Geology of Escambia and Santa Rosa Counties, western Florida Panhandle ( FGS: Bulletin 46 )

SrATE F MLORIDA
TrATE BOARD LW X VATIOW
DIVEMN W OLO

Robdt 0, VTawm, Dbemb

BY IF
Own T. -Ma t

GEOLOGY OF ESCAMBIA
AND SANTA ROSA COUNTIES
WESTERN FLORIDA PANHANDLE

Pnnd by the
UNITED STATES GEOLOMCAL SURVEY
in opratio wih thb
FllDA GEOLOGICAL SURVEY
ESCAMBIA AND SANTA RMA COUNTIES
an d oro
CrrT OF PENBACILA

TALLARHASM
wa
QE
99
.A3
no. 46

ANN S. COCRULL

STATE OF FLORIDA
STATE BOARD OF CONSERVATION
DIVISION OF GEOLOGY

FLORIDA GEOLOGICAL SURVEY
Robert 0. Vernon, Director

BULLETIN NO. 46

By
Owen T. Marsh

GEOLOGY OF ESCAMBIA
AND SANTA ROSA COUNTIES,
WESTERN FLORIDA PANHANDLE

Prepared by the
UNITED STATES GEOLOGICAL SURVEY
in cooperation with the
FLORIDA GEOLOGICAL SURVEY
ESCAMBIA AND SANTA ROSA COUNTIES,
nd the
CITY OF PENSACOLA

TALLAHASSEE
1966

FLORIDA STATE BOARD

OF

CONSERVATION

HAYDON BURNS
GoUmror

TOM ADAMS
Secrrtry of State

BROWARD WILLIAMS
Treasurer

FLOYD T. CHRISTIAN
Superintendent of Public Instruction

EARL FAIRCWLTH
Attorney Gmeeral

FRED O. DICKINSON, JR.
Comptroier

DOYLE CONNER
Commissioner of Agriculture

W. RANDOLPH HODGES
Director

LETTER OF TRANSMITTAL

FLORIDA GEOLOGICAL SURVEY
Tallahasso

Honorable Haydon Burnr, Chairman
Florids State Board of Conservation
Tallhasem, Florida

Dear Governor Burns:

A report prepared by Dr. Owen T. Marsh of the U.S. Geological
Survey, in cooperation with this division will be published as Bulletin
No. 46. The report, "Geology of Escambia and Santa Rosa Counties,
Western Florida Panhandle," presents many new facts on the
stratigraphy of the arm.
We have already been able to recommend to the industry that it
try using porous and permmble limestone covered and resting upon
dense clays as a reervoir for disposing of waters from its procein
This has proved very sucvesfu and other industries ar experimenting
with this disposal method. Economic expansion asuld follow and our
water reoures will be fully protected from contamination.

Respectfully yours,
Robert O. Vernon
Director and State Geolgist

iii
6

caq.d e r~dlrox

Dr The Pa* M ria i. v.
St PenbL Frid.

iv

CONTENTS

Pale

A atn ct .....
Introduction .
GermPl stae .
Iloation and deription of ar ............

Topography and drainage
Clim ate ................ .
Regional geologic Wetting .............. ...... .....
Scope and methods of investigation ................
Drilling methods and reliability of samples ....
Previous work ... .........

Acknowledgments .
Stratigaaphy ...........
Tertiary System ......

Lower Eocene
Wilcox Group .....
Hatchetigbee Formation ......
Type ocality
Distribution and thicknMs .
Litbology and fosslm
Cotacts and ectric-log express~ on
Middle Eocene -.
Clariborne Group .
CUiTbaom Groupr t ....... ....................
Tallahata Formation
Type locality
Distribution and thickness ...... .........
Lithology and fossiti ........... .......... ....
Contcts and electric-log expremon ...

Equivalent of the Lisbon Formation

Type locality ad regional variatons
Distribution and thikes ......

ConuLris and ellctric-log eiprFioin

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

.................

S . .....

I -, ......... ...

- --- - - -
. -

6 a

I
4
4
4
6

. ... 14

8

18
18
18

18
18

18
-.. 18

22
22
22
2

24
S24

246
246

27
29

''~' '

CONTENTS

Upper EF n .......... ............. .. ........... 29
Jackson 8 ...... -.. 29
Oc la i G ioup .. ....... ..- 29
Type lcality and diacumon of miniature ........._t...... 29
tribution d thi ne .......... .......... 40
Lithoogy ... . ..... ...... 41
Foami mand age -----...--. ...- ... ..- 42
Contacts sa electric-log expreon ..... .- 42
Middir Oligtocr e ...45
Vicksburg Group ........ ......... 45
Bucatunna Clay Member of the Byram Formation .. 45
Type locality and history of nomencLature ......- ...-- 45
Distribution and thickness .. ..... ..... 46
L thology .... ............ ... ..... ..... ........... 45
Fos ils antd ag ....... .................... .. .. . 47
Contacln and electric-log expreBSion .. ......... .................. 48
Upl)lxr Oligoaene anti lower Miocene . ...................... ....... 48
(ihickanawhay Limestone and Tampa Formation
undifferentiated .......--... .. .... . ........... ........ 48
Chickasawhay Lim tone ................... 49
Typr locality and history of nomenclatur ............ 49
Distribution, thickness and lithology 49
Fnoils and age ........ ... 49
('ontcts and electric-log expre ..on......... 50
Tampa Frmation ...... .. 50
Typr lrocaity and history of nnmenclaturr 50
Distribution and thicdness 51
Lithology ..... 51
Frnwls and age .... 52
Contacts and electric-lot expr n ............. 53
Middle and upper Micn ..4
Prmcoula Clay ... 54
Type klcality .._ ..... 54

Dtribution and thickmne
Litho y -.o
Sample logs of type well~
Fowsis ad age ...
Correlation
'onlwats
leclric-log tepreswion
iocrrne coarse clastics
Dintrbution and thickness
Litholgy
Fuails andi age
contacts and electric-log expression
Quaternary (?) System
Plei tocene(?) Series .......
('itronllie Formation ..
TyIn locality ...........
D istribution ......... .
Thickness .
Lit hology
1nwMils .. ...
Age of the Citronelle Formation
('Cntacts and electric-log expreiuin
Quaternary System
Pleatancen Series .
Marine terrawe deposits
Pleifstirmer manrne terraces and paleagegraphy
Structure
Regional (hip
(ontemporaneous faulting
E rwnomi geology
CGround walker
Prtrowlcm
Clay

vii

CONTENTS

Page

54
57
59
63
67

67
So
68
09
69
70
73
74
74
74
........ 74
--. -- 74
75
75
81
86
87
87
87
87

88

94

96
103
10a
104
105

Paw

SaM anu d grvl --..- ............ 10
Appentdiceo
Appftdix A: Lit of wels used in this report .. 06
AppMnix B: l~o~ of sdtted cwll in wmaNrnmxt
lo~ d amd soutbwester Alabama .._ 111
Ap~ xdi C- Lst of foail polLen mm the Citruaelr Fuormtion
of Emsnm and Sata Rosa Counties Florida .. 132
ef nmce. .......... ...... ....... 135

viii

ILLUSTRATIONS

Figu nr Page

I. Map showing location and regional geologic setting of Escambia
and Santa Rosa counties ......................... .... ..... 5
2. Generalized geologic column of formations in the
western Florida Panhandle . ................. ......... ... .. 10
3. Geologic section (Q-Q') from Mobile Bay to the
Choctawhatchee River ....... .................................. 11
4. Map showing locations of cross sections and wells used in this report 13
5. Fence diagram or geologic formations beneath Escambia and
Santa Rosa counties . ......... .............. ..... ----...-----..........-...- Facing 18
6. Geologic section B-B' across Escambia and Santa Rosa counties ....,.... 19
7. Geologic section C-C' across Escambia and Santa Rosa counties .......... 20
8. Geologic section D-D' across Escambia and Santa Rosa counties .......... 21
9. Geologic section E-E' across Escambia and Santa Rosa counties ....---- 23
o0. Geologic section F-F* across Escambia and Santa Rosa counties ........ 26
11. Contours on top of the Ocala Group in westernmost Florida ................... 41
12. Isopachous map of the Bucatunna Clay Member of Byram Formation 48
13. Isopachous map of the Pensacola Clay .......... .................................... 65
14. Electric-log correlation of the three type wells of the Pensacola Clay.... 66
15. Electric logs of selected oil test wells ..................... .... ............................ 57
16. Contours on top of the Pensacola Clay .......................................- ............... 58
17. Contours on top of the Miocene beds in westernmost Florida .......... 73
18. Facies changes in the upper part of the Citronelle Formation ....... 76
19. Hardpan layers in the Citronelle Formation. Baldwin and
Escambia counties. Alabama ........... .............. .....77 & 78
20. Section of Citronelle Formation exposed in bank of Coldwater River,
showing location of pollen sample D1379 ................ ..................... ..84
21. Topographic profiles across the western end of the Florida
Panhandle ............................................... ................. ..... .. .. . 90
22. Extent of the Penholoway sea along the coast of westernmost Florida 93
23. Extent of the Pamlica sea along the coast of westernmost Florida 95
24. Faulting in northern Escambia and Santa Rosa counties,
Florida, and southern Escambia County. Alabama ..... ................ 97
25, Diagram of recurrent movement on Foshee fault between
wells W -3321 and W -1602 . .............. ............ ............. .. 99
26. Section M-M' showing displacements along the Jay and Pollard
faults in northwestern Santa Rosa County ...... .............. 100

ix

M I

IuISTrrATIoNS

Fiure PaW

27. Swcio N-N' showing diMAenm lonr the Pollard and Pahe
faults in northern Santa Roum Couny .100
28, Gravity anomalies in Ecamnbia and Santa Ro counties, Florida ...... 102

PLATES

1. Fomib from the Lisbo equivuml t Chikauwhay Lnntmm.
and Mio.nr ra-rwe ti --....... -- 0
2. McdImuskL fr the Tamps Formation mIn Miocene cowa cldtic 32
8 FowiU Imm the Lisbon quivlent Tamps Formationa Pen l
Clay. and Mioceme oarmw dlati -.. -- .- ..... ........ 34
4. ForaminifPrs rom lower member of the Peon col Clay ...--- 6
S. Foraminlfera from lower member of the Penucola Clay ..... ............... 38

TABLES

Table Paw

1. Framiniiferr fxund in the LUhon equivalent in Eaambia.
Santa RoMe and Okallom counties Florida 28
2 Foraminifera found in thr Ocala Group in Enambia. Sanlt Rona
and Okalooms counties. Florida .. ...... .. .. ......... -. 43
3. Foraminifera found in the Bucatunn Clay Member ao t1h
Byram Formalion, Santa oRa County, Florida .................. .............. 47
4. Molluskn found in the Tumam Formation in Santa Rosn and
Escambia counties. Florid ..... .. ........ . 53
5. Foraminifera found in the Tampa Formation in Escamhia,
Santa RIMs. and Okalo ma counties Florida ._ ..... 53
6 Br strati rphic distribution Ifaccordin to Puri. 19531 of Fora-
minifer found in the lower member of the Pensacola (lay in
E- anbi, Santa Ra4 and Okahoxsm counting. Florida 64
7. Additional species of Foraminifera fIrn the lower memier of the
PetaEola Clay, found in cuttings m well W-3225. southern
OkaooM Coauy .. ........ ..... 66
8 Biostrtigrphui distribution according to Puri, I953a) of Fora-
minifera found in the E nmhbia Sand Member of the Penucola
Clay in Sant Roa County, Florida, and Baldwin County. Alabama .... 66

TABLES

Table Page

9. Biostratigralhic distribution laccurding to Puri, 1953a) nf Fora-
minifera found in the upper member of the Pensacola Clay in
Escambia and Santa Rosa counties, Florida, and Baldwin County,
Alabama ,.......... ....... 66
10. Biostratigraphic distribution (according to Puri, 1953a) of Fura-
minifera found in the Miocene coarse clasties in Escamhia amn
Santa Rosa counties, Florida, and Baldwin County. Alabama ............ 71
11. CompoHitr list or mollusks found in the Miocene coarse clastics in
Escambia and Santa Rosa counties, Florida .... ... 72
12. Mollusks found in the Citronelle Formation (well W-2339) on
Fairpoint Peninsula. Santa Rosa County, Florida .. ... 85
13. Pleistocene shorelines and terraces in the Florida Panhandle ac-
cording to various authors. Elevations are above mean sea level.
Pattern at left represents worldwide advances and retreat of
glaciers . . .. . .... .... . . ~. ....~........ .... 89
14. List of well used in this report .......- ............_._.-......... Appendix A 106
15. Logs of selected wells in westernmost Florida and southwestern
Alabam a .... ...... ... .. ............ ... ..... .. ................ .......... A appendix B 111
16. List of fossil pollen from the Citronelle Formation of Escambia
and Santa Rosa counties, Florida ............. ...................... Appendix C 132

xi

I

GEOLOGY OF ESCAMBIA

AND SANTA ROSA COUNTIES,
WESTERN FLORIDA PANHANDLE

By
Owen T. Marsh

ABSTRACT

The westernmost part of the Florida Panhandle, Escambia and
Santa Rosa counties, is underlain by a thick sequence of Tertiary
sedimentary formations that dip southwestward at 30 to 40 feet per
mile. These formations are described (in ascending order) as follows.
The oldest formation studied is the Hatchetigbee Formation
(Wilcox Group, early Eocene) which consists chiefly of clay with
some shale, siltstone, and shaly limestone. At the base is the thin
Bashi Marl Member. The formation averages 315 feet in thickness.
Above the Hatchetigbee is the Tallahatta Formation (Claiborne
Group, middle Eocene), made up of calcareous shale and siltstone
with numerous beds of limestone and sand. The Tallahatta averages
255 feet in thickness within the area.
Overlying the Tallahatta is a thick section of shaly limestone that
has been correlated with the Lisbon Formation of middle Eocene age
by previous workers. However, this section differs so much in lithology
and thickness from the Lisbon at its type locality in Alabama that
it is called the Lisbon equivalent in this report. The unit is about 500
feet thick. Twenty-eight species of Foraminifera were identified from
the Lisbon equivalent.
The Ocala Group averages about 165 feet in thickness within the
area and thickens eastward across the Panhandle. The Ocala is a
light-gray to white limestone composed mainly of foraminifers, mol-
lusks, corals, and other fossils. Fifty-seven species of Foraminifera
were identified.
The Bucatunna Clay Member of the Byram Formation (Vicks-
burg Group, middle Oligocene) unconformably overlies the Ocala
Group. It thins eastward from Escambia and Santa Rosa counties,
where it averages 125 feet in thickness, and pinches out about 30
miles east of the area. The Bucatunna is a dark-gray, soft, silty to

1

U i

FLORIDA GEOLOGICAL SURVEY-BULLETIN No. 46

sandy clay. Although fossils are scarce in the Bucatunna, 26 species of
Foraminifera were identified.
The Chickasawhay Limestone (upper Oligocene) and Tampa
Formation (lower Miocene) are not distinct enough in the western
Panhandle to be separated except in a few localities and are therefore
shown on geologic sections as undifferentiated. The Chickasawhay
consists of gray vesicular limestone and dolomitic limestone with
some light-brown dolomite. The Tampa is hard, gray to white, and
generally not dolomitic. The Chickasawhay underlies the entire area,
thickening gulfward from about 30 to 130 feet; the Tampa, however, is
present only in the southern half of the area where it has a maximum
thickness of 270 feet.
The Pensacola Clay, a new formation of late middle to early late
Miocene age, comprises three members: a lower member and an upper
member of gray sandy clay, separated by the thin Escambia Sand
Member. The formation does not crop out, and it interfingers east-
ward and northward with the Miocene coarse plastics. Westward the
Pensacola Clay continues at least as far as Mobile Bay where it
reaches its maximum known thickness of more than 1,000 feet. In
places thick shell beds occur near the top of the upper member. Sixty
species of Foraminifera were identified from the formation.
Beds of brown to gray, poorly sorted sand and gravel with thick
lenses of clay rest upon the Pensacola Clay in the southern part of
the area and upon the Chickasawhay Limestone in the northern part.
These beds cannot be satisfactorily correlated with known forma-
tions, and pending further study they are here referred to as the
Miocene coarse plastics. The unit is of middle to late Miocene age.
The Citronelle Formation of Pleistocene(?) age unconformably
overlies the Miocene coarse plastics. The two units are lithologically
similar except for the abundance of shells in the latter and their
virtual absence from the former. The Citronelle probably ranges
roughly from 40 to nearly 800 feet in thickness in westernmost
Florida; however, a veneer of marine terrace deposits that caps the
Citronelle and which is indistinguishable from it except in a few
places makes precise measurement impossible. The Citronelle con-
tains layers of hardpan, fossil wood, a few shells, and kaolinitic bur-
rows of aquatic animals. A Pleistocene age is suggested by the fresh-
ness of the fossil wood and by two samples of fossil pollen dated as
Quaternary.
A series of topographic profiles across the area suggests that
three marine surfaces of Pleistocene age can be recognized in Escam-

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 3

bia and Santa Rosa counties: The Pamlico terrace with shore line at
30 feet, the Penholoway terrace with shore line at 70 feet, and a sea-
ward-sloping upland surface whose altitude ranges from about 70 to
270 feet. The latter is by far the most extensive of the three surfaces.
Paleogeographic maps are presented to show the approximate extent
of the Pamlico and Penholoway seas.
Structurally the area is a simple homocline without folds or faults
except in the north-central part where the step-faulted Pollard graben
extends into the area from the north. The graben is bounded on the
east by the Foshee fault and on the west by the Pollard, South Pol-
lard, and Jay faults. Repeated movement contemporaneous with de-
position has occurred on all these faults at least from Late Cretaceous
to late Oligocene time. This has caused thickening of beds in the
downthrown blocks compared with the same beds in the upthrown
blocks; and as a result, the stratigraphic throw of these faults in-
creases with depth. Most of the movement on the Foshee fault
apparently occurred during Late Cretaceous-early Paleocene time. A
reasonable hypothesis for the origin of the graben is that crustal col-
lapse resulted from lateral flowage of salt, derived from the Louann
Salt of Jurassic(?) age, at great depths beneath the area, periodically
stimulated by sedimentary loading during subsidence of the Gulf
Coast geosyncline. The nature of the faulting, the proximity and
trend of the Mississippi Interior Salt Dome Basin, and negative
gravity anomalies in western Florida and southern Alabama support
this hypothesis. If salt is present, it probably lies at a depth of about
19,000 feet, judging from the depth at which the Louann Salt(?) was
penetrated in a well at Citronelle, Alabama.
The most important natural resource of economic interest in the
area is ground water. Escambia and Santa Rosa counties enjoy an
abundant supply of the softest and least mineralized ground water
in Florida-an important factor in industrialization of the area.
Other resources include deposits of clay suitable for making ceramics
and brick, and large quantities of sand and gravel for road building.
At the Pollard oil field just north of the area, oil is produced from
traps in the Tuscaloosa Formation of Late Cretaceous age, both on the
upthrown and downthrown sides of the Pollard fault. In Escambia and
Santa Rosa counties numerous test wells have been drilled into these
beds in hopes of striking oil, but without success. However, the possi-
bility of oil in Lower Cretaceous strata has been only slightly explored.

