ericson (1945), working with the geologists of the
U. S. Army Engineers, recognized beds which he believed to be
equivalent to the Avon Park limestone and named surface outcrops the
"Gulf Hammock formation". The study of the geology of Citrus and
Levy counties was begun in 1946.

FLORIDA GENERAL STRATIGRAPHY AND STRUCTURE
The rocks that compose Florida are a portion of the Floridian
Plateau, which has apparently always been part of continental masses,
since the odtest sediments penetrated by deep oil test wells are shallow-
water marine deposits formed on continental shelves and no sediments
formed in- deep oceanic basins are present. The sedimentary section of
peninsular Florida consists essentially of fragmental and pasty marine
limestones, sandstones and shales reaching a known cumulative thickness
in excess of 18,000 feet. Only three deep wells have penetrated crystalline
rocks in Florida, granite was cut by the Humble Oil and Refining Com-
pany, Carroll well No. 1 in Osceola County, by the Oil Development
Company, Arnold well No. 1 in Lake County and hornblende diorite by
the Sun Oil Company, Powell well No. 1 in Volusia County. Because of
their stracigraphic position and crystalline texture, Applin (1951a) be-
lieved that the diorite is questionably pre-Cambrian and the others either
pre-Cambrian or Paleozoic intrusives. From Mr. Applin's study it can
be inferred that the core of the Floridian Plateau is pre-Cambrian and
that upon this rather poorly defined area dominantly marine Paleozoic
sediments, ranging in age from late Cambrian or early Ordovician to





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


Devonian, were formed. Twenty-seven deep wells in the State have cut
sandstdnes of the lower and middle Ordovician series, the Stanalind Oil
and Gas Company, Perpetual Forests, Inc., well No. 1 in Taylor County
penetrating a thickness of 2,250 feet of these sandstones. Three wells cut
black shales and sandstones 6f Lower Devonian or Upper Silurian age,
the Humble Oil and Refining Company, J. P. Cone well No. 1 in
Columbia County penetrating a thickness of 906 feet of these sediments.
These Paleozoic rocks were subsequently exposed to erosion and were
folded, possibly faulted and preserved in structurally low regions
throughout an extensive erosional period.
Th s eroded pre-Mesozoic surface, as described by Applin (1951a),
is highest in an arch centered at Union County, Florida. This structure
trends south-southeastward and was named the Peninsular arch. Folding
was accompanied by downwarping in southern Florida, and a thick
deposit of marine and deltaic sediments, largely carbonates, ranging in
age from possible Triassic to Recent, formed upon this land mass. Applin
(1951a), recorded that an extensive submergence began at the south
end of the Peninsula during the early Cretaceous and possibly Jurassic.
This is indicated in the Gulf Oil Corporation, State of Florida Lease 373,
well No. 1 on Plantation Key, Monroe County, which penetrated more
than 15,000 feet of limestone, dolomite, and anhydrites of Tertiary, Upper
Cretaceous, Lower Cretaceous and possibly Jurassic ages, whereas the
Sun Oil Company, Ruth M. Bishop well No. 1 in Columbia County
penetrated only beds of Tertiary age and those equivalent to the Austin
of the Upper Cretaceous. The submergence apparently advanced north-
ward along the Peninsula because the series of wells north of Sunniland,
Collier County, in which the beds of Trinity age are penerated at 13,000
feet show that beds of Trinity, Fredericksburg and Washita age overlap
and encroach progressively upon the floor of eroded pre-Mesozoic rocks.
These definitely marine beds interfinger northward into a elastic facies
of red and green shale, sandstone and siltstone that occupies the south
flank of the Peninsular arch and are correlatives of Trinity to Washita
sediments (the Comanche series of the Lower Cretaceous), see figure
16, section, B-B'.
The Peninsula of Florida was covered by shallow marine waters
throughout the period extending from the Paleocene to the Recent, ex-
cept for brief periods when it stood as land and was weathered and
eroded. Except for the sediments of Miocene to Recent age these deposits
are composed essentially of carbonates, with thin beds of evaporites,
sandstone and shale.
In general the Tertiary sediments of the State are composed of two






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


depositional facies, an essentially marine and carbonate facies and a
more shallow-water elastic facies, a small proportion of which is also
marine. The coastal plains of western Florida and states westward to
Texas have been in general a region of active deltaic sedimentation. On
the other hand peninsular Florida, removed from large streams and
continental sedimentation is dominantly marine. The two extremes merge
through interfingering phases in the coastal areas of Alabama, western
Florida, and northern-central Florida. As the Applins (1944, pp. 1679-80)
stated:
"... On the one hand, west Florida and southern Georgia are occupied by
a elastic facies which is similar in its broader aspects to the sediments of the
Western Gulf Coastal Plain and is composed largely of sand and shale with
some limestone and chalky marl. On the other hand, over most of the penin-
sula, the sedimentary section is almost continuous limestone from the top
of the Oligocene into the Lower Cretaceous In northern Florida and in
the north quarter or north third of the peninsula, the limestone and elastic
facies grade laterally into each other. In general, with the passage of time,
the limestone of the peninsula encroaches upon the elastic facies, spreading
northward in successive stages In general also, the foraminiferal micro-
faunas of the elastic facies resemble those present in formations in the western
Gulf Coast, whereas the microfaunas of the limestone facies in the peninsula
from the top of the early middle Eocene to the top of beds of Taylor age
resemble those of Cuba, the West Indies, Mexico, and Europe, with only few
species present that are known in other places in the United States. Species
of ostracods and bryozoans show a like dissimilarity with those found in west-
ern faunas. Beginning with the top of the beds of Taylor age in the peninsula,
the more familiar Gulf Coast microfaunas again appear. Some mingling of
faunas of the two facies has been noted in a few wells in north Florida in the
early middle and lower Eocene, but none in the Paleocene or late Upper
Cretaceous. The fauna of the Lower Cretaceous limestones of southern Florida
again resembles that found in certain derived deposits in Cuba and also that
of the El Abra limestone of southern Mexico (Cenomanian-Albian) there
designated as Middle Cretaceous."

GENERAL STRATIGRAPHY OF CITRUS AND LEVY
COUNTIES, FLORIDA
Oil prosnects hive nowhere in Citrus and Levy counties passed
through beds older than Paleozoic. In Levy County, the Coastal Petro-
leum Company's James B. and Julian P. Ragland No. 1 well bottoms
in beds believed to be Upper Silurian or Lower Devonian, and the
Humble Oil and Refining Company's C. E. Robinson et ux No. 1 well
and the Sun Oil Company's J. T. Goethe well No. 1 ended in sandstone
of the Middle Ordovician.
The data from these wells indicate that Cretaceous beds lie directly
on beds of Paleozoic age, separated by an unconformity representing









SUB-SURFACE BEDS SURFACE BEDS


Paleozoic Mesozoic Cenozoic



'i 0
o n


S' S "' Cretaceous Tertiary Quaternary q. i5.




a 22

S Gulf Eocene n Pleistocene .