FLORIDA GEOLOGICAL SURVEY -BULLETIN No. 46

INTRODUCTION
GENERAL STATEMENT
As a result of investigations by both the State and Federal Geolog-
ical Surveys, the succession of geologic formations in most of Florida
is fairly well known. Until recently, however, little was known about
the geology of the western part of the Florida Panhandle. In 1958,
the U. S. Geological Survey in cooperation with the Florida Geologi-
cal Survey, Escambia and Santa Rosa counties, and the city of
Pensacola began a detailed study of the water resources of Escambia
and Santa Rosa counties, Florida. This investigation produced a large
amount of new geologic data that warranted publication as a sep-
arate report. The present report thus gives a more comprehensive
treatment of the geology than would be appropriate in a report on the
water resources of the area.
The area described in this report includes Eacambia and Santa
Rosa counties, Florida and is economically important in two major
respects. Situated at the east edge of the highly productive Gulf
Coast oil-producing region, with which it has much in common
geologically, it is a frontier area for oil exploration. Producing oil
fields at Pollard, South Carleton, and Citronelle, Alabama lie 3 miles
north, 21 miles northwest, and 40 miles west of the area, respectively.
The alignment of these fields trends directly towards the area of this
report. No less important economically are the water resources of
the area. Large supplies of exceptionally soft and unmineralized
ground water have attracted to the area more than half a dozen major
industries which manufacture synthetic fibers, paper, and chemicals.
The largest industry is a plant in Escambia County which employs
about 6,500 persons and is the world's largest producer of nylon yar
from raw materials. In addition, two large military bases are located
in the southern part of the area: the Pensacola Naval Air Station and
part of the Eglin Air Force Base.

LOCATION AND DESCRIPTION OF AREA
The area described in this report consists of Escambia and Santa
Rosa counties, the two westernmost counties in the Florida Pan-
handle, as shown in figure 1. It is bounded on the north and west by
Alabama, on the east by Okaloosa County, Florida, and on the south
by the Gulf of Mexico. Escambia County is separated from Santa
Rosa County on the east by the Escambia River and from Alabama
on the west by the Perdido River (p. 13). Santa Rosa County is the

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA

Figure 1.--Map showing kwation and regional geologic setting of Escambia
and Santa Rosa counties. Florida.

larger, but less populous, with 1,151 square miles and a population in
1960 of 29,547. Its county seat and largest town is Milton. Escambia
County covers 759 square miles, and in 1960 had a population of
173,829. Its county seat is Pensacola, the largest city in the Florida
Panhandle, with a population of 56,752.
The northern half of the area is chiefly agricultural. The principal
crops grown are corn, soybeans, Irish potatoes, cotton, and grain,
with tung and pecan trees providing additional income. About 80
per cent of the area is covered with pine forests which thrive on the
sandy soil. Huge tracts of forest are owned by a paper company which

FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

operates a large plant in central Escambia County. In contrast, the
southern half of the area is heavily industrialized. Large plants near
Milton and Pensacola produce synthetic fibers, chemicals, and paper.
Pensacola is situated on one of the largest natural harbors in the
State, and is an important seaport for shipping and commercial
fishing.
The area of this report is covered by the following U. S. Geological
Survey 15-minute quadrangles: Dyas, Ala.-Fla. (1944); Century, Fla.
(1941); Jay, Fla. (1943); Munson, Fla. (1950); Muscogee, Fla-Ala.
(1941); Milton, Fla, (1941); Harold, Fla. (1938); Fort Barrancas,
Fla.-Ala. (1941); Pensacola, Fla. (1941); and Holley, Fla. (1938).
These maps are at a scale of 1:62,500 and have a contour interval of
10 feet.

TOPOGRAPHY AND DRAINAGE
Escambia and Santa Rosa counties lie in the Coastal Plain
Province, a major physiographic division of the United States that
extends eastward from Texas and northward as far as New York. The
Coastal Plain is underlain chiefly by beds of sand, silt, limestone, and
clay that dip gently seaward. Most of these sediments were deposited
during higher stands of the sea. From the Florida Panhandle the
Coastal Plain extends inland about 160 to 200 miles. Cooke (1945,
fig. 3) indicates two topographic subdivisions of the Coastal Plain in
Escambia and Santa Rosa counties; the Coastal Lowlands, consisting
of relatively undissected, nearly level plains lying less than 100 feet
above sea level; and the Western Highland, consisting of a southward-
sloping plateau whose surface has been incised by numerous streams.
The topographic relief of the area is relatively great, compared to
most of Florida, attaining a maximum altitude of 290 feet in northern
Santa Rosa County. Most of the area lies within the Western High-
lands, the Coastal Lowlands occupying a narrow strip 10 or 12 miles
wide along the coast.
The most distinctive feature of the topography is the Pleistocene
marine terraces which have been traced by previous workers along
the Gulf Coast and along much of the Atlantic Coast. Remnants of
these terraces are preserved in Escambia and Santa Rosa counties as
upland plateaus, flat-topped hills, low coastal plains, and benches
along the rivers and bays.
A well-developed network of waterways drains Escambia and
Santa Rosa counties (p. 13). The Perdido River forms the Florida-
Alabama line along the west margin of the Panhandle and flows

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 7

southward into Perdido Bay. The Escambia River, the largest stream
in the area, flows southward from Alabama on the north, dividing
Escambia County, Florida, from Santa Rosa County, and empties
into Escambia Bay. Two other principal streams, the Blackwater
River and the Yellow River, drain central Santa Rosa County and
flow southwestward into East Bay. These major streams are fed by
an extensive system of tributaries which are deeply incised into the
upland surface. The regional south to southwestward dip of the rocks
has apparently caused many streams to erode their banks more
strongly in that direction, making these banks much steeper than
those on the opposite side. An excellent example may be seen near the
junction of the east and west forks of Coldwater Creek, 11 miles north
of Milton. This process known as "homoclinal shifting" is also
apparent along the Blackwater River and the Yellow River; in both
cases the south side of the river valley is steeper than the north.
Another aspect of the drainage is the contrast between the
tributaries on the east and west sides of the Escambia River, north
of Molino. Those on the east side are relatively short with a random,
dendritic pattern. The streams on the west side are many times longer
and have fairly straight, parallel channels that trend southeastward,
reminiscent of trellis drainage. Possibly these streams are controlled
by a local set of joints that trend southeastward across northern
Escambia County, or possibly they are controlled by the strike of dif-
ferent lithologies in the Citronelle Formation. The southeastward
trend of parts of Pond Creek, Clear Creek, and the West Fork of Cold-
water Creek in Santa Rosa County may have a similar origin.
Springs give rise to innumerable small streams throughout the
area that are notched into the edges of the flat upland. These streams
commonly head in small box canyons known as "steepheads" (Sel-
lards, 1918, p. 27). The headwalls of the gullies are maintained at a
steep angle because undermining at their base by the springs is more
rapid than erosion of the rims. Many of the springs at the heads of
these steepheads appear to be localized along extensive layers of clay
or hardpan. Good examples of such steepheads are found on the Eglin
Air Force Base in southeastern Santa Rosa County where the head-
waters of many small streams are at nearly the same altitude, about
50 feet above sea level. The largest spring in the two-county area is
Chumuckla Mineral Springs in northwest Santa Rosa County, on
the east side of the Escambia River. In 1942, this spring flowed at
nearly 50 gallons per minute.
Hundreds of small ponds dot Escambia and Santa Rosa counties,

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

the largest of which is Forty Acre Pond in north-central Santa Rosa
County. These ponds are apparently accumulations of rainwater held
up by underlying layers of clay or iron-cemented sandstone ("hard-
pan").
Santa Rosa Island, which forms the south border of the area, is
an excellent example of an offshore bar. It extends eastward nearly
48 miles from the mouth of Pensacola Bay to the mouth of Chocta-
whatchee Bay. The island is about half a mile wide and has sand dunes
as much as 50 feet above sea level. Santa Rosa Sound, between the
island and the mainland, is part of the Intracoastal Waterway.

CLIMATE
Western Florida has a humid, warm-temperate climate. Sum-
mers are warm and long, averaging about 80" F. at Pensacola, al-
though winds from the gulf make most of the nights comfortably cool.
Winters are mild, averaging 55" F. with rare cold spells of 15" or
20. The average annual rainfall is 62 inches. March, July, August,
and September are the wettest months, and October and November
are the driest. Thundershowers of high intensity are common, with
as much as 3 or 4 inches of rainfall during an hour period. Occasional
tropical storms and hurricanes blow in from the Gulf of Mexico.

REGIONAL GEOLOGIC SETTING
Escambia and Santa Rosa counties are situated in the Coastal
Plain which consists chiefly of unconsolidated sands, limestones, silts,
and clays of Cretaceous to Recent age. The Coastal Plain covers
Louisiana, Mississippi, and Florida, as well as the southern parts of
Alabama, Georgia, and South Carolina (fig. 1). Inland from the
Florida Panhandle the Coastal Plain begins along a line connecting
Tuscaloosa, Alabama with Columbus, Georgia. North of this line the
beveled Appalachian folds and piedmont complex -igneous and
metamorphic rocks ranging in age from Precambrian to Paleozoic -
are exposed at the surface. South of the line these ancient rocks are
uncomfortably overlain by the Tuscaloosa Formation of Late Creta-
ceous age and younger sediments of the Coastal Plain which form a
southward-thickening wedge. Presumably the old mountain roots of
the Appalachian complex extend to great but unknown depths be-
neath the Florida Panhandle.
According to Howe (1936, p. 82), "The Gulf Coast region of the
United States is the landward side of the most active geosyncline in

GEOLOGY OF ESCAMBTA AND SANTA ROSA COUNTIES, FLORIDA 9

North America." "The northern border of the Gulf of Mexico," Howe
continues,
"drains the earth's second largest degradation tract. These sedi-
ments have been concentrated along a narrow zone paralleling the
present shore, and, since the beginning of the Eocene, have
accumulated to a thickness which probably exceeds 30,000 feet.
. The conclusion appears inescapable that the region of the
present coastline has been depressed under the weight of these
deposits to almost three times the present maximum depth of the
Gulf of Mexico. The major axis of the Gulf Coast geosyncline
approximately parallels the Louisiana coastline, but a transverse
structure, normally referred to as the Mississippi Embayment,
extends inland up the valley of the Mississippi. The formations
which make up the landward side of the geosyncline are all wedge-
shaped, thickening rapidly from the outcrop gulfward."
Escambia and Santa Rosa counties lie on the north flank of the
Gulf Coast geosyncline and east flank of the Mississippi Embayment.
This results in the southwestward dip which is characteristic of all
the formations in the area at least as far down as the base of the
Cretaceous deposits.
The subsurface geology of Escambia and Santa Rosa counties has
more in common with that of the central Gulf Coast of Alabama,
Mississippi, and Louisiana to the west than it does with the geology
of peninsular Florida to the east. Only two peninsular Florida units
are present within the study area: the Tampa Formation and the
Ocala Group, shown in figure 2.
Figure 3 shows how the formations in the area become shallower
toward the east, until the uppermost limestone, the Tampa, crops out
east of the Choctawhatchee River. West of the river the land surface
is underlain by sand and clay of Miocene and Pleistocene(?) age.

SCOPE AND METHODS OF INVESTIGATION
At the outset of the present investigation a reconnaissance of the
area was made in a light plane in order to note outcrops and other
features on topographic maps. Because of the gentle dip of the beds,
the only formations that crop out within the area are the Citronelle
Formation of Pleistocene(?) age and the veneer of Pleistocene terrace
deposits that caps the Citronelle. Accordingly, most of the present
study is based on subsurface information consisting of well samples,
electric logs, drillers' logs, and other data from 13 water wells deeper

0 FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

GENERALIZED

GEOLOGIC

COLUMN

OF FORMATIONS IN THE WESTERN FLORIDA PANHANDLE

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t lalrlr. I' l-.p :n:iit l IpgI L .

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T CaL= In mm1t110, I l tlth -- ag r i llrm l I h- %. I[r lATig,
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Figure 2.-Generalized geologic rolumn of formations in the western Florida
Panhandle.

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Rivrr (115 miles) showing formations along the Gulf Coast of
wetLrnm Florida

m

FLmaD GeAow lCAL SUREY BULLETIN N. 46

than 500 feet and 60 oil test oles, as shown in figure 4 and Appendix
A. Sample from 33 wells were logged during the invetiation. The
deepet formation tudied was the Hatchetigee Formation of early
Eoene age. At the hse of this formation is the very thin Bashi Marl
Member which is widely used for electri-log correlation in the Gulf
Coast.
Well samples were obtained from the Florida Geological Survey,
oil companies, and local well driller. In addition, samples were col-
lected during the investigation from shallow test wells drilled for the
U. S. Geological Survey and for private owners. Well samples were
examined with a binocular microscope and mineral percentages were
estimated by visual inspection. For uniformity of logging, the grain
size of rock samples was compared with a set of standard grains used
by the U. S. Geological Survey. This classification is given by Labee
(1961, p. 38). Dolomite and dolomitic limestone in well samples were
identified with the aid of a reagent (nitrobenzine-zoresturcinol in 2N.
NaOH) which turns blue in the presence of the magnesium ion.
During the investigation, rock ample collected at intervals of
10 to 30 feet during drilling of the wells were used to determine the
types of rock that make up the various ui T geoloc unit. The geologic
lop and electric log of the wells were compared to determine the
depth to and thickness of each unit.
The geologic section at the Pollard oi field (2 miles north of the
area) as given by Winter (1954, p. 127, fig. 3) was used as the stand-
ard for defying the tops of the Hatchetigbee and Tallahatta Forma-
tions and the Lisbon equivalent. These formations were extended
southward into the western Florida Panhandle by electric-log correla-
tion. As a check, formation tops were compared with those picked by
geologists of the California Company at Pensacola and were found to
be in virtually complete agreement with them. Most of the electric
logs used in this study were made from oil-test wells by the Schlum-
berger Well Surveying Corporation. A few electric logs of water wells
in the aea were made by the Florida Geological Survey using a Widco
logger.
Section of the Citronelle Formation and Pleistocene marine ter-
race deposit exposed in roadcuts and embankment were measured
by leveling with a Brunt compa.
In Oeder to gain a three-dimensimal impression of the regional
stratiraphy, a geologic peg model of Eacambia and Santa Rosa coun-
tie was constructed and proved to be very helpful

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA

Figure 4, Map of westernmost Flnrida and southwestern Alabama showing
locations of crross sections and wells used in this report.

FLOPIDA GIouxaICAL SuavvY BULLEIN No. 46

DRILLING METHODS AND RELIABILITY OF SAMPLES
For amne welA in the area electric logs either bad not been mde
or did not cover the first few hundred feet of the drill hole. Where
electric lgs were available, depths and thicknease had to be
determined oely from the samples. The reliability of sample depths
depends to a large extent on the method of drilling. In the western
Panhandle, the rotary method is used for nearly all but very shallow
wells and produces samples that are more or les unreliable as to
depth (Marsh, 1961). This is primarily because of two factors:
(1) the time required for the rock material to reach the surface, and
(2) caving of rock material from the sides of the drill hole. Thus,
there is usually a discrepancy between formation tops as indicated by
the sample log and those indicated by the electric log of a well. (See
generalized graphic sections accompanying logs of selected wells in
Appendix B at the end of this report) Caving of rock material from
higher in the drill hole commonly results in fails from younger
formations being found in samples from older formations. Such
discrepancies can generally be recognized if the regional geology is
known.
Because of the factor described above and the fact that most of
the species in the faunal lists of this report were picked from unon-
trolled cuttings some of the asmblages may contain species that
have caved from sediments penetrated higher in the drill hole. How-
ever, an effort was made to eliminate from the lists all the forms that
were obviously out of place. All the species identified by Steve Her-
rick, Druid Wilson, Harbans Puri, and Ruth Todd were picked by
the author from well cuttings.
The stratigraphic terminology used in this report is that of the
Florida Geological Survey.
PREVIOUS WORK
The earliest published report touching upon the geology of
Eacambia and Santa Rosa counties was a discussion of the water sup-
ply of west-central and west Florida by Sellards and Cunter (1912).
They described the physiography, drainage, soils, and water wells of
the area The following year 11913) Matson and Sanford published a
report m the geology and ground water of the entire State and briefly
described the physigaphy. geolog). and water supply of Escambia
and Santa Rama cunties
Jacob and Cooper (1940, open file report) of the U. S. Geological
Survey made a detailed investigation of ground water in the Pensa-

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 15

cola area. Their report contained a section (eight manuscript pages)
on geology by Sidney A. Stubbs who described the physiography and
drainage of the area as well as the Pleistocene, Pliocene, and shallow-
lying portion of the Miocene deposits. Stubbs gave several detailed
measured sections of these beds and logs of seven shallow wells, two
of which were based on his examination of the samples.
Structure contour maps by Applin and Applin (1944) record the
presence of beds of Oligocene and older age beneath the western
Panhandle.
Cooke (1945) briefly described the Citronelle Formation in
Escambia and Santa Rosa counties and gave a short measured section
in the bluffs along Escambia Bay. He also mentioned the occurrence
of Pleistocene marine terraces at several places and noted how far
the Pamlico sea extended up the major rivers and bays.
Calver (1949), in a report on Florida kaolins and clays, briefly
discussed several localities in Escambia and Santa Rosa counties
where such clays are exposed.
MacNeil (1949) and Carlston (1950) described the Pleistocene
marine shore lines and terraces; both reports contained maps showing
the locations of some of these features in Escambia and Santa Rosa
counties.
Heath and Clark (1951) reported on the occurrence of ground
water on the Fair Point Peninsula in Santa Rosa County. The report
included a short but informative discussion of the geologic forma-
tions from Miocene to Recent and portrayed these units in two
geologic sections.
Puri and Vernon (1959), in a summary of the geology of Florida,
gave a generalized review of formations in the Panhandle. The report
included a chart of stratigraphic nomenclature for the Panhandle and
the peninsula, as well as a generalized subsurface geologic section for
the Panhandle that listed formations from Late Cretaceous to middle
Eocene in age. A structure map that included Escambia and Santa
Rosa counties showed contours on top of a horizon in the Eutaw
Formation of Late Cretaceous age.
The IL S. Soil Conservation Service published a comprehensive
report by Carlisle (1960) on the soils of Escambia County. The report
contains 74 pages of aerial photographs on which various soil types
were outlined in minute detail.
The first detailed geologic study of Escambia and Santa Rosa
counties was made by Marsh (1962) in connection with an investiga-

FLORIDA GBOLOLIAL SURVEY BULLTrIN NO. 46

tion of the water resources of the area by the U. S. Geological Sur-
vey. An interim report of that investigation (Musgrove, Barracough,
and Marsh, 1961) and a final report (Muagrove Barracough, and
Grantham, 1965) ummarize the geology and water resources of
Eacnbi and Santa Rosa counties.
Brracoogh and Marsh (1962) made a detailed study of aquifers
and quality of ground water along the Gulf Coast of western Florida
in Escambia, Santa Rosa, Okaloosa, and Walton counties.

ACKNOWLEDGMENTS
The cooperation and assistance of numerous geologists in provid-
ing basic data were invaluable for the successful completion of this
report. I should like to express grateful appreciation to R. O. Vernon,
Director of the Florida Geological Survey, and his associates, C. W.
Hendry, Jr. and J. W. Yon. Jr., who kindly loaned electric logs, well
sample, and other data. Vernon, Yon, and Harbas Puri reviewed
the report and made many helpful suggestions. Professor Lyman
Toumia of Florida State University gave advice on certain problem
a itrtigraphic correlation. Fossils were identified by S. M. Herrick
Ruth Todd, Druid Wilson, and Estella Leopold of the U. S. Geolgi-
cal Survey, G. A. Cooper of the U. S. National Museum, and H. S.
Puri ft the Florida Geoloical Survey. R. C. Howard and M. F. Kirby
of the Gulf Oil Corporation kindly made available wel samples and
electric lo The figure on page 76 is based on well logs supplied by
the St. Regis Paper Company through the courtesy of David Young,
Amistant Manager. The logs were prepared by the consulting firm of
lagette Bra aheas and Graham.
Especial appreciation is expressed to the geologists of The Cali-
fornia Company, Peneacola office: E. L. Russell (geologist-in-charge),
H. E. Province, W. E. Moore, and J. F. Schindler whose ever-cheer-
ful and gracious assistance in providing electric logs, references, and
other data, and helpful advice on innumerable occasions contributed
very substantially to the report. B. K. Driver, also of The California
Company, was most helpful in making well samples from the con-
pany's files available.
The Rinehart Oil News Company and Exploration Surveys, Inc.
of Dallas, Texas, supplied local and regional gravity mape and
granted permission to use data from them in the present report.
The photomicrographs were taken by Jack D. Moore, whose
skillful and painstaking work is much appreciated.

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 17

Also, I would like to thank my colleague, Jack T. Barraclough,
who made numerous valuable suggestions throughout the investiga-
tion.
The fossils mentioned in this report were identified by many per-
sons. Some are widely known professional paleontologists, others are
geologists with various degrees of competence in paleontology, rang-
ing from those who (like myself) have had little experience in fossil
identification to those who have devoted considerable time and study
to the subject. Some of these persons have identified only a few of
the fossils listed here, whereas others have identified scores of fos-
sils. In order to give due credit to various persons for their identifica-
tions, as well as to indicate the source of each identification, most of
the fossils in this report are followed by the initials of the person
who identified them, as follows:
EA Esther R. Applin, Geologist, U. S. Geological Survey,
Vicksburg, Mississippi.
RH Ralph Heath, District Geologist, Ground Water Branch,
U. S. Geological Survey, Albany, N. Y.
CH Charles W. Hendry, Jr., Assistant Director, Florida Geo-
logical Survey, Tallahassee, Florida
SH Steve M. Herrick, Geologist, Ground Water Branch, U. S.
Geological Survey, Atlanta, Ga.
OM Owen T. Marsh, Geologist, Ground Water Branch, U. S.
Geological Survey, Nashville, Tenn.
WM Winnie McGlarery, Paleontologist, formerly of the Ala-
bama Geological Survey, Tuscaloosa, Ala.
HP Harbans Purl, Paleontologist, Florida Geological Survey,
Tallahassee, Fla.
SS Sidney Stubbs, Geologist, formerly of the Florida Geologi-
cal Survey, Tallahassee, Fla.
RT Ruth Todd, Micropaleontologist, Paleontology and Strati-
graphy Branch, U. S. Geological Survey, Washington, D.C.
RV Robert O. Vernon, State Geologist and Director, Florida
Geological Survey, Tallahassee, Fla.
DW Druid Wilson, Paleontologist, Paleontology and Strati-
graphy Branch, U. S. Geological Survey, Washington, D.C.
GC G. A. Cooper, Paleontologist, U. S. National Museum,
Washington, D. C.

FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

STRATIGRAPHY
The formations underlying Escambia and Santa Rosa counties
that are considered in this report are described below, from oldest to
youngest, and include the following: Hatchetigbee Formation, Talla-
hatta Formation, Lisbon equivalent, Ocala Group, Bucatunna clay
member (Byram Formation), Chickasawhay Limestone, Tampa
Formation, Pensacola Clay (new formation), Miocene coarse plastics,
and Citronelle Formation. The section concludes with a brief discus-
sion of terrace deposits, marine terraces, and paleeoeography.

TERTIARY SYSTEM
LOWER EOCENE
WILCOX GROUP
Hatchetigbee Formation
Type locality. The Hatchetigbee Formation is the uppermost
division of the Wilcox Group. Its type locality is Hatchetigbee Bluff
on the Tombigbee River, Washington County, Ala., 3 miles south of
the Choctaw County line, where it is exposed at the crest of the
Hatchetigbee anticline. The formation was first described by E. A.
Smith (1886, p. 10), former State Geologist of Alabama. Smith
(Smith and others, 1894, p. 149-150) stated that it consisted of a
series of brown, yellowish and reddish sandy clays interbedded with
fossiliferous glauconitic marl. According to Smith, the Hatchetigbee
in Alabama is about 175 feet thick.
Distribution and thickness. The Hatchetigbee Formation
underlies westernmost Florida at depths ranging from 1,270 feet below
sea level in the northeast corner of Santa Rosa County to 2,750 feet
below sea level in southern Escambia County, shown in figures 3, 5-
10. The thickness of the formation in this area averaged 320 feet,
ranging from 220 feet in northwestern Santa Rosa County to 420 feet
just east of Pensacola.
Lithology and fossils. In the area of this report the Hatchetig.
bee Formation consists predominantly of gray to dark-gray, silty,
micaceous clay. The clay is fossiliferous and calcareous and contains
a little pyrite. Beds of gray to light-gray, hard glauconitic shale,
siltstone, and shaly limestone are present in lesser amount Fossils
include several foraminifers, such as Lepidocycina sp. and Globi-
gerina sp., corals, echinoids, shark teeth, pelecypods, and gastropods.
At the base of the Hatchetigbee Formation is the Bashi Marl
Member which is about 10 feet thick in westernmost Florida. The

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Section parallels the regional dip.

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20 FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Bashi was originally described as a separate formation (Smith and
Johnson, 1887, p. 43-47) consisting of (in descending order); (1)
Woods Bluff or Bashi fossiliferous, glauconitic marl, 15 to 30 feet
thick; (2) gray sandy clay with thin seams of lignite near the base, 25
feet thick; (3) yellowish crossbedded sands, 35 to 40 feet thick; and
(4) a lignite bed 2 feet thick. F. S. MacNeil (1947) reduced the Bashi
from a formation to the Bashi Marl Member of the Hatchetigbee
Formation for use in Alabama. Subsequently, the marl in the Hatch-
etigbee Formation was designated as its basal member and the re-
mainder of the Bashi Formation was included in the underlying
Tuscahoma Sand. Because of the thinness of the Bashi in western
Florida, it could not be recognized in well samples; in the present
report it is defined by the electric log. As such, it is a distinctive and

Iu 7 i i q r E cai R u
Li l8rals I iC S

4eol I oPPFI MIn SSEM 0s iW -C he te h h
ln._ri----rn the geBIi c on (figl__6_10).
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Figure 7. -Geolgic ctitnn C-C' acruos Escambia and Santa Rotsa counties,
Stectitin iprallels Ih regional dip.

regionally extensive marker bed which is widely used by petroleum
geologists for correlation in the Gulf Coast; hence, the Bashi is shown
(to scale) on the geologic sections (figs. 6-10).
Contacts and electric-log expression.--The Hatchetigbee rests
conformably upon the Tuscahoma Sand of early Eocene age and is un-
conformably overlain by the Tallahatta Formation of middle Eocene

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F Ht

V

i
..- A

I
, I I

--- 5_

VE lIV -
I -

-

--I

S\ \ "-:: I

* rh~

' & I L F.t
^"^*.u^t

--r

'sraEcu

cr
O*R

rC
urn
'V1

=*

z

-----4 z

I~Z

--_ z
: ---- -

= i

Figure 8. Geologic section D-D' across Escambia and Santn Roms counties.

Section parallels the regional strike.

! 1 ;

4A..L- ".

FLORIDA GIr;OLOGrAL SURVEY BULLlmN No. 46

age. Electric logs indicate that the Tallahatta becomes more clayey
or shaly toward the gulf, making it increasingly similar to the
Hatchetighee in the southern third of the area. Near the northern
border of the area an increase in the number of electrically resistant
beds, such as limestone or sand, in the upper part of the Hatchetigbee
increases its lithologic similarity to the Tallahatta. Separation of the
two formations in these parts of the area is thus somewhat arbitrary
and is based primarily on electric-log correlation with the established
section in the Pollard oil field, 2 miles north of the area. Throughout
most of Escambia and Santa Rosa counties, however, the contact
between the Hatchetigbee and the Tallahatta is sharp; the very low
resistivity of the Hatchetigbee contrasts with the intermediate re-
sistivity of the Tallahatta whose resistivity curve, reflecting the more
varied lithology, is highly irregular. The Bashi Marl Member at the
base of the Hatchetigbee can be easily recognized because its resistiv-
ity is several times greater than that of the units above and below.
MIDDLE EOCENE
('c1AIBORNE GROUP
Tallahtna Formation
Type locally. The Tailabatta Formation was named by Dall
4 1898, p. 344) from exposures in the Tallahatta Hills in north-central
Choctaw County. Alabama. The formation was previously known as
the "buhrstone" because of its many hard, siliceous beds in the west-
ern part of the state. In Alabama, the Tallahatta "consists predomi-
nantly of claystone, but its ithology is varied and includes also looe
sand, hard, quartzite, sandstone, and clay. It attains a maximum
thickness (of 130 feet) in the western part of the State and thins
eastward to a few thin ledges in the vicinity of the Chattahoochee
River in western Georgia" (Toulmin and others, 1951, p. 93).
Distribution and thickness. Beneath the western Florida Pan-
handle the Tallahatta lies at depths ranging from 1,040 feet below sea
level in the northeast corner of Escambia County to 2,530 feet below
sea level in southern Escambia County (gs. 5-10), Its minimum
thickness of 170 feet is at Pensacola, and its maximum thickness of
310 feet is near Chumuckla Springs in northwestern Santa Rosa
County. The average thickness of the Tallahatta where it is pene-
trated by oil test wells in the area is 255 feet. The formation is thus
considerably thicker in the subsurface of western Florida than in the
outcrop measured by Toulmin and others (1951, p. 94), in Choctaw
County. Aabama. At Pollard, Alaama, the formation is approxi-
mately 240 feet thick Winter, 1954, p. 127, fig. 3).

%
't t E 0

*E -ti E W I

_ f 1. E a '' i

*nr *',V aw er (t i,

1-------- Ch
DCL 4L rROuP

I L 0I4BO EIIuivALf 'Y

O

Figure 9- Geologic section E-E wrros Escambia and Santa Rosa counties.
Section parallel the regional strike.

FLORIDA GEOLOGICAL SURVEY -BULLETIN No. 46

Lithology and fossils.- In Escambia and Santa Rosa counties
the Tallahatta consists predominantly of hard, light-gray, calcareous
shale and siltstone with numerous interbeds of gray limestone and
very fine to very coarse, pebbly sand. Some of the shale is sparsely
carbonaceous. A little gray or brown clay is also present. Pyrite was
noted in a few samples. Fossils include a few gastropods and sporad-
ically abundant foraminifers among which the following were noted:
Lepidocyclina (Polylepidina) antillea Cushman
Lepidocyclina (Lepidocyclina) pustulosa H. Douvill6
Pseudophragmina sp.
Robulus sp.
In addition, a single tiny cup coral was found.
Contacts and electric-log expression. -The Tallahatta Forma-
tion unconformably overlies the Hatchetigbee Formation and is dis-
conformably overlain by the Lisbon equivalent. The very irregular
character of its resistivity curve on electric logs indicates that the
Tallahatta is made up of a series of different rock types alternating
in relatively thin beds. The intermediate resistivity values (1 to 6
ohm-meters) of the Tallahatta contrast with the low resistivity of the
Hatchetigbee below and the high resistivity of the Lisbon equivalent
above. The average resistivity of the Tallahatta tends to decrease
somewhat down-dip.
Equivalent of the Lisbon Formation
Type locality and regional variations. The type locality of the
Lisbon Formation is at Lisbon Landing on the Alabama River, Clarke
County, Alabama. According to Smith (1886, p. 130-131), the type
section at Lisbon Bluff consists of about 53 feet of fossiliferous sandy
clays and glauconitic sands. Cooke (Adams and others, 1926, p. 272)
gives a section of the Lisbon at High Bluff on the Choctawhatchee
River in eastern Alabama, totaling 172 feet of sand, clay, and marl-
stone. Toulmin (1951, p. 102) reports that in Choctaw County, Ala-
bama, the Lisbon consists of "about 200 feet of very fine-to coarse-
grained glauconitic fossiliferous greensand beds with indurated calcar-
eous layers, beds of very fine light-tan and brown sandy clay, medium-
fine to coarse sand, argillaceous sandstone, marl, and clay." Toulmin
(1951, p, 109-110) gives a section of the Lisbon in southern Choctaw
County that includes two beds of limestone. Winter (1954, p. 127)
indicates that at the Pollard oil field in southern Escambia County,
Alabama, the Lisbon consists predominantly of shaly limestone with
some shale and has a thickness of about 500 feet Puri and Vernon

0

C4 i
Ii "
a a

O ------ 0.i a

E t

Figurr 10- Geoloic wftkion F-r Rerun Ewambia armd Santa It.Ro. cujng.e
Mhowng Iformations along the rorthw border of the am&.
Figure4 to-Coop atonFPame santaadSat oe onis
showin formtio aln h otenbre fd ra