S!

0 ".1 Atkinson W n Moodys 0 "
S, formation 2 0 | q PBh CL 7 O|- P M Bnch 4 A I
on W. formation C a o
(D Jackson
(D W g > V, ae 0 C (t

C ) 2. ( D 0 |
oU o CD M B B 0

wn CD CD S ;ZOn


0 p 0 on B 0 s 0 -





FLORIDA GEOLOGICAL SURVEY BULLETIN 33


several geologic periods. see figure 16, section A-A'. This would indicate
that the western peninsula of Florida was land for a long period prior
to deposition of the Cretaceous beds. This and the geologic history as
interpreted from well penetrations imply that these counties have been
a part of a structurally stable land mass which was gradually covered
by overlap of Cretaceous and younger sediments. The area, essentially
a peninsula since the early Cretaceous, was a shoal, surrounded by
deeper water, or land that separated the Gulf from Atlantic waters.
The sequence of formations, penetrated by wells, and those exposed
at the ground surface of Citrus and Levy counties is given in Table 6.

PALEOZOIC ERA
The deeper oil prospects in Citrus and Levy counties bottomed in
beds believed to be Lower Ordovician and Upper Silurian or Lower
Devonian in age. However, several wells drilled as oil tests in the State
have penetrated additional Paleozoic sediments. Dr. Josiah Bridge and
Dr. Jean Berdan have been engaged during the past two years in a study
of these beds. They have completed their study and have been kind
enough to prepare for inclusion in this paper some notes on the
Paleozoic strata of Citrus and Levy counties.
Since no conclusions can bp drawn on the limited information available
from the samples taken from the three wells that penetrate Paleozoic
sediments in these counties, and time has not permitted a critical study
of wells outside these counties, the paper by Drs. Berdan and Bridge is
presented here.

PRELIMINARY NOTES ON THE PALEOZOIC STRATA BENEATH
LEVY AND CITRUS COUNTIES, FLORIDA
By Jean Berdan and Josiah Bridge
Three deep wells drilled in southern Levy County in search of oil en-
countered early Paleozoic strata lying unconformably beneath Mesozoic
rocks. Data on these wells are summarized in Table 7. No other deep
wells in either county have reached Paleozoic rocks, but they have been
encountered in a number of wells in the counties lying immediately to
the north and east of Levy County and in a single well in Hernando
County, directly south of Citrus County. From this it is reasonable to
assume that both counties are underlain by Paleozoic rocks, and evi-
dence from other areas indicates that they are quite thick. Still farther
to the south and southeast several wells pass directly from Mesozoic sedi-
ments into crystalline rocks of various types that are believed to be of
Pre-Cambrian or early Paleozoic age.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


The top of the Paleozoic rocks in southern Levy County lies at depths
between 3960 feet (Goethe) and 5792 or 5810 feet (Ragland) below
sea level, and this taken in conjunction with the elevations of the top
of the Paleozoic in wells in adjacent counties indicates the presence of
a well-developed peneplane surface on the Paleozoic rocks. This surface
slopes gently southwest from an elevation of about 3500 feet below sea
level in the northeastern part of Levy County to around 7000 feet below
sea level in the southwestern part of Citrus County; the average slope
of the surface being about 100 feet per mile, or slightly more than one
degree (see Applin, 1951, p. 4).
The Ragland well cut about 40 feet of soft, laminated, somewhat silty,
finely micaceous and pyritic, very dark gray to black shale, of which
only the bottom 10 feet was cored. This bottom core contains a poorly
preserved fauna consisting of crinoid stems, hyolithoids, cephalopods,
pelecypods (probably Actinopteria) and a few other forms. A similar
association of fossils in a better state of preservation has been found in
the Humble Oil and Refining Company's J. P. Cone No. 1 well, in north-
ern Columbia County, which cut 962 feet of a lithologically similar black
shale without passing through it. From this it seems reasonably safe to
infer that the Ragland well may have penetrated only the upper part of
a considerably thicker shale section. A preliminary study of the better
preserved fossils in the Cone well indicates that the probable age of this
black shale fauna is Upper Silurian or Lower Devonian.
Overlying the black shale in the Ragland well is about 18 feet of
unctuous yellow, gray, lavender and pink variegated well-stratified shale,
the age of which is still under discussion. It is comparable in position
and lithology to a zone of unctuous variegated shale which occurs over
the black shales in the Cone well, and which contains fossils similar to
those found in the underlying black shales. In the Ragland well this
material is unfossiliferous, but has been considered by some to be
analogous to the shales in the Cone well, which are believed to represent
a weathered phase of the Paleozoic shales which is still in place and
therefore a part of the Paleozoic sequence. However, others believe that
the variegated shales are reworked and redeposited material derived
from the weathering and subsequent erosion of the Paleozoic beds, which
has been transported and rearranged and is therefore the basal part of
the Mesozoic sequence. As, in the Ragland well, these beds are overlain
by a conglomerate of quartzite pebbles which is apparently early
Mesozoic in age, and as deeply weathered strata are a normal occurrence
just beneath a peneplaned surface and their preservation and subse-
quent burial beneath the sediments of a younger cycle is not unusual,