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

(1959, p. 42) make the following statement in regard to the Lisbon
Formation of the Florida Panhandle:
"The plastic beds stratigraphically equivalent of the Avon
Park limestone of the Florida Peninsula are recognized in the pan-
handle as the Lisbon Formation. These sediments are composed of
cream colored, glauconitic, sandy limestone; light gray, blocky
clay; cream, soft, chalky, pyritic limestone; and light gray, calcar-
eous glauconitic sand. ... The thickness of these clastics vary
from 300 to 425 feet."
It is therefore apparent that the Lisbon equivalent of the Florida
Panhandle, as well as of southern Escambia County, Alabama, is
very different both in lithology and thickness from the type Lisbon.
Despite the presence of Lisbon fossils, additional study may show that
the calcareous interval in the Panhandle should be given a new forma-
tion name in recognition of its lithologic difference from the type
Lisbon. However, the proper introduction of a new name for this unit
would require a more intensive and regional study, both of the type
Lisbon and of what has been called Lisbon in the Panhandle, than
was possible in the present investigation. Because the interval in ques-
tion is referred to as Lisbon by petroleum geologists as well as the
Florida Geological Survey and to avoid the premature introduction of
a new formation name, the shaly limestone between the Tallahatta
Formation and the Ocala Group in the western Panhandle is desig-
nated in this report as the Lisbon equivalent.
Distribution and thickness. The Lisbon equivalent underlies
Escambia and Santa Rosa counties, Florida, at depths ranging from
510 feet below sea level in the northeast corner of the area to 2,090
feet in the southwest corner of the area (figs. 5-10). The formation
averages 495 feet in thickness, ranging from 345 feet in northern
Escambia County to 600 feet in east-central Santa Rosa County.
Lithology. Between its type locality in southwestern Alabama
and the area of this report the Lisbon equivalent undergoes consider-
able thickening and faces change. Gulfward the sands and clays of the
type Lisbon give way to predominantly calcareous deposits. In the
western Florida Panhandle, the Lisbon equivalent consists chiefly
of shaly limestone whose color ranges from dark gray to brownish gray
to very light grayish cream. The rock is more massive and compact
than the overlying Ocala Group and breaks into hard blocky frag-
ments speckled with glauconite.
The Lisbon equivalent contains a number of shale zones, two of
which are especially prominent (p. 57). The upper zone is present

26

GEOLOGY or ESCAMIA AND SANTA ROSA COUNTIES FLOwA 27

throughout the area except in the southern part Its top lies generally
from 120 to 170 feet below the top of the Lisbon equivalent. This zone
is quite variable: at some places it consists of from one to four thin
beds occupying an interval of 10 to 80 feet; elsewhere only a single
bed, locally as thick as 70 feet, is present The lower shale zone is
present only in the southern part of the area where it occur close
to the base of the formation. It consists of a single bed of shale 60 to
90 feet thick. The material making up these shaly zones ranges from
a silty shale to a shaly siltatone. It is generally hard, light grayish tan
to light gray, calcareous, and glauconitic.
The Lisbon equivalent also contains some gray clay. Well samples
from the formation commonly contain a little very fine to very coarse,
pebbly sand; but it is difficult to determine how much of this is
actually derived from the Lisbon equivalent and how much repre-
sents cavings from sandy formations higher in the drill hole.
In northeastern and east-central Santa Rosa County and southern
Escambia County, a concentration of glauconite and/or phosphate
occurs at the base of the Lisbon equivalent. Sixty percent of a
sample from a well in southern Escambia County consisted of dark-
green glauconite grains In well W-3179, northeastern Santa Rosa
County, glauconite pellets and grains make up from 5 to 15 percent
of the samples in the lowermost 270 feet of the formation. Pyrite also
occurs in this zone at many places. Some replacement of bell and
wood fragments by both of these minerals has occurred. In well
W-3317, about 5 miles to the northeast, samples from the lowermost
150 feet of the formation consist of from 5 to 20 per cent green glau-
conite and black phosphate grains. Some of the black grains were
tested with ammonium molybdate and gave a positive reaction indi-
cative of phosphate. Apparently there is a close chemical relationship
between the glauconite and the phosphate, for several transitional
pellets were noted, half a pellet consisting of shiny, black, waxy-look-
ing phosphate; the other half of dark-green glauconite. This concen-
tration of glauconite is evidently widespread, although sporadic in
occurrence, for Toulmin (1951, p. 102) reports that in Choctaw
County, Alabama, "the basal part of the Lisbon ... is especially rich
in glauconite."
Fossils. Foraminifera are abundant in many parts of the Lisbon
equivalent The species tabulated below (Table 1) were identified by
S. M. Herrick in assemblages from oil-test-well samples from Es-
cambia, Santa Rosa, and Okaloosa counties. For locations of the
wells, see Appendix A at the end of this report Some of the species

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Table 1. Foraminifera found in the Lisbon equivalent in
Rosa, and Okaloosa counties. Florida.

Escambia. Santa

s Le Wall Depth
(eetO

Asteriprtin lia nouaks CaI n and u Todd
Calotabulimln esimi (RuihakI
Clilcide papmreudozerimn Usbomnrwlas Ban
ClaVUiR hbramlettel ? Cusbmin
Cyclammina Zp4
Dentllima jdauanansm l (Cuahman and Appiln)
Globigerin ap.
LepldocycUm (Polylepldina) anUllU Cauman
Lepldocyctlna (Piloleptdlu)] ulmr Cole and Poton
MargknultmS IrgrLa (GiBmbel) var,
MargbUlima ct. Mt owel Garrett and Klls
Marglnuna vacavll et i (Bannan
odosarka latzjugata carolmtean Cuhman
Nodarkma ,f N. vertetrall (Blatlch
Nusmmutles flortdehs Hellprtn
Nummuila gravellW (Cole)
Nummulista marlawamnoe [Vaughanm)
Nummulltea sahblme.rl (Cole)
Nummulitea mtrlatoretlculatu (L Rutten)
Nuummulite trinilaleaI l (Nuttall)
Pweudianouarila oain (Bundy)
Peudo hragini (Proporoccltrn) htnl Cole
Robulus alato-rr mbtnh (t mb*I)
Eobuluw arcutoetriatu cmrolianlan Cuabmma
RobF u inonatus (d'OrtCipy)
Ibuims pe.rdowi rt Cote
SaMrcenari arcuAt (fOrbigny)
sIplh ta claibornesia Cushma
Srvltes sp.
Sprroplec-am alKnn mBilealJiplert (Cl uhman)
Uvtutrina sup.

W- 2225

W- 3225
W-5M52
W-3455
W-3179
W-3179
W-3225
W-3455
W-5179
W- 3379
W-3455
W-4348
W-3179

W-3179
Welt X
W-4150

W-41SO
W-8179
W-3179

W-31T7
W-317B
W-3455
W-3119
w-3225
W-3225

listed were found at more than one depth, or in more than one well.
In this and other faunal tables in this report, only the shallowest
occurrence is noted.

Other fossils in the Lisbon equivalent of westernmost Florida
include: Lepidocyclina (Lepidocyclina) pustulosa H. Douville and
Discocyclina sp. (HP): two ostracods, Cytheridea moodyi (author?)
and Cytheridea wallacei (author?) (SH), Vermicularia sp. (a bur-
rowing snail ranging from Carboniferous to Recent but abundant in
the Tertiary) (SH); the small echinoid Fibularia vaughani (Twit-
chell) (OM); bryozoans; shark teeth; and a coiled annelid tube

28

4

IB1O-120

189-1B20
1890-1920
1340-1350
1100-1130
1340-1370
180. 1920
1340-1350
1100-1130
203-2060
150-1380
l S-l1620
1100-1130
3010-3100
1260-1290
1530-1540
1260- 1290
1040.1 070
1040-1070
2180-2200
121B0 290

1040-1070
13BO 1290
130- 1370
1100-3130
1100-113
1530-1540
3040-1070
1390-1930

G EOGY oF ESCAMBA AND SANTA Rosa COUNw s, FLORIDA

(which is found in the middle Eocene of Texas), Tubulostium lep-
tostoma (Gabb) (DW). This last fossil is shown on plate 3, figure 2.
A small brachiopod, Terebratulina sp., was found in the Lisbon
equivalent and is illustrated in plate 1, figure 3.
Contacts and electric-log expression. The contact between the
Lisbon equivalent and the underlying Tallahatta is disconformable
in southwestern Alabama according to Ivey (1957) and Toulmin
(1951, p. 96). In southwestern Alabama, the Lisbon equivalent is
overlain (in ascending order) by the Gosport Sand, the Moodys
Branch Formation (limestone and marl) and the Yazoo Clay. Accord-
ing to Toulmin (1951, p. 120) east of the Tombigbee River the Yazoo
Clay gives way to the Ocala Limestone. Cagle and Floyd (1957, p.
12, table 1) report 60 feet of Yazoo Clay underlain by 40 feet of
Moodys Branch Formation in Escambia County, Alabama, just north
of the area of this report. However, in Escambia and Santa Rosa coun-
ties, Florida, no evidence was found of either the Gosport Sand, the
Moodys Branch Formation, or the Yazoo Clay. If the absence of
some or all of these beds is the result of subaerial erosion, the contact
between the Ocala Group and the Lisbon equivalent in Escambia and
Santa Rosa counties, Florida, is unconformable.
On electric logs the Lisbon equivalent shows up as a unit of high
resistivity (generally 10 to 30 ohm-meters) in contrast to the medium
resistivity of the Tallahatta (generally 1 to 6 ohm-meters).

UPPER EOCENE
JACKSON STAGE
Ocala Group
Type locality and discussion of nomenclature. Dal (1892, p.
103-104) gave the name Ocala Limestone to the limestone beds ex-
posed near Ocala in Marion County, Florida. He introduced the term
in the following statement.
"Nummuliic beds, Ocala limestone (Olgocene of Heilprin). -
Among the rocks which until recently were not discriminated from
the Orbitoides limestone, and which appear in central Florida di-
rectly and conformably to overlie the latter ... is a yellowish friable
rock containing many foraminifera, conspicuous among which
are two species of Nummutites, N. willcoxii and N. floridana HP.
... It is best displayed at Ocala, Fla., where it forms the country
rock, and has been quarried to a depth of 20 feet without coming
to the bottom of the beds."
Applin and Applin (1944, p. 1683) subdivided the Ocala Limestone

29

FLORIDA GEOLOGICAL SURVEY BULLETIN N. 46

Plate I

FOSSILS FROM THE LISBON EQUIVALENT, CHICKASAWHAY
LIMESTONE, AND MIOCENE COARSE PLASTICS

Figure 1. Marginopora verebralis Blainville? (a foraminifer) Chickasawhay
limestone, X27. (RT)
Figures 2A and 2B. Rangia (Miorang(a) microjohnsoni Gardner, Miocene
coarse lastics, X9. (DW)
2A. Exterior of left valve.
2B. Interior of left valve.
Figure 3. Terebratulina sp- (a brachiopod), Lisbon equivalent, X27. (GC)

GwOLOGY OF ESCAMBIA AND SANTA ROA COUNTIEs. FLORIDA 31

Plaf t. Foails fmnn the Liisbon equivalent Chick&awhay 1im.m and
Miocene Cam daclnti

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Figure 1.
Figure 2.
Figure 3.

Figure 4.
Figure 15
Figure S.

Figure.
Figure &
Figure 9.

Plate 2

MOLLUSKS FROM THE TAMPA FORMATION AND
MIOCENE COARSE CLASTCS
(IDENTIFIED BY D. WILSON)

Riawz phgona Gardner. Tampa Fonation. X27.
Ringifula boyntoni Gardner, Miocni e are clastics, X27.
RiHsoa n. ap. ? (related to R. phagon Gardner). Tampa Forma-
tion. X27.
Concelloria bifoliata Aldrich, Tamlp Formation. X6.
Crucibulam constrictum (Conrad). Miocene cone dasticm X6.
if.ia n a p. ? (According to Druid Wilon. this specimen "appears
to be relted to oe of the Alun Bluff speciE."), Miocene coran
cdltias (?). Xa
It:ifa dystakta Gardner. Mic nw cow r~ clatic. X9-
Twrigrida wsbgrundsierM Dal Tampa Fornation. Xi
Urit. hrris4 (Manry). Micrem coare dctic, X9.

(:EOLaX;Y OP ESCAMBIA AND SANTA RoeA COUNTIES, FLORIDA 33
Plate 2 Mollusk from the Tampa Formtimon and Miocene oanre carti.

FLmIDA GOLOmclAL SUIVY BULLETIN No. 46

Plate 3

FOSSILS FROM THE LISBON EQUIVALENT. TAMPA FORMATION,
PENSACOLA CLAY, AND MIOCENE COARSE CLASTICS
(IDENTIFIED BY DRUID WILSON. EXCEPT FIG. 3)

Fiure 1.
Figure 2
Figure 3.
Figure 4.
Figure 5-
Fiturrw 6.-

Phaccides (Bellucina) tuomnyi Dall, Miocene coarse dlatics, X6.
Tubulostium leptotoma (Oabb), Lison equivalent, X6.
Cyepromda pyrenoides Gardner. P+namo Clay. X27, (OM).
Sukaruar proa meta Gardner. Mioctne coaue cIMtics. X27.
Ohla ory zoides Gardner, Tampa Formtion X9.
"SULrakri" fAip4Man Dal. Tampa Formtion ?). X27.

34

GEor.O OF ESCA AaA AND SANTA ROSA COUNTIES FLORDA 35

Plate 3. Fomsil from the Lsbon equivalent. Tampn Formation Penaola
Clay. and Moene coarse dc-tic

FLOWRDA GeoLOGicAL SURVEY BULLTINr No. 46

Plate 4

FORAMINIFERA FROM LOWER MEMBER OF THE
PENSACOLA CLAY
IDENTIFIED BY S. HERRICK)

Figure 1- lUVrrina d. ., pigmore dTrhbiny. X30.
Figure 2. Buhlminro grmwrii Cuash XSO.
Figure 3 Bolhiio t mia uataftat Cud smn, XSO.
Figures 4A and 4R Sipha gnrrima lamvlata Cnsma X30.
4A. Side view
4B Side view
Figures 5A and 5R VdaJivdi"i o toriadno C 5A Ventral view
sB Doral view
Figure A and 6BE Cbhicmd fiandons (Cushman). X30M
6A. Ventral viw
6B Doral view
Figures TA and 7R Diaworbs p., X65.
7 Drsal view
7B Ventral view
Figure Cibicide concentricM Cu IC~ an), X65.
Figure 9. Globootnia (?) Sp.. X50.

GEOAGY or E sCAMBUA AND SANTA RosA COUNTmiS, FLORIDA 37

Plate 4. Forminifra from lower member of the Pencol Clay

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.

Plate 5

FORAMINIFERA FROM LOWER MEMBER OF THE
PENSACOLA CLAY
(ALL IDENTIFIED BY S. HERRICK)

Textularia cf. T. tatumi Cushman and Ellisor, X65.
Textulariella barretti Jones and Parker, X80.
Textularia gramen d'Orbigny, X50.
Plectofrondicularia ap., X12.
Plectofrondicularia floridana Cushman, X50.
Nodosaria raphanistrum (Linne). X65.
Nodosaria raphanistrum caribbeana Hedberg, X65.
Nodosaria vertebralis (Batsch). X65.

GEOLOGY OF ESCAMBIA AND SANTA RosA COUNTIES, FLORIDA 39

Plate 5. Foramifnimf from lower member of the Pensola Clay.

FLoRalA GOLOGICAL SuxEY BULLETIN NO. 46

into an upper member (the typical Ocala Limestone that underlies
nearly all of Florida) and a lower member. Vemon (1951, p. 111)
referred the lower member to the Moodys Branch Formation of Mis-
sissippi on a faunal basis and subdivided the Moodya Branch into the
Inglis Member below nd the Wiliston Member above Puri (1953b,
p. 130) renamed Vemon's Ocala Limestone (restricted) as the
Crystal River Formation and elevated the Inglis and Williston Mem-
bers to formations. Purl (1957, p. 24) collectively termed the Crystal
River, Williston, and Inglis as the Ocala Group and designated as a
cotype locality for the group the Zuber pit of the Cummer Lime and
Manufacturing Company in sec. 11, T. 14 S., R. 21 E., Marion County,
where 70 feet of limestone is exposed The Ocala Group and its sub-
divisions described by Puri (1953) have been adopted by the
Florida Geologica Survey, but not by the U. S. Geological Survey.
The U. S. Geological Survey recognizes only the Ocala Limestone,
the term including all Eocene limestone in Florida above the Inglis.
In this report the term Ocala Group will be used in accordance with
the terminology of the Florida Geological Survey. Thirty-three sets
of well samples from the western Panhandle were studied, but the
litbologic similarity of the Crystal River and Williston Formations in
that part of the State made it impossible to separate the two units.
Puri (1957, p. 38) states that "the Williston Formation thickens at
the expense of the Inglis Formation in the Florida Panhandle, where
Inglis is absent."
Distribution and ThicFkess. According to Cooke (1945, p. 55-
57), 'The Ocala limestone ... underlies all of Florida ..." and "ex-
tends westward nearly across Alabama to Tombigbee River, where it
merges into the Yazoo clay in Clarke and Choctaw Counties."
The Ocala Group underlies the western Florida Panhandle at
depths ranging from 290 feet below sea level in the northeast corer
of Santa Rosa County to 1,940 feet below sea level at the southern
end of Escambia County, as seen in figure 11. The Ocala has an aver-
age thickness in the two counties of about 165 feet, ranging from 90
feet just east of Pensacola to 235 feet in northeastern Santa Ros
County. To the west of the area, the Ocala thins to 50 feet or less in
southeastern Baldwin County, Alabama. For comparison, Puri (1957,
p. 37-38) reports that the Crystal River Formation is as much as 310
feet thick at the center of the peninsula and over 300 feet thick in
Jackson County in the north-central part of the Panhandle. His plate
1 (op. cit.) shows a maximum thickness of 692 feet for the Ocala
Group in Gadsden County, in the north-central Panhandle.

40

GELOGYv OP EscAMBIA AND SANTA ROmA COUNTIES, FLORIDA

1 t I S I L-rl

Figure, I. Contours on top of the Ocaa Group in the western part of the
Florida Panhandle

Lithology. At the type locality the Ocala Group consists of a
cramm to white, pa, p porous, soft to firmly cemented limestone con-
taiing large foraminifers, moflusks, bryomnans, corals, and other fos-
sils In western st Florida, the Ocalm is typical a light-gray or
gryisth-am limestone near the upper contact, channg downward
to chalky white limeitone. Locally, all limestone in te Ocala may
be white. In many wells, the fossils in the uppermost part of the
Ocal are poorly preserved. This may be due to subaerial weathering
of the uppermost beds before deposition of the overlying Bucatunna
Clay Member, for the two units are separated by a pronounced uncon-

FLoatDA GeLoG cAL Suavxy BULLETIN No. 46

formity. As at the type locality, the Ocala Group in the western
Panhandle onsist mostly of large foraminifes and other foaidl
Commonly the limestone is owm wbat lauconitic, with local replace-
meat of foils by glaonite in a few places. At some localities as
much as 5 peernt of one samples consisted of shiny brownish-gold
runded pellet that may be phsph ate. A smal amount of light-gray
clay was noted in ome samples Rock cutting of Ocala m a water
well in northern Santa Rosa County contained a few fragments of
foil wood.
Fosil and age. In northeatern Santa Roa County, a bed of
tiny echinoids, Fibularia vughani (Twitchel) (SH, HP), occur at
the bae of the Ocala and can be traced for 13.5 miles along section
B-B' (fig. 6). Although the sampling intervals were too large to per-
mit determination of the thickness of this bed, the echinoids were
found abundantly through an interval of 20 to 30 feet in some wells.
The Ocala Group of the western Panhandle contains a prolific
foraminiferal fauna of the late Eocene age. The following species,
Table 2, were picked by the writer from cuttings from wells in Escam-
bia and Santa Rosa counties and from a well (W-3225) near Deatin
in southern Okaloosa County. The identifications were made by S. M.
Herrick.
Other fossils identified in wel cuttings from the Ocala Group of
westernmost Florida include two small brachiopods, Terebratuina
sp. and Argyrotheca sp. ? (identified by G. A. Cooper), the scaphopod
Dentalium sp., and an ostracod, Cushmanidea? gunteri (HP). In ad-
dition, a variety of other animal groups are represented by remains of
corals, echinoids, bryozoans, shark teeth, fish vertebrae, sponge
spiculs, and worm tubes.
Contacts and electriclog expression. The Ocala Group overtime
the Lisbon equivalent of middle Eocene age and is ovrlain probably
unconformably, by the Bucatunna Clay Member of the Byram Forma-
tion which is middle Oligocene in age. Cooke (1945, p. 56) states that
"the top of the Ocala limestone was . a land surface before any
younger marine deposits were laid down upon it" During this period
of suberial erosion, the following beds (if present) were removed by
erosion from above the Ocala in westernmot Florida: All power
Otigocene beds, the Marianna Limestone, and the Glendon Limestoe
Member and the unnamed marl member of the Byram Formation.
The Marianna and Byram are middle Oligocene in age. A similar
hiatus exists in Madison County, in the northwest corner of the
peninsula where, according to Cooke (1945, p. 56), "the Marianna is

42

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 43

Table 2. Foraminifera found in the Ocala Group in Escambia, Santa Rosa,
and Okaloosa counties. Florida.

Spec *es

WeU

Amphistekgna sp.
Amphlrtegina chipoalnsis Cuuhman and Ptonon
Amphlutg tna leisaonL (d'Orbigny)
Amphletotvgk pinarenmst Cuhrman and Bermude
ANwmaluna blatelrals Cushman
Anmomin tlena (Cushman and Applin)
Archalmaa p-
A -ru Im-
AslrabcyrUa b ia auEMls Calo
Bob mn ackuom-eams stnMruel CutMma Lad App"li
Clbica'dns p.
CtMracids coemmu (CWaer and
Ctbirwm be*k,ub tIPzEwrr abd .obl
DvmsrlUa Ptjra mmdis (Cs-., ad AppLaB:

Diwort Iondam a Cmhmas
Elphmadum ip.
Epoades Mckuonenas (Cushman and Appli
Globelrtma Ap.
CGabortauiL menardii (d"d'rbtMny
GldaUm gibba d'Orbigny
GulttilA probl.ma d'OrbLgny
GyroLdlr tduanti d'Orbigny var.
lD bu vllI byramEnsis turgida Cumhman
Lephdocycllna (Eulepidlna) clhperi LmumaIne and Dauuvtll
Lapidocycllia (LepidocycUlna montomerrleanns Cole
Lapido-yclina ocalaa Cvubman
Marginulnla ttrap a txaaneia {(CulmaJ and Applin
Nodo s rLa Sp.
No6d0aria Ilicolaute (Gutmil
KNodeats taLjari aa anli nm Cutmaan
Sadmanat d N. rajiistn(a (LamP
Nadaurm wrtebralts (BatciW

Numaasrat tn ridrak .elpram

W-3221
W-3455
W-322
W-3256
W-3179
W-3225
W-3265
W- 345$
W. sas
W- M5
W- 3225

W-3212
W.322Sl
W- Ms
w- 3- 5
W-IM5

W-3=25
w-M5
W-90D

W-3221
W-290D
W-2978
W-3225
W-3225
W-3225
W-1076
W-3225
W-4244
W-3m
W-2m$

W- 3225
w-,1n

Durh
19"Uf

710- 750
840- 850
720- 750
1410- 440
680- 730
ala- 840
140- 1500
850- 840
BIG. w40

910- 40

goD. 610
810- a40

1470-1500
1410-1440
840- 870
450- em
8 10- M40
73D- 750
610- am
840- 070
600- 610
650- 600
780- 8M0
810- 840
750- D80
650- 00
710'- 700

72O- 750
1020- 1050
630- 010
765- m3

B51- 84O
710- 73

3 New ocurtwrr repartrted an artcet by S M. Her ck fi1'., p 23lr

FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

Species

Nummulftte marine is (Vauganm)
Nummalltn strbiatraticulautu (L Rutn I
NunmuULe trinWt ae ls (NuttI U
Nummultt willamt H rlprin
Orbullna univlern d'Orbilny
Pamdaphragmlna (Proporocyclina) IllanaIl (Cushman)
QutnueloculcU la evkpt d'Ortlpy
Rdbulus aatoimbmtu (Giumbell
Hobulusi memrlca v (Cushman)
Robrlus maerLeLnus splnouu (CuhuhmaW)
Rlobulus artuaosLtrltus (Hantlenl
Robulus arc tostriatus carolinLanus Cushman
Robulua dumbleu WetIerl and Appln
Raoblus gutticlstatun (Olimbel)
Robulus gtttlcostalu cocouonami (CUIhmanI
Robu lu Utmbosus hockyeinstn (CushmaL and Applia)
Sphaeroagpena globula (Reuse)
Spiroplectammina mlasissipplensla (Cushmmn)
Textularia c. T hannal Davis
Uvigerina cokel Cushmt
Uvigerint C. U, dumblei Cushman and Applin
UvLgerina glabrnu Cushmin
Uvigerina jacksonensis CusuHan
Valvulneria Cf. V, taxana Cabhman and ElLisor

ell Depth
wel1(it*0~

W-3225
W-3225

W-3125
W-3225
W-3225
W-3325
W-2900
W-3225
W-3325
W-3225
W-278S
W-3225
W-3455
W-3907
W-3225

W-3225
W- 3225
W-2975
W-3225
W-3789
W.3I79

W-3225
W-4357

also absent and the Ocala apparently is overlain directly by the
Byram limestone (i.e., the Glendon Limestone Member of the Byram
Formation)."

The Ocala is represented on electric logs by a high-resistivity
curve (typically 20-50 ohm-meters) similar to that of the Lisbon
equivalent although of somewhat greater resistivity. An indentation
of relatively lower resistivity in the curve generally marks the base of
the Ocala. The upper contact of the Ocala is sharply defined on elec-
tric logs and is marked by a very abrupt decrease in resistivity in the
interval of the Bucatunna Clay Member (Byram Formation) which
overlies the Ocala.

44

750- 780
810- 540
720- 750
750- 780
640- 070
780- 810
650- iB*
610- 840
720- 750
840- 870
650- M0
810. 840
1290-1300
650- 0W0
840- 870
B10- 840
810- 840
81- 840
550- no
810- 640
S80- 710
1470-1500
810- 840
750- 815

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA

MIDDLE OLIGOCENE
VICKSBURG GROUP
Bucalunna Clay Member of the Byram Formation
Type locality and history of nomenclature. The Bucatunna
Clay Member was originally described as the basal formation of the
Catahoula Group (Miocene age) and was named for exposures of
crossbedded sands, clays, bentonitic clays, and bentonite along
Bucatunna Creek in Wayne County, Mississippi. (Blanpied and
others, 1934, p. 3, 4, 12-16, etc.). Cooke (1935, p. 1162-1172) placed
the Bucatunna in the Byram Marl, a formation in the Vicksburg
Group of middle Oligocene age. Several years later MacNeil (1944,
p. 1329) changed the name Byram Marl to Byram Formation
within which he recognized three members: the Glendon Limestone
Member at the base, an unnamed marl member in the middle (the
original Byram Marl), and the Bucatunna Clay Member at the top.
Marsh (1960 and 1962) extended the Bucatunna Clay Member into
the western Florida Panhandle and showed that it pinched out east-
ward in Walton County.
Distribution and thickness. The Bucatunna extends eastward
from its type locality in Mississippi across southwestern Alabama
into Florida where it underlies the entire western Panhandle. East-
ward the Bucatunna thins, finally pinching out beneath Choctawhat-
chee Bay about 8 miles east of the Okaloosa-Walton County line. In
Escambia and Santa Rosa counties, the Bucatunna occurs at depths
below sea level ranging from about 200 feet in northeastern Santa
Rosa County to about 1,760 feet in southern Escambia County (figs.
5-10).The upper surface of the Bucatunna dips about 30 feet per mile
toward the southeast. The Bucatunna averages 125 feet in thickness
over the two-county area, ranging from about 45 feet in northeastern
Santa Rosa County to 215 feet in southwestern Santa Rosa County,
just north of Escambia Bay, shown in figure 12. The Bucatunna gen-
erally thickens toward the Gulf of Mexico.
Lithology At its type locality in Wayne County, Mississippi,
the Bucatunna Clay Member is described by MacNeil (1944, p. 132)
as consisting of fossiliferouss, calcareous clay, dark lignitic clay, lami-
nated fine sand and clay, laminated argillaceous fine sand with some
beds of coarser sand, bentonite, and here and there a bed or streak of
very fossiliferous marl at the top. ... the Bucatunna clay is commonly
fossiliferous only at the top, and in many places is barren except for
specks of lignite." In western Florida, the Bucatunna Clay Member
fits this description except for the absence of bentonite and fossili-

45

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Figure 12.- Isopfachoun map of the Bucatunna Clay Member of the Byram
Formation in Ecambia and Santa Roma counties. Florida

ferous marl; also, although samples of the Bucatunna contained from
5 to 40 per cent fine, quartz sand, this elastic material in all proba-
bility does not occur as discrete interbeds but is disseminated through-
out the clay as a gritty admixture. Sand beds such as those reported
by MacNeil (op. cit) at the type locality would be clearly discernible
on the electric logs, but all electric logs from the area show only
homogeneous clay throughout The single exception is a small but
regionally persistent "kick" of higher resistivity (up to about 5 ohm-
meters), probably representing a thin bed of limestone, that occus
generally near the base of the Bucatunna. Most well samples of the

GEOWLOY OF ESCAMBIA AND SANTA Rosa COUNTIES, FWRIDA 47

Bucatunna from Escambia and Santa Rosa counties consist of dark-
gray, soft, calcareous, silty to sandy clay which contains occasional
lecks of carbonized wood and a little pyrite. An X-ray analysis of the
clay made by H. G. Goodell of Florida State University showed that
it consisted of a "poorly crystalline illite" (J. W. Yon, Jr., written
communication. Sept 17, 1959).

Fossils and age. Although fossils are scarce in the Bucatunna
Clay Member, Foraminifera are found sparsely throughout Table 3

Table 3.- Foraminifera found in the Bucatunna Clay Member of the Byram
Formation, Santa Rosa County, Florida.

Depth
(fset)

Species

I Amp tLte mu up. (R
Archlna ct A- col~minbten Appn apd Jordsa (RT)
ASlrrgercna d. A- brmenam CNlmuan and Todd (iRT
Bo'rin mancaba hman I RTn
CLbmcdne ct. C nmrrruam ([Cahman) (SH)
Cifctd cf C c rantem Cu ~ ant EllUror (SI
*Csfbdd msnat4lqpinm (Cusman) 18m
Cibchtds teusadR (BE1us (ff3n
kblam mOamU (d'OrbQtgc q (I
GWxdumL gatb d'Ottagp (~ a
Guntull ri. G. prublem d'Orblpn (R"T
MIarltulIu sp (Sa 1
*Nummulliea dit ICole anm Pmoanl (HPI
Pyrgo byrameniai Cuahmn and Todd (RT)
QuinqUwlocUliAM pL (1T)
Quinquelaculina maruoel Cuhlmin and Todd (RT)
Quhllquvnlculun vkcksburgenBsl Cushman (RTI
Robun I aiitoilmbatus (GUimbi) lRT. SH]
Robulul cf. R. alaltnmbatus (GUimbIl) (RT)
Rhbulum cd. R. canvergnes BornFmami (SIH)
Robulus dr. R. imboau (ReuasI IRTI
*Robulfm vflckwblmrgw (Ciahanl (RFTI
Rubulu vcklu mrgnwsis (Cmahmanl ar- prta
ICushman) ( r
StpbarAm spL (NT
Sw.M.n. Oadrl" Cshman (WH
Sprspkctiaamiam inbiuippneatnii iCsteaM [RT. S9
Vntwrtn a narrsam d'rbgMy (Si
Uivgrrtr ct. U pgmera drktgu (SW)
LnvCrrim n-ck Uh gti CaHBn and Ellsoar (RT)

Wl_3L

W-307
W-3975

W. 3W

W. 3236
W-3z
W-3303

W-3307

W-330.3
?
W-.407

W-3071
W-33157
W-1371
W-32133
W- 3071

W-2303

W-3303
W-33OT
w-waw
W-33D3
W.3ao61

W-33>
5-lw)

5-J10J

I ao- 500

50- 9B00
90-. 1010
I17U- 1100
Irm-l o

1270-1040
1270-1300

9oW 2 00
988-1010

950-1010
5G-. UT
10980-1010

1270-1300
650. 700

1270-1300
720- 730

1720- 113
90- 1010

950- 9W
1170-13D0
]5O- MO
127%-1300
1270-1300
900-IOto

lists species from Santa Rosa County, with one species
County. Those indicated by an asterisk (*) are listed

from Escambia
by Applin and

FLORIDA GWECOICAL SUuVEY BUtLLEIN No. 46

Jordan (1945, p. 130) as diagnostic of the Vicksburg (Oligocene).
Although this fauna is not suffciently diagnostic to indicate any par-
ticular part of the Oligocene, the four species marked by an asterisk
definitely establish the Bucatunna Clay Member in western Florida as
Oligocene in age. At its type locality in Wayne County, Mississippi,
the Bucatunna has been assigned to the middle Oligocene.
Contacts and electric-log expression. Because the lower two
members of the Byram Formation are missing in westernmost Flor-
ida, the Bucatunna probably rests unconformably upon the Ocala
Group of late Eocene age. It is conformably overlain by the Chickasa-
whay Limestone of late Oligocene age. In places the Bucatunna and
Chickasawhay interfinger along their contact. Such local change of
faces in places causes the thickness of the Bucatunna, which is
normally rather uniform to be quite variable. A good example of
this can be seen in section B-B' (fig. 6) where local thickening of the
Chickasawhay at the expense of the Bucatunna in northeastern Santa
Rosa County has reduced the Bucatunna to a thickness of only 45
feet, the minimum thickness for the area.
On electric logs the Bucatunna Clay Member is the most clearly
defined of the stratigraphic units discussed in this report The ex-
tremely low resistivity of the clay (generally 1-3 ohm-meters) con-
trasts sharply with the high resistivity of the limestones above and
below.
UPPER OLIGOCENE AND LOWER MIOCENE
Chickasawhay Limestone and Tampa Formation undifferentiated
Because of the lithologic similarity of the Chickasawhay Lime-
stone and Tampa Formation in western Florida and the difficulty of
locating the contact in many wells, it was not considered practical to
separate the two formations on the geologic sections, although they
are described separately below. Electric logs of some wells in the area
show the contact between the Chickasawhay and Tampa as a sharp
indentation in the resistivity curve opposite a bed of considerably
lower resistivity. This bed may be a thin stratum of clay.
The top of the Chickasawhay and Tampa undifferentiated in
westernmost Florida dips southwestward about 23 feet per mile from
160 feet below sea level in the northeast corner of Santa Rosa County
to 1,540 feet below sea level in the southwest corer of Escambia
County. The Chickasawhay and Tampa undifferentiated thickens
southward and is about 450 feet thick beneath Mobile Bay.
The chief differences noted between the Chickasawhay and Tampa