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


the first hypothesis is preferred and the variegated shales are considered
to represent a weathered part of the underlying black shales.
The Robinson well penetrated one or more sills or flows of diabase,
46 feet thick, presumably of Triassic age and lying just beneath the
peneplane surface, and then cored 232 feet of Paleozoic sediments, chiefly
light gray, hard, quartzitic sandstone, locally interbedded with films
and thin beds of rather hard, dark gray to black, somewhat silty, mi-
caceous shale. A few fossils, chiefly linguloid brachiopods belonging to
two or more species, were found in the quartzites in the upper part
of this section (between 4390 feet and 4424 feet), and, on this basis, the
strata in this well have been correlated with those in the Union Pro-
ducing Company's E. P. Kirkland No. 1 well in Houston County, Ala-
bama, just north of the Florida line and 211 miles northwest of the
Robinson well. The same types of linguloid brachiopods and the same
lithology are found in both wells, and the Kirkland well also carries
abundant graptolites associated with the linguloids. The graptolites fix
the age of the strata containing them as Lower Ordovician, equivalent
to a part of the Deepkill shale of New York. This zone is not known in
the southern Appalachian Valley, but is represented by beds carrying
the same types of graptolites in Arkansas (shale beds in the Blakely
sandstone) and in West Texas (part of the Marathon formation).
Another feature common to the Paleozoic strata of both wells are
vertical worm borings of the Scolithus type. These average about 0.25
inch in diameter, and may be as much as 8 inches long. They occur in
zones or beds from 4 to 8 feet thick, separated by barren intervals of
about the same thickness. The tubes are filled with sand cemented to
quartzite, and within them all traces of bedding are destroyed. They
contain no visible shale particles, and where they cut through shale
layers and films, appear as white, circular spots on the bedding planes.
Where the tubes cut across the individual laminae, the latter are com-
monly disturbed and deflected. Although these tubes are admittedly
facies fossils, restricted to a sandy environment, they nevertheless ap-
pear to have definite value in local correlation.
The J. T. Goethe No. 1 well, about 10 miles north of the Robinson
well, cut 37 feet of gray quartzitic sandstone and micaceous black shale
similar to the material just described from the Robinson well. A part of
this interval was cored, and these cores contain vertical worm tubes
similar to those just described. Although no other fossils were found, a
circumstance which is not surprising in view of the limited amount of
material available for study, it seems quite reasonable to correlate this
material with some part of the section found i- the Robinson well. Most





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


of the deep wells in the adjoining counties also penetrated similar rock,
and one of these, the Sun Oil Company's Perpetual Forest No. 1 well
in Section 5, Township 11 South, Range 11 East, in Dixie County, cut
2250 feet of similar material without passing through it. It seems certain
that the sections encountered in the Robinson and Goethe wells repre-
sent some part or parts of the section cut in the Perpetual Forest well,
that the Paleozoic section underlying Citrus and Levy counties is of
considerable thickness, and that somewhere beneath it at unknown
depths crystalline rocks would probably be found.
No other types of Paleozoic sediments have been penetrated in the
wells drilled in Levy and adjoining counties, but Paleozoic strata be-
longing to some of the intervening Ordovician and Silurian horizons
have been found in wells drilled in northern Florida and southern Geor-
gia. This stratigraphic and structural relations of the Ordovician and
Silurian rocks underlying these counties are not known. From the fact
that the strata are essentially flat-lying, and because other horizons that
would normally lie between them are unknown here, it is believed that
they are possibly in fault contact (see figure 16), the age of the faulting
being pre-Cretaceous.

MESOZOIC ERA
TRIASSIC SYSTEM
Triassic Sediments and Intrusives
As indicated on page 69, a thin section of variegated shales occur-
ring at depths of 5,792 to above 5,810 feet in the Coastal-Ragland well is
believed by some workers to have been reworked and redeposited sedi-
ment derived from weathering and erosion of Paleozoic rocks. This bed
has been tentatively placed in the Lower Cretaceous system by some
workers, and it could be Triassic, but is considered a logical part of the
Paleozoic system in this paper.
The Humble-Robinson well penetrated a sill(?) of igneous rock at
least 46 feet thick at depths of 4,331 to 4,377 feet. The upper portion (4,331
to 4,344 feet) of the rock is considerably altered and the rock is quite
calcareous. Serpentine and alteration products are common, and portions
of the weathered material appear to have been reworked and included
in the overlying light-greenish, soft sandstone of Mesozoic age. The rock
is believed to have intruded Paleozoic sediments and its weathered sur-
face to represent a long period of erosion and peneplanation extending
through the early Mesozoic. It is a greenish-black diabase made up large-
ly of thin laths of plagioclase feldspars, augite and a rhombic pyroxene,
enstatite, with interstitial quartz and needles of apatite. The lower part







TABLE 7.-Paleozoic Rocks in Citrus and Levy Counties.


Company



Coastal Petroleum Co.






Sun Oil Co...........








Humble Oil and
Refining Co.........


Well



JB & JT
Ragland No. 1;
Sec. 16, T. 15 S.,
R. 13 E.


JT Goethe No. 1;
Sec. 31, T. 14 S.,
R. 17 E.






CE Robinson
No. 1;
Sec. 19, T. 16 S.,
R. 17 E.


Date
Completed


Oct. 18, 1947


June 8, 1946 45


Aug. 20, 1949 58


Depth to
top of
Paleozoic
and T.D.


5810' or
5792'

5850'


3960'

3997'






4377'

4609'


Elev.-Top
Paleozoic
below zea
level


-5795' or
-5777'





-3915'


Thickness
Paleozoic
penetrated


40' or
58'





37'


-4319' 232'


Lithology
of
Paleozoic


Black,
silty
shale.



Gray
qtzitic
ss. and
black, mi-
caceous
shale.


Gray
qtzitic
sandstone
and black,
micaceous,
silty shale


Type of
record


Cuttings,
core 5840-50





Cuttings and
core







Core


Age
0



Upper Silurian C
or Lower
Devonian
0



Lower
Ordovician?


I
to


Lower
Ordovician


-----





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


has many inclusions of a black, waxy, clay-like substance and much cal-
cite occurring as veins and as alterations of silicates along the veins.
Because of the known distribution of diabase in Triassic sediments of
the eastern United States along the Appalachian Mountains of the At-
lantic border, the similarity of diabase penetrated in Florida to that of
known Triassic rock, and its placement in Paleozoic and burial by Cre-
taceous sediments this rock has been referred to the Triassic system.
Their hardness and resistance to weathering suggests that these sills stood
as ridges forming some relief on the great plain developed on top of the
Paleozoic rocks.
The Humble-Robinson well in Central Levy County also penetrated
13 feet of green arkosic sandstone containing brown sideritic shale lenses
which was apparently derived from the weathering of the Triassic (?)
diabase. This sandstone lies below Lower Cretaceous sediments and
because of this association is believed to represent the basal part of these
beds developed as mantle rock during the early Cretaceous and covered
by Lower Cretaceous beds sometime later. There is the possibility, how-
ever, that this development of the weathering profile extended over
periods of time prior to the Lower Cretaceous.
If the sediments described from the Coastal-Ragland and Humble-
Robinson wells are Triassic in age there would be an unconformity at
the base of the Triassic system in Levy and Citrus counties. These sedi-
ments rest directly on Lower Devonian or Silurian rock and it is known
that in other parts of North America the Paleozoic era is represented by
a large interval of time which is missing in the section of Levy and
Citrus counties. There would likewise be a missing interval of time
separating this apparently deeply weathered Paleozoic shale from the
overlying Lower Cretaceous sediments and an erosional unconformity is
present.
The evidence of Triassic diabase is limited to discontinuous diamond
cores and the relationship of the flow or sill to the underlying rock can
only be surmised. Nothing can be detected as to the large structures of
the igneous body. A careful study of the sediment under the lava indi-
cates a two-inch black, silicified, dense shale which may be a contact
reaction zone.
The fresh rock of the cores is a deep bluish-black color, and the
weathered a light-greenish to yellowish gray. Both effervesce with cold
diluted hydrochloric acid, the weathered doing so much more freely.
In thin-sections13 both rocks show an even granular diabasic texture
s1Petrology determined by Dr. James L. Calver, Geologist, Florida Geological
Survey from thin-sections cut from the top and bottom of a six-foot core taken at
depths of 4,344 to 4,350 feet.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