48

GEOLOGY OF ESCAMIA AND SANTA ROSA COUNTS, FLORIDA

are as follows: (1) The gray limestone of the Chickasawhay is more
dolomitic than that of the Tampa, (2) the Chickasawhay also con-
tains brownish dolomitic limestone and dolomite that is absent in the
Tampa (see well W-4597, Appendix B), (3) the Chickasawhay is
somewhat more vesicular than the Tampa, (4) the Tampa contains
much more clay, mostly as beds in its upper portion, than the Chicka-
sawhay, and (5) the Tampa locally contains bits of lignite which are
absent in the Chickasawhay. The differences between the two forma-
tions are best seen in samples from wells W-3203 and W-4091 (see
Appendices A and B) and on the electric logs of wells W-2519,
W-3364, and W-4091. These distinctions, however, could be recog-
nized in only a few wells in the two-county area not enough to en-
able the two formations to be separated over the area as a whole.
Chickasawhay Limestone
Type locality and history of nomenclature. The Chickasawhay
was named for exposures of limestone, marl, and clay along the Chicka-
sawhay River near Waynesboro, Mississippi (Guidebook for the
Eleventh Annual Field Trip of the Shreveport Geological Society,
1934, p. 7-13). The formation was divided into a Lower Chickasawhay
Member and an Upper Chickasawhay Member. These beds were
originally included in the Byram Marl by Cooke (1918, p. 196). Mac-
Neil (1944, p. 1346) renamed the upper member the Paynes Ham-
mock Sand, which is equivalent to the Tampa Formation of Miocene
age, and restricted the name Chickasawhay Limestone to the original
Lower Chickasawhay Member, which is equivalent to the upper part
of the Suwannee Limestone of Florida (late Oligocene age).
Distribution, thickness, and Uithology.- The Chickasawhay Lime-
stone underlies all of Escambia and Santa Rosa counties, thickening
gulfward from about 30 or 40 feet along the northern border of the
area to as much as 130 feet along the margin of the Gulf. The forma-
tion consists of gray to light-gray, hard, highly porous or vesicular
limestone and dolomitic limestone; interbedded with light-brown,
hard, vesicular to compact dolomitic limestone or dolomite that has a
distinctive sugary texture. Fragments of the Chickasawhay Limestone
have a knobby, rough surface that gives the impression of a micro-
coquina of obscure fossil fragments, although few can actually be dis-
tinguished as such.
Fossils and age. The following is a list of foraminifers from the
Chickasawhay Limestone of Escambia and Santa Rosa counties, with
the exception of the three species identified by R. O. Vernon which
are from well W-1018 in Okaloosa County:

49

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Lepidocyclina cf. L undosa Cushman' (RV)
Lepidocyclina (Lepidocyclina) mantelli Morton' (HP)
Lepidocyclina cf. L. canellei Lemoine and R. Douville' (RV)
Lepidocyclina (Eulepidina) undosa Cushman' (HP, SS)
Lepidocyclina cf. L. yurnagunensis Cushman (SS)
Marginopora vertebralis Blainville? (RT) pi. 1, fig. 1)
Massilina sp. (RT)
Nummulites dia (Cole and Ponton)' (HP)
Nummulites forresti (Vaughan and Cole) (SS)
Nummulites tuxpanensis (Thalmann) (SS)
Peneroplis sp. (RV)
Applin and Jordan (1945, p. 130) list Lepidocyclina manteUi Mor-
ton and Operculinoides dius [=Nummulites dia] (Cole and Ponton)
as diagnostic of Vicksburg Stage (Oligocene). Cooke (1945, p. 108)
states that "... Lepidocycna favosa Cushman and L. undosa Cush-
man ... are abundant in the Chickasawhay limestone of Mississippi
and in the Suwannee limestone in Washington County [Florida]."
Contacts and electric-log expression. The Chickasawhay Lime-
stone conformably overlies the Bucatunna Clay Member of the Byram
Formation and interfingers with it locally along the contact (fig. 6).
The Chickasawhay is disconformably overlain by the Tampa Forma-
tion in the southern part of the area and by the Miocene coarse clas-
tics in the northern part. Electric logs of the Chickasawhay Limestone
show typically high resistivity values, although the resistivities cover
a rather wide range from approximately 10 to 80 ohm-meters.
Tampa Formation
Type locality and history of nomenclature. L. C. Johnson
(1888, p. 235) was the first to use the name Tampa Formation. Dall
(1892, p. 112) included in the Tampa group ". .. the Chipola beds
S.., the Tampa beds (including the Tampa limestone) and the Alum
Bluff beds. . ." Matson and Clapp (1909, p. 84-91) restricted the
name Tampa Formation to beds near the city of Tampa. Cooke and
Mossom (1929, p. 78-93) changed the name to Tampa Limestone in
recognition of its predominantly calcareous composition. The type
locality of the formation is at Ballast Point in the vicinity of Tampa,
Hillsborough County, Florida, now largely covered by buildings and
other improvements, near Tampa Bay on the west coast of peninsular
Florida.
Vernon (1942, p. 68) pointed out that "As the formation contains
considerable amounts of... unfossiliferous clay and silt, the term
SDiagnostic species.

50

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 51

Tampa limestone is not entirely satisfactory. The writer [Vernon],
therefore, returns to the old usage of Tampa formation, but with
Mansfield's paleontologic and stratigraphic restrictions (1937)."
Puri (1953a, p. 17) abandoned the name Tampa Limestone and
established in its place the Tampa Stage, which he subdivided into
two lithofacies, a "silty and clayey" Chattahoochee faces updip and
a calcareous St. Marks facies downdip. Puri (1953a, p. 20) gives a
measured section of the Chattachoochee facies at the Jim Woodruff
Dam on the Apalachicola River. However, the predominant rock type
in this section is limestone, which might make it difficult to dis-
tinguish the Chattahoochee facies from the calcareous St. Marks
faces. On the other hand, the St. Marks facies near Tampa consists of
limestone in the lower part and greenish clay in the upper part
(Puri, 1953a, p. 21). Thus, the upper part, at least, might be difficult
to distinguish from the "silty and clayey" Chattahoochee facies. Al-
though the differences between these two faces may be sufficiently
great in some areas so that the faces can be mapped separately, the
distinction between them does not seem clear-cut enough, for the
purposes of the present report, to justify their use in Escambia and
Santa Rosa counties. Accordingly, the original term, Tampa Forma-
tion, as reinstated by Vernon (1942, p. 68), will be used here.
Distribution and thickness. The Tampa Formation is present
only in the southern part of Escambia and Santa Rosa counties, hav-
ing been removed by erosion in the northern part prior to the deposi-
tion of the Pensacola Clay and Miocene coarse clastics. The Tampa
reaches its maximum thickness in the area of 270 feet in southern
Escambia County.
Lithology. According to Cooke (1945, p. 114), "In Hillsbor-
ough, Pasco, and PineUas counties, which include the type area, the
Tampa is commonly a fairly hard, dense, light-colored to yellowish
limestone." He states (op. cit., p. 113) that "the composition of the
Tampa is much more variable than that of either the Suwannee or
the Ocala, both of which are much purer limestones." Cooke adds that
in Gadsden County the Tampa contains up to 35 percent magnesium
carbonate, which would classify it as a dolomitic limestone at that
locality, whereas at other places, it may contain hardly any mag-
nesium carbonate. The Tampa in the area of this report is an example
of the latter.
In Escambia and Santa Rosa counties, the limestone is hard,
light gray to grayish white, and although in places it contains some

FLORIDA GEOLOGIAL SURVEY BULLETIN NO. 46

magnesium carbonate, it is generally not dolomitic. Locally the lime-
stone contains bits of carbonized wood and plant remains.
The Tampa contains several beds of clay, especially in the upper
part. For example, at the north end of Perdido Bay (well W-2519) the
upper 120 feet of the Tampa Formation contains four clay beds of
the following thicknesses: 7, 7, 40, and 10 feet. In 1960, a 1,088-foot
water well was drilled at the U. S. Air Force Bomarc missile site on
Santa Rosa Island, near the Santa Rosa-Okaloosa County line. A
considerable amount of tough green and brown clay was encountered
and the well had to be screened and gravel-packed to prevent the
water from becoming turbid. Barraclough and Marsh (1962, p. 16)
believe that the decreased effective porosity of the limestone resulting
from the presence of so much clay has been an important factor in
the drastic decline of water levels, amounting to more than 125 feet
since 1936, in the Fort Walton Beach area.
An unpublished log of a water well (W-1018) on Santa Rosa Is-
land about 4 miles west of Fort Walton Beach by R. O. Vernon of
the Florida Geological Survey indicates the presence of "cream-col-
ored to gray dense limestone" with many Nummulites cf N. tamanen-
sis Vaughan and Cole at a depth of 590-610 feet. In the interval 630-
640 feet, Vernon reports the occurrence of the foraminifer Archaias
floridanus (Conrad) which is diagnostic of the Tampa Formation.
Sidney Stubbs, formerly of the Florida Geological Survey, reported,
in an unpublished log, the presence of limestone "similar in lithology
to Tampa limestone noted elsewhere" at a depth of 850-885 feet in a
water well (W-454) near Holley in southeastern Santa Rosa County.
An unpublished log of an oil test well (W-4597) near Cottage Hill in
central Escambia County by H. S. Puri of the Florida Geological
Survey (see Appendix B) indicates limestone belonging to his
"Tampa stage, Chattahoochee facies" at a depth of 1,020-1,080 feet.
This limestone contains Sorites sp.
Fossils and age. The Tampa Formation of the western Florida
Panhandle contains an abundance of poorly preserved foraminifers,
as well as mollusks, corals, and echinoids. The mollusks in Table 4
were identified by Druid Wilson. The assemblage is early Miocene in
age. The Cancellaria is from southern Escambia County, and the
remaining species are from wells in central and northern Santa Ross
County. Some of these mollusks are pictured on plates 2 and 3.
Table 5 lists species of Foraminifera identified by various persons
in cuttings from wells in Escambia, Santa Rosa, and Okaloosa coun-
ties. S. M. Herrick (written communications, Dec. 27, 1960, and Feb.

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA

Table 4. Mollusks found in the Tampa Formation
bia counties. Florida.

in Santa Rosa and Escam-

Bpecie Well Depth
(feet)

AlvetinuM p. W-3787 68- 710
Anadare (CunEarca) initiatar Dall W-3313 475- 480
Cancellaria biofollata Aldrich Well X 1320-1240
Donax trueloides Gardner W-3787 950. 980
Marginella (errata) chipolana Dall W-3313 475- 480
OUlvela oryzodes Gardner W-3213 475- 480
RIsson pltgon Gardner W-3787 680- 710
Risk s a. sp. (related Lw R. phagon Gardner i W-323 475. 480
SulCularla* chipolana Dll I W-3787 1190-1220
Turrltella subgrurdlera Dall W-3787 M85- 710

Table 5.-- Foraminifera found in the Tampa Formation in Escambia, Santa
Roia, and Okaloosa counties, Florida.

peea Wll ept

Amphiltegina chlpole'ws Cuwhmnn iad Ponton (SH, SS) W-3455 W00. 510
Amphlstegina Iloridana Cushman and Pontan (SH) W-3455 500- 510
Archaia ftorldanus (Conradl (RV W-1018 630- 640
Elphidium chlpolenais (Cushman) (aS) W-454 775
Elpbidium gunterl Cole (RV) W-2507 973-1001
Spanidea mansfleldl Cushman (RV) W-2507 973-1001
Nonkln gr~ailoapl (d'Orbigny) (RV) W-2507 973-1001
Nonlcm pizarrensla Berry (RV) W-a507 073-101
Nummultteu rcL N. tamanerLa Vaigtan aid Cole (RV) W.lO18 e5M- 610
Paeudopolymorphbna dumblea (Cushman and Applin) (RV) W-1507 973-1001
Putcolna proteus (d'Otbigny) (ESH W-451 520- 530
Qulnqueok liona d Q. lamarctlana d'Orbinpy (8H) W-345 59- B60
ftobulua amerlcma ({Cushman) (SS) W-41M 776
Soritees p. 5/ (DW, RV, BP) W-4W7 2020-3080
Textularia sp, (SS) W-4 775
Uvlgerlna cr. U. pigmea d'OrbLgny ({5) W-44 775

S/ Charactcritic and widespread.
8, 1961) states that Archaias floridanus "characterizes the Tampa at
the outcrop and is the index fossil for the Tampa limestone." He cites
W. Storrs Cole as the authority for this statement. Herrick adds that
Archaias floridanus is the only foraminiferal species that is diagnostic
of the Tampa. Cole (1945, p. 20) says that this foraminifer usually
occurs near the top of the Tampa.
Contacts and electric-log expression. The Tampa Formation
rests unconformably upon the Chickasawhay Limestone and is un-

53

FLOIDA GoLmoGicAL StUViY BuLrrm No 46

cnormbly overlain by the Pesacol Clay. The Tampa is repre-
ented n etricr lop by reistivity curves of typically high value,
although ristivies may range from approximately 10 to 80 ohm-

AMDDLE AND UPPER UMOCENE
Penmcola Clay
Type locality. The name Pensacola Clay is here proposed for a
subsurface clay formation that underlies the southern part of the
western end of the Florida Panhandle and extends westward into
Alabama. The formation takes its name from the city of Pensacola,
Florida, which lies 2 miles northeast of where the formation attains
its maximum thickness in the area, as shown in figure 13. Three oil
test wels located 22 to 24 miles west and southwest of Pensacola,
figure 14, have been selected as type wells. Lithoogic and electric
log of the Pensacola Clay and exact locations of the wells are given
in figure 14. The formation consists of three members: an upper mem-
ber composed of clay, the relatively very thin Eacambia Sand Mem-
ber (new name) in the middle, and a lower member of clay.
Distribution and thick The regional dip of the beds would
ordinarily project the formation to the surface near the northern
border of the area and alo just east of Fort Walton Bech; but dis-
continuity, owing both to facie changes and to the unconformable
overlap of the Citrnelle Formation, confin the Peacola Clay to
the subsrface, illustrated in figure 15 and figure 5.
The upper member terminates eastward by changes of fadies along
a line that extends southward from just west of Milton in Santa
Rosa County to Blackwater Bay, shown in figure 16. From there the
line continues eastward almost to the Okaloosa County line where
it bends southward again and crosses Santa Rosa Island about a mile
west of the county line. The distribution of the Escambia Sand Mem-
ber everywhere coincides with the distribution of the upper member,
for where the latter grade laterally into sand of the Miocene coarse
clastic, the Ecambia Sand Member loses its upper contact and be-
coms distiginishabe from the Miocene e ar clastics The wer
member etenads much farther eat than the upper member and ends
beneath Catawhabtce Bay in southwestern Walton County, 15
milm eat of the city of Fort Walton Bach (fig. 3). Approximately 13
to 16 miles north of Prnsacola both the upper and power member
terminate along an east-was zone of interfingering with the Miocene
coar clastics. This marginal zone of facies change continues west-

54

GEOLOGY OF ESCAMBIA AND SANTA RoSA COUNTIES, FLORIDA

* -6 4j-!jR.Lf 'rJ .m *

Figur 13. IomIr Pm4 ~ map of the Pen co (Clay in th outherm half of
Ewambia a&d Santa Rom counties. Friday.

ward into Baldwin County, Alabma. The westward or downdip ex-
tent of the Pensacola Clay is not known, but electric lop indicate that
it continues at least as far as Mobile Bay.
Although the upper surface of the Penacola Clay is irreguar
(fig. 16), it dips generally southwestward and underlie the area at
depths ranging from 135 feet below sea level 6 miles northwest of
Milton in Santa Rosa County to 1,000 feet below sea level in the
southwest corner of Escambia County. The total thickness of the
formation ranges from 380 feet in the area 4 miles northwest of

56

FLmIDA GOmwcccAL Su vaY BurLLrN NO. 46

416 OF 6d"U WqN SM.'w a **,

J--J*W s Ul ol ., .-~
$a&A --s a l |th

-- .... : ; w . -- .- ,
--* . :- -
^ * "*" ^ *.'j. ". ^ f : i w ~ c t ^ .y i ^

Fi gur 14- Elctric-log corrtrliion of the hre type wrls of the Penacola
Cay in southern Baldwin County. Alabama. showing interfinger-
ing in the upper part of the fornmtion as the amount of clay
increases gullward.

GEoMocv or Es CtalA AND SANTA ROSA CouNrtCs, FLwmID

-- i-.--
Y r~q -:z

1 E
.. .. .-.. ,, -
t> F -

,r1- SI I

"- '. .' ', .-I ,. 1 .-
I -. L ^ili .,
1 ,* f l" 9 q
_ .I d %' 'II - F'01 1

1.j 'r [m^c"r1i r
;-,.. .' I

-, r r-l""- i-

Ed 'I 1 [
.,,.,, .,

Si

'I

.q'
El

V I

., m Umfl *. I.. m

N & m. m mi m I
n-I 4'
ba~ cr 1 ~ I
a na et f
- -~ -1I a ~I~~ LY
a -- fl -

Figunr 15, Electric lo of wkrctd oil ttet wedll showing rw nation of geo-
logic formutions in muthw'etern Alabma mad the wertn Plarid.
Panhandle.

Pensacola to more than 1,000 feet at Mobile Bay. The upper member
ranges in thickness from 240 feet about 10 miles east of Pensacola to
680 feet 2 miles southwest of Pensacola. The lower member ranges in
thickness from 150 feet at the Santa Rosa-Okalooea County line on
Santa Rosa Island to 330 feet at Fort Walton Beach. The Escambia
Sand Member thickens southwestward from a minimum of 20 feet at
the Chemstrand Plant, about 6 miles north of the mouth of the
Escambia River, to a maximum of 160 feet in the area 4.5 miles west
of the mouth of the Perdido River.
Lithology. The upper and lower members of the Pensacola Clay
consist of tough, dark to light gray clay, but at a few localities it is
brownish gray. The clay is typically silty and contains variable
amounts of very fine to very coarse, quartz sand. Bits of carbonized
wood and plant remains, such as leaves and reeds, are present

i

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Fixur 16. -Contours on togp of the Pensacola Clay in the southern half of
REcarnmia and Santa Rosa counties, Florida,

throughout the formation. The clay is micaceous and slightly calca-
reous. Some pyrite is also present Locally, the formation grades into
a clayey siltstone. Mollusk shells and foraminifers are abundant
throughout the Pensacola Clay. The former are especially abundant
in the upper part of the upper member in west-central and southern
Escambia County, where thick beds consisting almost entirely of
shells are found near the top of the upper member. The relatively
high resistivity of these shell beds makes it difficult to pick the
formation top on electric logs in this part of the area.