and a subordinate aphitic structure. Extreme alteration of the ferromag-
nesian and feldspar minerals have taken place and the feldspars have
in many places been replaced by calcite. This replacement is greater in
the weathered specimens of the rock. What is presumed to represent
the weathered upper surface also contains pale-green, fibrous aggregates
of serpentinous and chloritic substances, and more calcite than the fresh
rock. Chlorite is more abundant than the serpentine which is probably
the variety bastite, a weathering product of the rhombic pyroxene. In
the weathered rock the pyroxene has been altered to ferrous oxides and
carbonates, largely siderite and limonite. Fractures in the rock are filled
by calcite, siderite, and rarely a serpentinous mineral. The fractures in
the weathered diabase are laminated with alternating layers of calcite
and siderite, but fractures in the unweathered diabase are rarely filled
by secondary minerals. No distinct pattern to the fracture is observable
from the limited cores made available to the Survey. In these cores the
contact at the base of the diabase is sharp but that at the top is grada-
tional because some of the products of weathering of the diabase are
included in the overlying sediments.
The diabase rests on a two-inch bed of black, dense, hard, silicified
shale, which lies on unweathered quartzitic sandstone of Paleozoic age.
Since it is known that much of the time record represented elsewhere
by upper Paleozoics is absent in these counties and that a long erosional
period is represented at the top of the Paleozoic section of Citrus and
Levy counties, the shale may represent a soil zone developed on the
Paleozoic sandstone and baked and silicified by a diabase flow, but more
probably it is a metamorphosed contact zone beneath a sill.
The lower part of the diabase is greatly fractured, although the dia-
base is unweathered, and calcite has filled the fractures. This bottom
also contains phenocrysts and inclusions of oily, greenish-black, unctuous
greatly altered shale from below. The fracturing at the base may indi-
cate cooling followed by a continued flow during emplacement.

CRETACEOUS SYSTEM

INTRODUCTION
The weathered mantle rock developed over the crest of the Peninsular
arch was almost completely removed and relatively unaltered Paleozoic
sediments and igneous rocks lying beneath Upper Cretaceous marine
sandstone, shale and chalk are penetrated by wells. This mantle rock,
deposited along the flanks of the land mass and merging with marine





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


sediments, has resulted in a generalized two-fold division, a red-bed
plastic facies and a marine and evaporite facies. The red-bed plastic facies
is confined largely to the Lower Cretaceous although some of these
plastics in western Florida have been called Triassic. The basal Upper
Cretaceous is commonly marine sand, sandstone and shale in peninsular
Florida but red-bed plastics are present in southern Georgia14 in beds
as young as the Austin equivalent.
The distribution and relationship of the Cretaceous beneath Levy
and Citrus counties can best be shown in cross section and by structure
maps, figure 16. Section A-A' is based on six wells in Levy County
and B-B' on five wells, the Coastal-Ragland well in Levy County being
common to both sections, and includes four additional wells toward the
south in Hernando, Hillsborough, Hardee and Highlands counties. Sec-
tion B-B' is modified from data published as chart A-A' of the South-
eastern Geological Society Mesozoic Committee, 1949.
In the continuous line of wells connecting the Highlands County
well with the Coastal-Ragland well, progressive marine overlap of Cre-
taceous beds is clearly shown and the possibility that some of the Lower
Cretaceous red-bed plastics are shallow-water equivalents of these ma-
rine beds is also indicated.
Section A-A' illustrates the abrupt thinning of the Lower Cretaceous
plastics toward the crest of the Peninsular arch, and both sections show
that the Cretaceous is dipping away from the crest of the arch, indi-
cating some movement in the structure following deposition of the
Upper Cretaceous beds. The dip and strike of Cretaceous sediments are
illustrated further by the structure map of figure 16. The top of the
Lower Cretaceous and a characteristic shale break in the basal beds of
the Taylor equivalent as penetrated by wells in Levy and adjacent
counties have been contoured. The dips of both beds are approximately
the same, being about 20 feet per mile south in Levy County and
counties to the north and steepening to about 40 feet per mile further
south. The approximate eastern limit of the Lower Cretaceous elastic
red beds is also shown.
The Atkinson formation, equivalent of the Eagle Ford shale and the
Woodbine sand, shown in sections A-A' and B-B' pinches out toward
the crest of the Peninsular arch and is overlapped by limestones and
chalks of the Austin equivalent.


4Southeastern Geological Mesozoic Committee, Mesozoe cross sections, 1949.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 83


LOWER CRETACEOUS(?)
Comanche Series
Only four wells have penetrated the Lower Cretaceous in Levy
County and none in Citrus and, as typified by cuttings and cores taken
from these wells, these sediments are variegated red, green, and brown
plastics, largely sands and shales, that apparently are weathered rocks
removed from a pre-Mesozoic near-peneplaned surface and redeposited
along the flanks of the surface as it was warped throughout the Cre-
taceous period, or they are the residuum from the weathering of the
rocks exposed at the surface of the land mass, remaining as mantle rocks,
largely undisturbed.
The thickness of the Lower Cretaceous ranges from 1,435 feet in the
Coastal-Ragland well in western Levy County, to 31 feet in the Humble-
Robinson and 67 feet in the Sun-Goethe wells in central Levy County.
The sections and distribution of the Cretaceous, see figure 16, indicate
that the thickness of the Lower Cretaceous beneath Citrus County has
increased slightly over the maximum of 1,435 feet as penetrated in Levy
County by the Ragland well.
The sediments of the Lower Cretaceous are interbedded shales and
sandstones. The shales are red, purple, green, brown and gray variegated,
mottled, waxy and fissile and contain pink calcareous nodules, yellow,
pink, argillaceous sand lenses and sand grains of rose quartz. The sand-
stone is variegated, light-greenish to yellowish-gray, brown, and white,
calcareous and siliceous, and contain black siliceous nodules, rose quartz
sand grains, seams of sandy shale and lenses of quartz conglomerate. The
base is coarse sand and contains pebbles of Paleozoic sediments. An
arkosic sandstone, believed to be a mantle developed by the weathering
of Triassic diabase was penetrated by the Humble-Robinson well at
depths of 4,331 to 4,344 feet.
Lower Cretaceous beds were penetrated by the following wells:
W-855: Florida Oil Discovery Company, Sholtz (Cedar Keys) No. 2.
SEl NWI Sec. 16, T. 15 S., R. 13 E.
Lower Cretaceous: 4,254 to 5,248 feet.
W-1007: Sun Oil Company, J. T. Goethe No. 1.
NW% SWK Sec. 31, T. 14 S., R. 17 E.
Lower Cretaceous: 3,893 to 3,960 feet.
W-1537: Coastal Petroleum Company, Ragland No. 1.
SE, SW4 Sec. 16, T. 15 S., R. 13 E.
Lower Cretaceous: 4,347 to 5,782 feet.
W-2012: Humble Oil and Refining Company, Robinson No. 1.
NE3 NEX Sec. 19, T. 16 S., R. 17 E.
Lower Cretaceous: 4,300 to 4,331 feet.






GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


UPPER CRETACEOUS

Gulf Series
Studies of the Cretaceous stratigraphy have been published by Applin
and Applin (1944, 1947), Cole (1938, 1941, 1942, 1944, 1945), and the
Southeastern Geological Society Mesozoic Committee (1949), in which
correlations of the Florida Cretaceous with standard sections of Alabama
and Texas have been made. The correlations apparently were based on
the experience of the workers and on the lithology and paleontology of
the several sections. Many early workers1 and Cole preferred to use the
nomenclature of the Alabama section, whereas the Applins and the
Southeastern Geological Society Mesozoic Committee have used the
names applied to the Upper Cretaceous of Texas, in which many of the
species of foraminifers and mollusks that occur in Florida are found.
Most geologists of the oil profession of the southeastern states prefer to
use a nomenclature of Beds of Navarro age (Lawson limestone), Beds
of Taylor age, Beds of Austin age (which include the Selma equivalent
at the top and occasional beds of the upper Eutaw sand at the base)
and the Atkinson formation. Some workers prefer not to use Atkinson
and divide the interval into the Eagle Ford shale and Woodbine sand.
In general all workers recognize a four-fold division of the Upper
Cretaceous, based on an age relationship. The Southeastern Geological
Society Mesozoic Committee used Navarro equivalent, Taylor equivalent,
Austin equivalent and the Atkinson formation, divided into "A" andd "B"
zones, and this terminology is used in this report with the exception that
the Lawson limestone is used for the Navarro equivalent.
The Upper Cretaceous of the peninsular area is composed of cream-
colored to brown, pasty and fragmental rarely oolitic, marine chalky lime-
stone, dolomitized in part and with abundant fossils. Incipient dolomiti-
zation and gypsum impregnation are present rarely. The base of the
section contains lenses and laminae of brown to black shale, green
bentonitic shale and thin beds of glauconitic fine sand containing some
gravel.
Beds of the Upper Cretaceous lie unconformably upon older beds,
and in Citrus and Levy counties individual beds of the series appear to
be conformable with each other. An unconformity is also indicated at
the top of the Upper Cretaceous in the Humble Oil and Refining Com-
pany, C. E. Robinson well No. 1, where the overlying Paleocene Cedar
Keys formation contains gray, chalky, limestone pebbles in the very base.
15Geologic logs in the files of the Florida Geological Survey.





FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Applin and Applin (1944, p. 1703) likewise indicate an unconformity
separating Paleocene from Upper Cretaceous in the vicinity of Talla-
hassee where the Cedar Keys formation rests on beds of Taylor age,
with the Navarro equivalent being absent.

ATKINSON FORMATION
During an investigation of the stratigraphy of Cretaceous rocks in
Alabama, Georgia and north Florida, the Applins (1947, chart) deter-
mined that:
"The subsurface deposits between the base of the beds of Austin age and
the top of the Lower Cretaceous should be considered as a unit in order to
explain changes in depositional facies which appear in the upper part of the
sequence.
Beds occupying this horizon in the subsurface could not be correlated
exactly by the Applin's with either the surface exposures of Alabama
or with the subsurface classification of Mississippi, because of lithologic
and faunal differences. The Atkinson formation, including three unnamed
members, was proposed for the early Upper Cretaceous and was ten-
tatively correlated with the Tuscaloosa formation and the McShane for-
mation of Alabama. The Applins expressed the desire that the name
would be sufficiently flexible to allow the extension of the surface
nomenclature at a later date if desirable.
The Atkinson formation has been adequately described by the
Applins and this description is not repeated here. The two basal members
contain microfossils and mollusk fragments typical of the Woodbine sand
of Texas, whereas the upper member contains a fauna characteristic of
the Eagle Ford shale of Texas. On the basis of these faunas the South-
eastern Geological Society Mesozoic Committee used a two-fold division
of the Atkinson formation, an "A" and "B" zone; the "A" zone containing
an Eagle Ford fauna, the "B" zone a Woodbine. This division is used in
this report.
The Atkinson formation was penetrated in four wells in Levy County.
Evidence presented by the Applins (1947, chart) indicates that the
Atkinson is possibly absent in eastern Levy County and it is known to
be absent over the crest of the Peninsular arch. However, the absence
of the formation in Levy County is not substantiated by the section,
figure 16, and perhaps the formation thins rapidly in Marion County and
is absent over most of it.
The formation is fairly uniform in thickness ranging from 240 feet in
the Sun-Goethe well, 244 feet in the Florida Oil Discovery-Sholtz well to





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


36S feet in the Humble-Robinson well, the thickening occurring in the
upper "A" zone.

"A Zone": This zone commonly contains in marine shale beds a fauna
characteristic of the Eagle Ford shale of Texas and includes Planulina
eaglefordensis, Valvulineria infrequens, Gumbelina moremani, G. reussi,
Trochammina wickendeni, Globigerina cretacea and numerous ostracods.
In western Levy County it is composed of medium-gray to greenish-gray,
calcareous, micaceous shale containing seams of argillaceous limestone
and variegated, micaceous, glauconitic, pyrite and carbon flecked sand-
stone. Eastward the zone thickens from 190 feet to about 250 feet and is
composed of interbedded, light-brownish to medium-gray, sandy, dense,
hard, shaly limestone with thin seams of sandstone and flecks of lignite;
greenish-gray, poorly sorted, slightly calcareous sandstone; and purple,
blocky, micaceous shale. Poorly preserved mollusk shells and fish scales
are fairly common in the shale beds.