.58

-Y

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA

The Escambia Sand Member consists predominantly of light-gray
to brownish-gray, fine to coarse quartz sand. Northwest of Pensacola
the member is made up of very coarse sand and quartz granules in
the lower part and pea-size gravel in the upper part. In southern
Santa Rosa County, the Escambia Sand Member contains some
carbonaceous material and an abundance of black grains, possibly
phosphate, in the lower 5 feet.
Sample logs of type wells. Three oil test holes in southeastern
Baldwin County, Alabama, were selected as type wells for the Pensa-
cola Clay. They are Baldwin-Garrett No. 1, Temple-Ehle No. 1, and
Temple-Sherrill No. 1. Figure 14 shows the locations of these wells
and how they are correlated by means of electric logs in the interval
of the Pensacola Clay. One set of samples for each type well is on
file at the Alabama Geological Survey in Tuscaloosa, Alabama. De-
tailed sample logs of these wells are given in Appendix B at the end of
this report. The three logs given below cover the interval of the
Pensacola Clay in these same wells, but the depths of lithologic units
have been adjusted to agree with the electric logs of the holes.
Baldwin-Garrett No. I
Depth below
Lithology land surface (feet)
Miocene coarse plastics:
Sand, fine to coarse ......................-........ ........ 620-660
Clay, gray, with Bolivina marginata multicostata
and Textularia gramen (WM) ......-...--...--... 660-720
Sand, fine to coarse ~................................ 720-760
Clay, gray ................ ........-------------........ 760-775
Sand, echinoids and foraminifers ........... ....-.. 775-825
Upper member of Pensacola Clay:
Clay, gray, pyritic; Siphogenerina lamellata,
Bolivina marginata multicostata (WM) .......... 825-840
Clay, gray; a little coarse sand; very scarce shell
fragments; foraminifers including Robulus cf.
R. vaughani and Siphogenerina lamellata
(900-930 feet) (W M ) ....................... .............. 840-970
Sand, coarse .................................... 970-980
Clay, gray; with Cibicides cf. C. floridanus
(960-990 feet) (W M ) ..................................... 980-995
Sand, coarse ............................. .............. 995-1,010
C lay, gray ............................................ ................ 1,010-1,030
Sand, coarse ......................................... 1,030-1,045

59

FFLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

Depth below
land surface (feet)

Lithogy

Clay, gray .............. -.-. ..------ .... .. . 1,045-1,085
Sand, co rse ........... ............... ....... ... 1,085-1,095
Clay, gray -......... ..... .... ......... ...... ... .... 1,095-1,105
Sand, coarse ........ . ................. ....... 1,105-1,130
Clay, gray, some coarse sand, a few shell frag-
ments; foraminifers including: Bolivina margi-
nata multicostata, Bulimini inflata, and Buli-
minella cf B. curta (1,170-1,200 feet) (WM);
Robulus americanus spinosus (1,210-1,240
feet), Robulus americanus (1,270-1,300 feet),
and Robulus vaughani (1,360-1,390 feet)
(OM) and the mollusk Phacoides choctaw-
hatcheensis (1,330-1,60 feet) (OM) .............. 1,130-1,425
Eacambia Sand Member:
Sand with thin layers or lnses of clay; a few
small mollusks; otoliths and Siphogenerina f.
S. lamellaa (WM ) .............. .............--- 1,425-1,515
Lmwer member of Penscola Clay:
Clay, gray, with a little pyrite; contains some
medium to coarse sand; a few sheD fragments
and small mollusks: foraminifers including
Boivina floridana and Cibicides ftoridans
(W M ) ....... ................. ......... ..................... 1,515-1,910
Chickasawhay Limestone and Tampa Formation undifferentiated:
Limestone, light gray, containing a few layers of
gray clay; foraminifers scarce ................ 1,910-2,200+

Temple-Ehle No. 1

Depth below
land surface (feet)

Lithology

Miocene coarse plastics:
Sand, light gray, very fine to coarse, micaceous,
abundant shells of gastropods caphopods
and pelecypods including Phacoides choctaw-
hatcheensis ............. .....- ...... . .....
Clay, light gray, shells .. .... .... ......... ... ..
Sand, light gray, coarse, abundant shells and
m uscovite. .. .. .......................... ..
Clay, gray, carbonaceous, and shells; sandy .........

470-685
685-765

765-785
785-800

60

G EOLGY OF ESCAMBIA ANo SANTA ROSA CO~ NTiES, FLRIDA

Depth below
land surface (feet)

Lithology

Sand, very light gray, coarse; abundant shells;
som e gray clay .......... ................. ................
Upper member of Pensacola Clay:
Clay, gray; very abundant shells of small pelecy-
pods and gastropods including Astarte isoso-
les. a few foraminifers including Plectofrondi-
cularia sp. and Robulus cf. R. vaughani, echi-
noid plates, bryozoans, scaphodods, fish
vertebrae, and a few tiny brachiopods ..........
Sand ......... .... ... .... ... .......
Clay, gray, abundant shells as at 850-880 ft, fora-
minfers including Amphistegina eesoni, Mas
sitina sp., and Robulus americanus spnoss ....
S an d .....................- ...-.- .. .. .......................
Clay, gray. and some coarse to very coarse sand;
abundant shells as at 850-880 ft .............
Shells of small pelecypods, including Phacoides
choctawhatcheensis, and small gastropods (es-
pecially Turritella-shaped) including Ringi-
cul boyntoni ....... .........................
Clay, gray, with shells .. ...... ....................
Shells, as above; some light gray silty clay ...........
Clay, light gray to dark gray, sandy, abundant
shells of small mollusks as above ........ .......
Escambia Sand Member of Pensacola Clay:
Sand, fine to coarse, and clay, gray to dark gray,
in alternating thin layers; abundant shels .....
Lower member of Pensacola Clay:
Clay, dark gray, with abundant shells of mollusks;
a few fish vertebrae and fragments of carbon-
ized wood; a few foraminifers including Boli-
vina floridana, Uvigerina sp., Siphogenerina
lamellata, and Nodosaria cf, N. raphanistrum ..

800-850

850880
880-895

895-940
940-960

960-1,010

1,010-1,065
1,065-1,110
1,110-1,130

1130-1,400

1,400-1,495

1,495-1,930

Tampa Formation and Chickasawhay Limestone undifferentiated:
Limestone, very light gray, vesicular, glauconitic;
foraminifers few to abundant: thin layers of
gray clay .. .. ..... ..... .... .... 1.930-2,000
Limestone. very light gray, glauconitic ....... .. 2.000-2,055

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Temple-Sherrill No. 1

Lithology lan
Miocene coarse plastics:
Sand, coarse to very coarse ..............................
C lay, gray ....... ... ..... ........... ...... ..................
Sand, gray, very coarse to granules; abundant
sh ells ........... .. .. ..... ...... ............................
Upper member of Pensacola Clay:
Clay, gray; abundant shells of small pelecypods
including Rangia (Miorangia) microjohnsoni
(WM, OM), a few gastropods, and a few fora-
minifers including Amphistegina lessonii
(W M ) .................. .............. .......... ....... ... ........ .....
Sand, gray, very coarse to granules, some fossils
as at 730-745 feet ........................ ....................
Clay, gray; some fossils as above ----------...........
Sand, coarse to very coarse, abundant shells in-
cluding Rangia (Miorangia) microjohnsoni
(OM) and Chione sp. (WM) ---- ..-----
Clay, gray; abundant mollusk shells ..............
Sand, gray, very coarse; abundant shells ..............
Clay, gray, abundant shells ................................
Sand, gray, very coarse; abundant mollusks ........
Clay, gray, silty; abundant shells; some sand .......
Escambia Sand Member of Pensacola Clay:
Sand, gray, medium to very coarse; abundant
sh ells ................ ........ .... ....... ..
Lower member of Pensacola Clay:
Clay, gray, carbonaceous, rather pure, slightly cal-
careous, pyritic; shell fragments very scarce;
a few foraminifers including Bolivina flori-
dana and Uvigerina sp. (WM) ...-...........
Sand, coarse to very coarse, pebbly; 5 percent
shell fragm ents ............. ...................................
Clay, gray, slightly carbonaceous and calcareous;
shells scarce ... ................... -- ..-
Sand, medium to very coarse; shell fragments
fairly common; very few foraminifers; one
small land (?) animal tooth..... .. .

Depth below
i surface (feet)

520-620
620-635

635-730

730-745

745-765
765-780

780-825
825-835
835-845
845-860
860-985
985-1,215

1,220-1,305

1,305-1,500

1,500-1,570

1,570-1,650

1,650-1,670

62

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 63

Depth below
Lithology land surface( feet)
Clay, gray, slightly calcareous and carbonaceous;
shells very scarce; abundant foraminifers of
Miocene age including species of Robulus,
Uvigerina, and Globigerina __........ .......... 1,670-1,725
Tampa Formation and Chickasawhay Limestone undifferentiated:
Limestone, light to dark gray, glauconitic; some
clay, probably present as thin layers: echinoid
spines and foraminifers, scarce to fairly com-
m on ........................................ .......... ....... ..... 1,725-1,900
Fossils and age. The Pensacola Clay contains a prolific fora.
miniferal fauna and an assemblage of small mollusks. The fossils in-
dicate an age of late middle to early late Miocene. Table 6 shows the
biostratigraphic distribution of Foraminifera that were found in the
lower member of the Pensacola Clay, seen on plates 4 and 5. The
biostratigraphic subdivision of the Miocene used in this and subse-
quent tables and in the discussion in the text follows the usage of the
Florida Geological Survey and differs in some respects from the usage
of the U. S. Geological Survey. The forms identified by S. M. Herrick
are from oil test well W-3225 near Destin in southern Okaloosa
County, about 19 miles east of the Santa Rosa County line. Species
identified by Sidney Stubbs are from water well W-454 in southeast-
ern Santa Rosa County. The three species identified by Winnie Mc-
Glamery are from an oil test well in southeastern Baldwin County,
Alabama.
Other species of Foraminifers that were found in cuttings from
the lower member of the Pensacola Clay (well W-3225 in southern
Okaloosa County), which do not appear on Puri's distribution charts
(1953a), are listed in Table 7. S. M. Herrick made the identifications.
The snail Vermicularia sp. was also found in the lower member of
the Pensacola Clay near Destin in southern Okaloosa County. In
southeastern Baldwin County, Alabama. two crab claws and a tooth
were found in the Pensacola Clay.
The age of the lower member, based on its microfauna, is late
middle to early late Miocene.
Tables 8 and 9 show the biostratigraphic distribution of Fora-
minifera that were found in well samples from the Escambia Sand
Member and the upper member of the Pensacola Clay.
Siphogenerina lamellata is an index to the Arca zone of the Choc-

64 FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

Table 6.- Biostratigraphic distribution (according to Purl, 1953a) of Foramini-
fera found in the lower member of the Pensacola Clay in Escambia,
Santa Rosa. and Okaloosa counties, Florida. (Age indicated by as-
semblage: late middle to early late Miocene)
-pper Middle
Miocene Mocene
Choctaw- Aum
hatchee Bluff
_StM stAge

So*S
Fotambitera ad

uSFi IS ( feet)

Bolivin flaridana Cushnmn (WM, S31 X X W- 454 875
Bolivina marginata multtcOtata Cushman (IB, sS) X X W-3225 270- 300
Bulimin graciiU Cushman (SH) X W-3225 270- 300
Butlmina tnflata Perner (aS) XX W- 454 675
Cibcides conentricus (Cushman) (SHI X X X X W-3225 270- 300
Cibcldes floridanus (CuasmMn) (WM, SH) X X X X W-32i5 270- 300
Discorbis florldana Cushman (SH) X W-3225 270. 300
Eponides mansfleldl Cushman (SS)} X X W- 454 675
Eponldes repandus (Fichtel and Moll) (SH) X W-3235 300- 330
Globorotlia ci, G- menardii (d'Orbigny) (SH) X X X W-3225 300- 330
Nonion pizarrensis Berry (SH) X X W-322S 270- 300
Orbutina nmiversa d'Orbigny (I1H) X X X W-3225 270- 300
Plectaorondicularia floridana Cushman (SH) X W-3225 300- 330
Robglui amoricanui (Cushman) (SH, SS) X X X W-3225 270- 300
Robulus americanus spinanus (Cusahmin) (SH, SS) X X W.3225 270. 300
SRoblus vaughati (Cushman) (SH, BS) X X X W-3225 270- 300
Sigmaillna tenuis (Czjzek) (81H X X W-3225 300- 330
Siphogenerma lamellata Cushman (WRM, SH) X W-3225 270- 300
Siphonlna jackeonensis ar- 1Umbasus Cushman (SB) X W- 454 675
Tnatularia gramen d'Orbigny (SH) X X X W-3225 300. 330
Textulartela barretti Jones and Parker (SH) XK W-3225 270- 300
Uvigerlna peregrina Cushman (RV) X XX W-3507 X71- 032
ValVu.inerta flridana Cushman (SH) X X XX X X W-3225 20- 300
Virgulina fusiformks Cushman (SS) XX W- 454 700

tawhatchee (Puri, 1953a, p. 50). S. M. Herrick (written communi-
cation, Dec. 27, 1960) makes the following statement on Foraminifera
from the western Florida Panhandle: "... no Foraminifera geologi-
cally older than the middle Miocene were observed on any of the
slides. One exception in this connection might be Robulus vaughani
which Cushman reports as lower Miocene in age. As this fossil occurs
along with a micro-fauna that is not older than upper-middle to mid-
dle Miocene, it would seem that extension of the stratigraphic range

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 65

Table 7. Additional species of Fnraminifera from the lower member of the
Pensacola Clay, fund in cuttings from well W-3225. southern
Okaloosa County.

Species Depth

DOtcorbiB c., D. subaraucnal Cushman 270- 300
ClobigerLna op. 270- 300
Nodwaria raphanistrum (Linn) 270- $00
NodosarLa raphaniatrum caribbean. Hedberp 300- 330
Nodosaria vertebralis (Batsch) 300- 330
Planularia sp. 270- 300
Plectolrondicularia vaughan Cushman 270- 300
Trxtularia of. T, talumi Cushman and ELLsor 300. 330
Uvkge-irU pigmea d'Orblgny 270- 300

Table 8.- Biostratigraphic distribution (according to Puri, 1953a) of Fora-
minifera found in 1he Escambia Sand Member of the Pensacola
Clay in Santa Rosa County. Florida, and Baldwin County, Alabama.
[Age indicated by assemblage: late middle to early late Miocene]

Upper Middle
Miocene Miocene
Chbocaw- Alum
hatchee Bluff

Foraminifera

Il a 31.o -

____l *! ( fee
=j -2 -a
F >39 B Well CpRl

Ampbiategina cI. A. loridana
Cuahman md Panton (RU) X X W-2297 775- 795
Robujlu amertcaau (Cushman) (WM) X X X IBldwin- 1270-1300
Garrett
No. 1
Robulus naughani (Cushman) (SS) IX X I X W- 454 500
Stphogenerir lameilaLa Cusltman (SS) 'X W. 454 500
Triloculina ci. T. oblanga
C(oftagu) (RR) X W-2207 775- 795

of this species might be in order." E. R. Applin (written communica-
tion to Herman Gunter, Florida Geological Survey, June 15, 1940)
gave a log of samples from the stratigraphic level of the upper mem-
ber in water well W-223 at Warrington, southern Escambia County,
and makes the following notation in the summary:

66 FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

"MIOCENE
326-390 Choctawhatchee Brownish gray clays
carrying a micro-fauna which is Choctawhatchee
in age."
The ostracod Haplocytheridea bassleri Stephenson was found in
the upper clay member in central Escambia County by H. S. Pun
(unpublished log of well W-4597) According to Puri (1953a, p. 48),
"Haplocytheridea bassleri, which is very abundant in the Shoal River

Table 9. Biostratigraphic distribution (according to Puri, 1953a) of Fora-
minifera found in the upper member of the Pensacola Clay in
BEcambia and Santa Rosa counties, Florida, and Baldwin County.
Alabama,
Upper Middle
Miocene Miocene
Choctaw- Alum
hatchee Bluff
stage Stag

Faraminifera sF g >

L) Well

BoUvlna marginal Cuehman (SS) I x x 454 475
Bolivina mrginata muUL.cotatat Cushman X X Baldkwl- 820- 850
W m)Garrett
M, H No 1
Bumina graclUs Cushman (5) | X W- 454 325
BuUln tJ flata Perner (WM) X X Baldwin- 1170-1200
Garrett
No. 1
Bullminella cf. B. curta Cushman (WMi X 2K IBadwin- 1170-1200
Garrett
I No. 1
Buliminella elepnntussima (d'Ortlgny) (EA) X, XX X W- 223 340- 390
Cthicldes concentricu (Cushman) (EA. RH) X X K X W- 323 325- 340
Cibiclden ci- C. Cloridanus (Cushman) (WM) X XX XX Baldwin- 960- 990
i l Garrett
No- 1
Elphidilm rimbrlatulum (Cuehn n) (8) K X X X W- 454 425
Etpldltum poeyanum (d'Orlgny] (EA) X X X W- 223 32S- 340
Globorolalia menardU (d'Orblgny) (l B X X W- 454 325
Gypelna veakeularis (Parker and Jones) (8) X W- 454 325
Monlon grateloupi (d'Orbl y) (88) X X X X W- 454 325
Nonian plarrensis Berry (EA, SBB X X W- 223 325- 340
Plecrorndrkcularia rmanLeldI Cushnmn x W- 464 450
and Pont a ) I
Pyruina albatrosl Cumahn mad Osm w (BA) X W- 223 325
Qulnqueloculkn cf. Q. cantarta d'Orbigny (RH) X W-22l 320- 343