"B Zone": This zone contains a microfauna characteristic of the Wood-
bine sand of Texas, including Ammobaculites braunsteini, A. compri-
matus, A. advenus, Ammobaculoides plummerae, and Trochammina
rainwateri, which are rare in Levy County. The zone as identified in
Levy County consists of gray, micaceous, calcareous sand that overlies
a dark gray, fissile, calcareous shale and shaly limestone, containing thin
seams oW gray to cream, shaly limestone, flecks of lignite and traces of
gypsum. ieomum-gray, calcareous, quartz sandstone with thin shale
partings and a coarse sand and gravel conglomerate are irregularly
interbedded with the shale.

The following wells;6 penetrated the Atkinson formation in Levy
County:
W-355: Florida Oil Discovery- Sholtz well
Atkinson formation
"A Zone" 4,010 to 4,152 feet
"B Zone" 4,152 to 4,254 feet
W-1007. Sun Goethe well
Atkinson formation
"A Zone" 3,653 to 3,845 feet
"B Zone" 3,845 to 3,893 feet
W-1537: Coastal Ragland well
Atkinson formation
"A Zone" 4,121 to 4,243 feet
"B Zone" 4,243 to 4,347 feet


t"Locations given on page 76.





FLORIDA GEOLOGICAL SURVEY BULLETIN 33


W-2012: Humble Robinson well
Atkinson formation
"A Zone" 3,932 to 4,178 feet
"B Zone" 4,178 to 4,300 feet

BEDS OF AUSTIN AGE
Applin and Applin (1944, pp. 1715-1716) recognized three poorly
defined faces in the beds of Austin age in Florida. These facies are
predominately shales and sands in western and northern Florida, shale
and marly limestone in central Florida and limestones in southern
Florida. These writers reported that the beds of Austin age in northern
and western Florida are composed of marly sales, fine-grained, argil-
laceous sandstone; sandy, micaceous clay; and some limestone. The
limestone contains an occasional lens of black to brownish-black "speck-
led" shale, characteristic of the lower part of the Austin chalk of parts of
Texas. In central Florida the unit is characteristically gray to greenish-
gray, marly shale with streaks of limestone and a few fine-grained sand
lenses, and contain lenses of the "speckled" shale. Both of these facies con-
tain an abundant microfauna. Hard white limestone compose the beds
of Austin age in the southern Peninsula.
Five wells penetrated beds of Austin age in Levy County. The top
of the Austin equivalent in this report is placed at the first shaly chalk
below the Taylor equivalent, and has been picked by the electric charac-
teristics and checked by cores and cuttings in all wells except the Florida
Oil Discovery and Suwannee Petroleum wells from which only irregular
samples were available. The thickness ranges from 480 feet in the Hum-
ble-Robinson well, 490 feet in the Sun-Goethe well, to 527 feet in the
Coastal-Ragland well.
The Austin equivalent of Citrus and Levy counties can be divided
roughly into three parts. The upper 200-300 feet is light-green, cream,
tan and gray, rather tight, shaly chalk that contains medium-gray marl
and shale seams. The middle 100-200 feet is light-gray, speckled, fairly
dense chalk. The basal 100-150 feet is a gray to cream, dense chalk with
a flaky fracture and thick beds and seams of calcareous shale; gray, cal-
careous sand; and lignitic shale. The top of the Austin equivalent is
dolomitized in the Humble-Robinson well.

The upper and middle portions are correlated with the Selma chalk
and the basal section with the upper part of the restricted Eutaw sands
of Alabama, by some workers. The basal beds have very definite and
characteristic potentials and resistivities on electric logs.





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


The intervals in the following wells are assigned to the beds of
Austin age:
W-166: Suwannee Petroleum Corporation, Sholtz well No. 1
NE3 NWM Sec. 16, T. 15 S., R. 13 E.
Austin equivalent combined with W-355 Irregular samples
W-355: Florida Oil Discovery- Sholtz well17
Austin equivalent: 3,690 to 4,010 feet
W-1007: Sun Goethe well
Austin equivalent: 3,1.63 to 3,653 feet
W-1537: Coastal Ragland well
Austin equivalent: 3,594 to 4,121 feet
W-2012: Humble Robinson well
Austin equivalent: 3,452 to 3,932 feet

BEDS OF TAYLOR AGE
The Taylor equivalent in Citrus and Levy counties is a fairly thick
and consistent section composed of white to cream chalk separated by
thin beds and seams of tan, crystalline dolomite and characterized by
fragments of Inoceramus sp. and Torreina sp.
Three thin beds in the base of these deposits make a very distinctive
pattern on the electric logs, the resistivity and potential both being low.
These patterns are particularly well-developed at depths of 3,338 feet,
3,348 feet, and 3,357 feet in the Coastal-Ragland well. Because the po-
tential is flat throughout most of the Upper Cretaceous of peninsular
Florida, these strong depressions are very prominent in the potential.
These beds are widely developed although only 1 to 2 feet thick, and
are believed to be a series of clay beds, probably ash falls. The beds are
present in almost all of the wells that penetrate the basal Taylor beds in
peninsular Florida and make a very good correlation point between
these wells and provide a very suitable contouring horizon for the Upper
Cretaceous, see the structural map of figure 16. Because the clay beds
are so thin, the sediments are rarely recovered in rock cuttings, but
occasional fragments of greenish-gray to light-gray, fissile, waxy shale
and of brown calcareous clay in the cuttings at depths corresponding to
these electric patterns are believed to represent the beds.
In the thick section of chalk of the lower Lawson limestone and Tay-
lor equivalents, and the gradual change in faunal content of the two
sections, the top of the Taylor is placed by some workers at the first
occurrence of abundant fragments of Inoceramus sp. This top has proved
to be highly variable, even in closely spaced wells, and the Taylor equiva-
17Locations of wells given on page 76.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


lent has been identified in this report through its rather distinctive elec-
tric log characteristics. The top is indicated by a series of strong and
evenly spaced resistivities separated by chalk line resistance as observed
on the electric logs as follows: 2,892 feet in the Coastal-Ragland, 2,780
feet in the Humble-Robinson, and 2,535 feet in the Sun-Goethe. These dis-
tinctive features are referred to rather generally by geologists as "Taylor
kicks".
The Taylor equivalent is present from depths of 2,892 to 3,594 feet
m the Coastal-Ragland well, a thickness of 702 feet; from depths of 3,092
to 3,690 feet in the Florida Oil Discovery-Sholtz well and the Suwannee-
Sholtz well, a thickness of 598 feet; from depths of 2,780 to 3,452 feet
in the Humble-Robinson well, a thickness of 672 feet; from depths of
2,535 to 3,163 feet in the Sun-Goethe well, a thickness of 628 feet.

LAWSON LIMESTONE (NAVARRO EQUIVALENT)
The Lawson limestone was described and named by the Applins
(1944, p. 1708) for the late Upper Cretaceous beds and the name is taken
from the J. S. Cosden-Lawson well No. 1, Marion County, Section 25,
Township 13 South, Range 20 East. The formation includes two mem-
bers, an upper and lower. The name was proposed for:
"A limestone faces of the late Upper Cretaceous occurring in northeast Flor-
ida and the peninsula below the Cedar Keys limestone and above beds
of Taylor age."
In Levy County the Lawson limestone is also separable into an upper
and a lower member, each with a distinctive fauna. The upper member
is a cream-colored, fragmental, marine limestone with gypsum lenses and
porosity impregnation. The lower member is commonly cream to white,
pasty, marine chalk and fragmental limestone. The Applins (1944, pp.
1708-1709) recorded that an undescribed Rotalid sp., Vaughanina sp.,
Orbitoides sp. and Pseudorbitoides? sp., are present in the upper mem-
ber, and that the lower member is characterized by Lepidorbitoides sp.,
L. (Asterorbis) aquayoi D. K. Palmer, L. (Asterorbis) rooki Vaughan
and Cole, and Sulcoperculina lawsoni Applin and Jordan.
The term Lawson limestone has been accepted by most southeastern
geologists. The lower member is clearly Cretaceous in age and correlates
with the Cretaceous of Cuba, Mexico and Europe, and occupies the same
stratigraphic horizon as plastic beds of Navarro age of western Florida,
Alabama and Mississippi.
The upper member was defined as late Upper Cretaceous, but in
recent oil tests, particularly, the Humble-Hodges well No. 1, in Taylor





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


County, the fauna characterizing the member occurs very high in the
section in an interval normally considered to be Cedar Keys formation,
of Paleocene age. This additional information indicates that the upper
Lawson is a transitional bed including fossils characterizing both Paleo-
cene and Cretaceous, but since characteristic Cretaceous fossils, particu-
larly species of Pseudorbitoides sp., Torreina sp., Orbitoides sp., and
Vaughanina sp., are present in the bed it is considered to represent ths
top of the Cretaceous in peninsular Florida by most writers.
The Lawson limestone was identified from rock cuttings from seven
wells in Levy County. The top of the upper Lawson is marked by a very
definite and characteristic cream-colored, porous, granular, sub-6olitic,
marine, fragmental dolomite. The upper few feet is extremely fossiliferous
being a coquina of Applin's Rotalid sp., Pseudocyclammina sp., and
Pseudorbitoides sp., loosely cemented together and greatly altered by
dolomitization. This extremely fossiliferous zone is thin and the lower
part of the upper Lawson is similar to the upper part lithologically but
is less fossiliferous.
The lower Lawson is a pasty to fragmental, marine, chalky lime-
stone, frequently dolomitized. Torreina sp., Sulcoperculina cosdeni Ap-
plin and Jordan, several species of Lepidorbitoides and Cibicides harper
(Sandridge) characterize the bed. Speciments of Lepidorbitoides are
quite common.
Gypsum is rare to common throughout the upper Lawson, occurring
as impregnations of the porosity, but is rare in the lower Lawson. Some
carbonaceous partings are present in the lower Lawson, but these are
absent in the upper.
The Applins (1944, p. 1739) assigned only 42 feet of the section in
the Florida Oil Discovery-Sholtz well to the upper Lawson limestone.
This appears thin for the formation because 173 feet of this member was
cut by the Coastal-Ragland well, located about a mile south of the Sholtz.
The top of the Cretaceous is believed to be obscured in dolomite in the
Sholtz well. The formation thins from west to east in Levy County, being
612 feet thick in the Coastal-Ragland well and only 345 feet in the Sun-
Goethe well, see figure 16.
The Lawson limestone was penetrated by the Suwannee Petroleum-
Sholtz well and the Florida Oil Discovery-Sholtz well but poor sampling
prevents exact identification. The formation is present in the following
wells as tabulated:






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


W-1007: Sun Goethe well
Lawson limestone
Upper: 2,190 to 2,280 feet
Lower: 2,280 to 2,535 feet
W-1537: Coastal Ragland well
Lawson limestone
Upper: 2,280 to 2,453 feet
Lower: 2,453 to 2,892 feet
W-2010: C. M. Brukenfeld, Assoc.,
Levy-Lennon Syndicate, Inc., well No. 1
NE% NW, Sec. 5, T. 14 S., R. 16 E.
Lawson limestone
Upper: 2,010 to 2,120 feet (T. D.)
W-2012: Humble Robinson well
Lawson limestone
Upper: 2,290 to 2,420 feet
Lower: 2,420 to 2,780 feet
W-2166: J. A. Abbott, Prudential Lumber Company well No. 1
NW4 SE3 Sec. 34, T. 13 S., R. 16 E.
Lawson limestone
Upper: 1,935 to 1,945 (T. D.)

CENOZOIC ERA
TERTIARY SYSTEM

PALEOCENE SERIES
CEDAR KEYS FORMATION
Terminology: The Cedar Keys formation was proposed by Cole (1944,
pp. 27-28) for tan-colored, hard limestones which contain Borelis gunteri
Cole and Borelis floridanus Cole in their upper portion, and being spar-
ingly fossiliferous or unfossiliferous in the lower. As used by Cole, the
formation extended from the uppermost occurrence of the Borelis fauna
to the top of the Upper Cretaceous, as identified by him, and included
a thin transition zone at the base which is considered by most south-
eastern geologists to represent the top of the Upper Cretaceous, being
the upper member of the Lawson limestone.
The Cedar Keys formation, as used in this report, covers the interval
extending from the top of the Borelis fauna, the first occurrence of small
foraminifers associated with Borelis, or the top of a characteristic lith-
ology to the top of the Cretaceous, which in Levy County is the upper
Lawson limestone. Cole's Cedar Keys formation is thus expanded by
the inclusion of an indefinite thickness of beds at the top and contracted
by the exclusions of the upper Lawson limestone. The Applins (1944, p.
1704) applied the name Cedar Keys limestone to a similar interval, and





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


with this usage the formation is much more uniform in its occurrence
and thickness, than as formerly defined. The Florida Geological Survey
has accepted the new definition but retains the original name for this
formation.
The bed is characterized by the two species of Borelis, Cribrospira?
bushnellensis Applin and Jordan, Planispirina? kissengenensis Applin and
Jordan, Valvulammina nassauensis Applin and Jordan, and by two ostra-
cods, Cytherella symmetrica Alexander and Cythereis sp. aff. C. sculptilis
Alexander which according to the Applins (1944, p. 1704-05) suggest a
slight relationship to the Midway beds of the western Gulf Coast.
The formation is widely developed throughout most of peninsular
Florida and is considered the marine equivalent of the plastic facies of
the southeastern states to which the term Midway group has been ap-
plied. It lies below a definite Salt Mountain fauna of lower Eocene,
Wilcox age and conformably upon transitional Upper Cretaceous beds.
It thus occupies the interval represented elsewhere by the beds of Mid-
way age.
Lithology: The Paleocene of peninsular Florida is white, cream and
gray, pasty to fragmental limestones, which have rare lenses of 6olitic
limestone. The porosity of the rock is impregnated by gypsum, giving
it a speckled appearance.
The top of the Cedar Keys formation is commonly dolomitized and
unfossiliferous. The chalky appearance of this dolomite, however, con-
trasts strongly with the crystalline, flaky dolomite of the basal Oldsmar
limestone. Placing this dolomite in the Cedar Keys formation is sub-
stantiated by rare molds of Borelis sp. found in this interval in at least
one well, the Abbott-Prudential well. Thin clay lenses and pyrite con-
centrations occur at the top rarely and almost complete porosity filling
by gypsum sometimes marks the top of the formation.
The Cedar Keys formation of Levy County is composed of inter-
bedded tan to gray, finely granular, fragmental, often very fossiliferous
limestone and tan to brown, finely crystalline to chalky textured dolo-
mite. Gypsum has completely impregnated the porosity of large sections
and occurs irregularly as thin lenses. The limestone is rarely fossiliferous
near the top and is dolomitized. The lower portion is more fossiliferous
and some beds are essentially composed of specimens of microfaunas
held in a pasty limestone matrix. Fossils characterizing the bed else-
where in peninsular Florida are present and are abundant in these un-
altered limestones.






FLORIDA GEOLOGICAL SURVEY -BULLETIN 33


Thickness: The Cedar Keys formation is only slightly thinner in eastern-
central than in western Levy County but it can be presumed to thin
toward the Peninsular arch in northern and eastern Florida, that part of
the State having been structurally high during the Paleocene. The
formation is 600 feet thick in the Coastal-Ragland well, in western Levy
County, and 540 feet in the Humble-Robinson well, 713 feet in the Sun-
Goethe well, 550 feet in the Brukenfeld-Levy-Lennon well, and 445 feet
in the Abbott-Prudential Timber well in eastern central Levy County.


The Cedar Keys formation was identified at
under the following wells:
W-166 and W-355: Florida Oil Discovery-Sholtz and
Sholtz wells samples combined.
Cedar Keys formation: 1,636? to ? feet
W-1007: Sun-Goethe well
Cedar Keys formation: 1,658 to 2,190 feet
W-1537: Coastal-Ragland well
Cedar Keys formation: 1,680 to 2,280 feet
W-2010: Brukenfeld-Levy-Lennon well
Cedar Keys formation: 1,460 to 2,010 feet
W-2012: Humble-Robinson well
Cedar Keys formation: 1,750 to 2,290 feet
W-2166: Abbott-Prudential well
Cedar Keys formation: 1,335 to 1,935 feet


the depths tabulated


Suwannee Petroleum-


EOCENE SERIES
Lower Eocene

OLDSMAR LIMESTONE
The Oldsmar limestone was used by the Applins (1944, p. 1699) to,
"include the interval that is marked at the top by the presence of abundant
specimens of Helicostegina gyralis Barker and Grimsdale, and that rests on
the Cedar Keys limestone."
The formation was separated into four faunal zones, which in descend-
ing order were as follows:
Zone 1: Helicostegina gyralis
Zone 2: Salt Mountain faunal unit, characterized in the
Peninsula by Pseudophragmina cedarkeysensis Cole.
Zone 3: Coskinolina elongata Cole
Zone 4: Unnamed, characterized over the northern Peninsula
by Miscellanea nassauensis Applin and Jordan and





GEOLOGY OF CITRUS AND LEVY COUNTIES, FLORIDA


over the central and southern Peninsula by Lock-
hartia cushmani Applin and Jordan.
The Oldsmar limestone as erected by the Applins is predominately a
series of faunal zones and is not different lithologically from the over-
lying and underlying formations. It is composed essentially of frag-
mental marine limestones, partially to completely dolomitized and con-
taining irregular and rare lenses of chert, impregnations of gypsum and
thin shale beds. Fossils are common but sometimes dolomitized and
poorly preserved.
The limestone and dolomite of lower Eocene age of peninsular Flor-
ida, the Oldsmar limestone, grades westerly and northerly into a elastic
faces, greenish-gray clay and variegated, micaceous, glauconitic, sandy,
carbonaceous clays containing several highly fossiliferous zones, the
faunas having been identified as those of Wilcox age. A few species oc-
curring in the Salt Mountain reef limestone of Wilcox age in Clarke
County, Alabama, occur in the limestone of the Peninsula, and the cor-
relation is made more exact.
Thickness: The thickness of the Oldsmar limestone is variable, the
top of the formation being identified by the first occurrence of Helicos-
tegina gyralis. In a thick section of limestone of fairly uniform lithologic
characteristics in which the original texture of the rock and the fauna
have been destroyed or altered by partial or complete dolomitization, an
irregular thickness is to be expected. This dolomitization, combined with
the irregularities of fossil occurrences, introduce additional variations in
thickness. The formation, or rather faunal zone, is 380 feet thick in the
Coastal-Ragland well, in western Levy County and 500 feet thick in the
Humble-Robinson well, 568 feet in the Sun-Goethe well, 550 feet thick
in the Brukenfeld-Levy-Lennon well, and 445 feet in the Abbott-Pru-
dential well of central Levy County. No wells penetrated the Oldsmar
in Citrus County.

Lithology: The Oldsmar was penetrated by seven oil tests in Levy
County, but no wells have been drilled in Citrus County that pene-
trated sufficiently deep to encounter the formation.

The Oldsmar limestone is marked by the presence of Helicostegina
gyralis in brown, very porous, friable, granular limestone composed of
calcite grains loosely imbedded in limestone paste. This limestone is
interbedded with brown, coarsely crystalline, sugary, porous dolomite
containing seams of white chert and anhydrite; thick beds of coffee-
colored, dense chert; and finely crystalline, tan to brown dolomite. The




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