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 67

Upper MWdle
Mwncene MiPcne
I Chctaw- -I- A Am
batchee BlufI
1tage Stage

Foram Lni era I

SU 1 % Depth

Robulus L merlcanum (Cunkman) (81, OM) X X X W- 454 400
RPbulu amuricanus spinnaus (Cushmtanl (RH, S) XX W- 454 275
Robulue lotus (Cushman) (S3, RH XXXX W- 54 400
Robulus vaughan2 (Cushmn) (WM, RH) X K: X W-2297 762- 775
SigmamDrphina pearcuyl Culhman and Oz~wa (S ) XI X W- 454 450
Slpbogenerina lamelatal Cushman (WM, RH. 85 ) W- 454 375
Textularia agghitln;ita d'Orbigny (EA) X X W- 223 325- 340
Textulara gramen d'Orbigny (EA K K X W. 22.3 a5- 340

facies, is a brackish-water form .. and it dominates the modern bay
microfauna." The upper member contains numerous mollusks, among
which are Barbatia propatula busana Harris and Phacoides crenulatus
Conrad var., both reported by R. O. Vernon in cuttings from well
W-2516 in the interval 442-489 feet, and Cypraeolina pyrenoides
Gardner (OM), found in well W-4091 in the interval 560 to 620 feet.
Correlation. The Pensacola Clay cannot be traced into any
established formation, either to the west, to the north, or to the east.
South of the area it extends for an unknown distance beneath the
Gulf of Mexico. For this reason, the unit was given a new name, the
Pensacola Clay. In central Escambia and Santa Rosa counties and
also about 28 miles east of the area the Pensacola Clay grades later-
ally into the Miocene coarse clastics. The Pensacola Clay is considered
equivalent, at least in part, to the Hattiesburg Clay and Pascagoula
Clay of Mississippi and the Choctawhatchee Stage (Arca, Cancellaria,
Yoldia, and Ecphora faces) and the Alum Bluff Stage (Shoal River,
Oak Grove, Chipola, and Hawthorn faces) of Florida.
Contacts. In the southwestern part of the area, and possibly
also in the southeastern part, the contact between the Pensacola Clay
and the underlying Tampa Formation is gradational and probably
conformable. Because of the alternation of clay and limestone beds
near the contact, the division between the two formations is neces-
sarily somewhat arbitrary in this part of the area. The contact is
placed at the top of the uppermost limestone bed. In the central and
northern parts of the area the contact is nongradational and uncon-

68 FLRnIDA GEOLOGICAL SuRVEY BULLETIN No. 46

formable, for northward the Chickasawhay-Tamipa beds have been
increasingly beveled by subaerial erosion prior to deposition of the
Pensacola Clay. This has resulted in a stratigraphic hiatus that in-
creases northward, involving first t(he complete removal of the Tampa
Formation, then removal of the upper part of the Chickasawhay
Limestone.
In most of the area, the Pensacola Clay is overlain conformably
by Miocene coarse plastics. In south-central Escanbia County and
southwestern Santa Rosa County, however, the Pensacola Clay is
unconformably overlain by the Citronelle Formation whose flatter-
lying basal beds gently truncate the uppermost strata of the Pensa-
cola Clay. East of Fort Walton Beach, where the upper member is
absent, the Citronelle Formation unconformably overlies the lower
member of the Pensacola Clay.
In the southwestern part of the area (downdip), the upper contact
of the formation is difficult to pick because of the interfingering of
sand and clay beds. Figure 14 shows the nature of the upper contact
of the Pensacola Clay, which is arbitrarily placed at a depth of 805
feet below sea level in well 334 and at 785 feet below sea level in well
651. The contact in well 832 is sharp and not arbitrary; it is found
at a depth of 905 feet below sea level. The upper member thickens
considerably toward the Gulf as more and more landward-pointing
tongues of clay enter the section. These tongues of clay presumably
join a thick, continuous body of clay beneath the Gulf of Mexico
beyond where the seaward-pointing tongues of sand pinch out. Con-
versely, in a landward direction, the upper member becomes increas-
ingly thinner as more and more tongues of clay pinch out and are re-
placed by sand. This landward increase in sand in the section is also
apparent in the lower member, for the northernmost of the three wells
in figure 14 (well 832) penetrates two seaward-pointing tongues of
sand, the upper one 70 feet thick, the lower one 20 feet thick.
Electric-log expression. The Pensacola Clay is represented on
electric logs by a curve of very low resistivity, generally 1 or 2 ohm-
meters. Shell beds near the top of the formation and sand beds, such
as the Escambia Sand Member, are indicated by somewhat higher
resistivities in the range of 3 to 9 ohm-meters.
Mliouren Coarse Clastics
In the southern part of the area the Pensacola Clay is overlain
by a coarse-clastic deposit composed of sand with some gravel and
clay. In the northern part of the area, beyond the limits of the Pensa-
cola Clay, this coarse-clastic unit is considerably thicker than in the

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 69

southern part. The lower portion of this thicker section interfingers
laterally with the Pensacola Clay to the south (fig. 5). A similar
faces change also occurs along the eastern margin of the Pensacola
Clay. The coarse plastics of the western Panhandle cannot be definite-
ly correlated on a lithologic basis with any of the established Mio-
cene formations in the state. The Florida Geological Survey is cur-
rently making a study of unnamed coarse-clastic deposits of various
ages and uncertain correlation throughout the state for the purpose
of clarifying their stratigraphy and ultimately to provide suitable
names for them. This study includes a drilling program to obtain sub-
surface information, as well as an examination of surface outcrops. In
the present report the unnamed coarse plastics in the western Pan-
handle will be referred to informally as the Miocene coarse plastics,
pending the assignment of a formal name.
Distribution and thickness. The Miocene coarse plastics are
present everywhere in the western Panhandle except in an area be-
tween central Escambia County and southwestern Santa Rosa Coun-
ty, where the Citronelle Formation lies unconformably upon the
upper member of the Pensacola Clay, and in the area east of Fort
Walton Beach, where the Citronelle lies unconformably upon the lower
member of the Pensacola Clay. The thickness of the Miocene coarse
plastics is variable, generally ranging from about 70 feet in north-
central Escambia County to as much as 500 feet in west-central
Santa Rosa County. (See fence diagram, fig. 5).
Lithology. Except for the fossils, the Miocene coarse plastics
are virtually indistinguishable from the overlying Citronelle Forma-
tion. However, the almost total absence of fossils in the Citronelle and
their abundance in the Miocene coarse plastics provides a striking
lithologic contrast that makes separation of the two units a relatively
simple matter. Thus, the separation is based on shells as a purely
lithologic aspect of the sediments without regard to the geologic age
indicated by the various fossil species. Most of the wells in the area
first penetrate several hundred feet of sand, gravel, and clay of the
Citronelle in which scarcely a single fossil fragment is found. Just
below the base of the Citronelle, however, there is an abrupt appear-
ance of shells (mostly tiny gastropods and pelecypods) in considerable
abundance.
The Miocene coarse clastics consist chiefly of light-brown to light-
gray, poorly sorted fine to very coarse sand and granules and small
pebbles of quartz. Muscovite is abundant throughout. At several
places in both the northern and southern parts of the area the sand

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

contains abundant fragments of carbonized wood. This material is
especially abundant in well W-2862, west-central Escambia County,
at a depth of 670-700 feet; an estimated 10 percent of the sample
from this interval consists of black lignite. Light to dark-gray, car-
bonaceous clay and siltstone that are somewhat calcareous occur
throughout the unit as lenses up to 180 feet thick. In northeastern
Santa Rosa County, about 60 feet of pea-size gravel is present near
the top of the coarse plastics. Locally, a few black phosphatic pebbles,
fragments of limonite, and pieces of hardpan (sand cemented with
iron oxides) were noted.
The most distinctive feature of the Miocene coarse plastics is the
numerous shell beds that occur throughout. These beds consist mostly
of minute mollusks that commonly make up 5 to 50 percent of some
well samples. In a well just north of Pensacola, in southern Escambia
County, the upper three-quarters of the Miocene coarse elastics con-
tains so many shell beds that half of the rock material from this
interval (300 feet in thickness) consists of shells.
Fossils and age. In the southern half of Escambia and Santa
Rosa counties, where the Miocene coarse elastics overlie the Pensacola
Clay, the coarse elastic unit is of late Miocene age. Beyond the limits
of the Pensacola Clay to the north and east, the lower part of the
coarse clastics unit is the same age as the Pensacola Clay -late mid-
dle to early late Miocene and the upper part is late Miocene. Here
the Miocene coarse plastics are equivalent, or at least in part, to
both the Alum Bluff and the Choctawhatchee. This age assignment
is based on the foraminiferal and molluscan fauna described below.
Table 10 gives the biostratigraphic distribution of Foraminifera
picked from well samples of the Miocene coarse plastics.
Three diagnostic species of ostracods were identified by Harbans
Puri in samples of the coarse plastics from a depth of 390 to 400 feet
in oil test hole W-4991 (fig. 4);
Cytheretta burnsi (Ulrich and Bassler) upper Miocene
Cytherideis ashermani (Ulrich and Bassler) upper and
middle
Murrayina gunteri (Howe and Chambers) Miocene
Other species of Foraminifera that were found in the Miocene
coarse plastics include the following:
Anomalina cf. A. basiloba (Cushman) (RH)
Archaias sp. (SH)
GIobigerinoides trilobus (Reuss) (RH)

GEOLoGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 71

Plectofrondicularia sp. (OM)
Siphogenerina cf. S. advena Cushman (RH)
Sorites sp. (SH)

Table 10.- Biostratigraphic distribution (according to Purl, 1953a) of Fora-
nminifera found in the Miocene coarse plastics in Escambia and
Santa Rosa counties. Florida, and Baldwin County, Alabama.
(Age indicated by assemblage: middle and late Miocene)

ppWr Middle
MIocene Mtooene
Chocuw- Al
latchbe Bluff

Sta oa

AmphiLstega lesonll (d'Orbipy) (WW XX X Temple- 120- 780
SherrUi
to. 1
Bovina marginata mulucatata CLuhmtma (WM) X X Baldwin- 2L0- 7Wl
Grrrett
No. 1
Cibleldem cf. C. onceuntricus (Cushmnm) (RI) X X X X W-2297 907- 31
NMon grntliupvt ({dOrbigny) XX X X W-a297 27- 321
SQuInqueloculina cotatat d'Orbigny (SH) X X X W-4 10 80- 6M0
SQunqualoculina c Q. anmarekiaas d'Orbty (RHR x K x W-a97 04- 212
Quinqulocuuina semnulum (IUnB) 8IH, HE) X X W-297 204- 212
Robulua amerinuua (Cushnuwa (lRH) X X X W-2397 297- 321
Robulum americamnu splnoMlu (Custman) (RHO X X W-2297 273- 27
Romblus atLus(Cushman) (tIR X X X Kx W-2297 27r- 297
Robulutm c. vaughani (Cushman) IRM X X W-2297 373- 297
Teatulatri gramen d'Orbigny ({W) X X X Baldwi- 630- 70
Garett

Table 11 contains a composite list of molluscan species that were
found at various places within the coarse-clastics unit in Escambia
and Santa Rosa counties. It is not intended to represent an assem-
blage of species that would be found together at a single horizon. The
mollusks listed in the table ranged from middle to late Miocene in
age. All were identified by Druid Wilson. Mansfield (1932, p. 13)
listed Phacoides choatawhatcheensis as a characteristic species of his
Area rubisiniana zone. Earlier, Mansfield (Cooke and Mossom, 1929,
p. 140-142) had designated this zone as the type zone for the Choc-
tawhatchee Formation. Because the Choctawhatchee Formation was

FLORIDA GEOLOGICAL SURVEY- BULLETIN NO. 46

Table 11.- Composite list of mollusks found in the Miocene coarse classics
in Escambia and Santa Rosa counties, Florida.

pecs we Deph
Spectes Well (feet)

Anchl n- p. 7? W-3056 100. 1O0
Astarte (Bythiamena) Ioscele Gartdner W-2978 340- 30
CmnrelarU bhtfolUam Aldrich Well X 1220-1140
Phaeoldes (Bellucina) tuomeyl Dall (pl. 3, fig. 1) W-3055 B0- B0
Phtcoldes (Pleuraluctna) choctawhatchleent Mu utleld W-3203 300- 410
RuingL (Morangta) micro)ohnsoni Gardner W-304B 60- 70
Ringicuit boyMta Gardner W- 500 720
Sulcularia proacucata Gardner (pL 3. fig 4) W-3203 380- 410
Turritella alctda Dal1 W-978 340- 300
Turritella ubgrundultelera tll W-4901 360-
Uzita dytakta Gardner Well X 460- 480
Ulitas utyktl Gardner W-2w08 I 340 300
Uzita harrisi (Maur) W-5009 420
VenerlfArdLa (GIyptrmtis) up. W-4 257 30- 300

not a true formation, being defined primarily on the basis of fossils,
Puri (1953a, p. 28) changed it to the Choctawhatchee Stage.
According to Druid Wilson (written communication, Dec. 9,
1963), "Rangia (Miorangia) microjohnsoni Gardner... has never
been reported from either the Alum Bluff or the Choctawhatchee, but
is a characteristic mollusk in some facies in the Mississippi embay-
ment and has always been considered late Miocene." Puri (1953a, p.
56, 57) states that the Pascagoula of middle and late Miocene age is
characterized in the central and western Gulf States by a single fauni-
zone, the Rangia johnsoni-Miorangia microjohnsoni faunizone, and
that Miorangia microjohnsoni is the subsurface equivalent of Rangia
johnsoni. This fossil is illustrated in plate 1, figure 2.
The two small gastropods, Ringicula boyntoni Gardner and Uzita
harrisi (Maury) (illustrated on plate 2), which hitherto have been
reported only from the Chipola Formation, were identified by Druid
Wilson in samples of the coarse-clastics unit from a well in southwest-
ern Escambia County, north of Perdido Bay. In this well, these fos-
sils occur in the Miocene coarse plastics, which overlie the Pensacola
Clay. As the upper part of the Pensacola Clay is late Miocene in age,
it appears that the range of these two species should be extended.
Other fossils found in the Miocene coarse clastics include a few
tiny brachiopods in southeastern Baldwin County, Alabama, and some
teeth identified by Frank Whitmore (Druid Wilson, written com-
munication, Nov. 14, 1960) as those of a small mammal, from north-

72

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 73

ern Santa Rosa County. A few fish vertebrae, bryozoans, echinoid
plates, and a barnacle were also noted.
Contacts and electric-log expression. The Miocene coarse
plastics rest conformably upon the Pensacola Clay in the southern
half of the area and unconformably upon the Chickasawhay-Tampa
in the northern half. The Miocene coarse clastics are overlain un-
conformably by the Citronelle Formation everywhere in the western
Panhandle. The unconformity, seen in figure 17, is marked by an

-u-I
9W - I .Re*de 5&'q
-e -M E-m W w
LZ -,Ew -en 0 aw'ta rmh d
'AWWO P ftON In V
M -
t. U to

FigurnL 17. Cntours on top of the Mincene section in westernmost Florida.
This is a surface o(f unconformity underlain chiefly by upper
Miocene coarse plastic sediments.

FLORIDA GEOLOGICAL SURVEY -BULLETIN No, 46

uneven surface formed by subaerial erosion before deposition of
the fluvial(?) sediments of the Citronelle. Pirkle (1960, p. 1392-
1393) reports that "shell beds of late Miocene age have been en-
countered beneath the Citronelle sediments in a number of locali-
ties" in Polk and Lake counties. He concludes that "the occurrence
of Citronelle sediments of similar lithology overlying Hawthorn
materials of highly contrasting types [early and middle Miocene
age] suggests the presence of an unconformity at the base of the
Citronelle beds." Pirkle supports this conclusion by citing the
presence of rubble and old soil zones, solution surfaces, and con-
centrations of phosphatic pebbles along the contact. Cooke (1945,
p. 191) gives a measured section of Alum Bluff in Liberty County
(central Panhandle) in which he shows the Citronelle Formation
resting unconformably upon the Duplin Marl of late Miocene age.
The Miocene coarse plastics are represented on electric logs
by curves of high resistivity ranging from 15 to as much as 250 ohm-
meters. Numerous beds of clay throughout the coarse clastics are
indicated by sharply lowered resistivities, generally in the range
3 to 8 ohm-meters.

QUATERNARY(?) SYSTEM
PLEISTOCENE(?) SERIES
Citronelle Formation
Type locality. The Citronelle Formation was named by Mat-
son (1916, p. 168) for exposures at the town of Citronelle in north-
ern Mobile County, Alabama, and especially northward along the
Mobile and Ohio Railroad for a distance of 3 to 4 miles. At the type
locality the formation consists predominantly of light-yellowish
brown to reddish-brown, very fine to very coarse, pebbly sand with
some white clay as thin layers and pellets scattered throughout.
Only the lower part of the formation is present at the type locality,
the upper part having been removed by erosion.
Distribution. The Citronelle extends eastward and south-
eastward from the type locality into Florida where it underlies all
of Escambia and Santa Rosa counties and continues eastward across
the Panhandle for an undetermined distance. How much of the
virtually unfossiliferous sand-gravel-clay sequence that is found in
the rest of the State should be included in the Citronelle is yet to
be resolved. Puri and Vernon (1959, p. 128) included the "un-
named coarse plastics" of the eastern Panhandle in the Hawthorn
Formation of early and middle Miocene age. Cooke (1945, p. 230)

GEOLoG oF EsCAMBIA AND SANrA ROSA COUNTIES, FLOJIDA 75

and Pirkle (1960, p. 1383-1385) correlate the kaolinitic sands ex-
posed in the central ridge of the peninsula with the Citronelle.
Thickness. The thicknesses given here for the Citronelle
Formation in Escambia and Santa Rosa counties include the Pleis-
tocene terrace deposits because, as Carlston (1950, p. 1120) points
out, "it is virtually impossible to differentiate Pleistocene sand and
gravel of the marine terraces from the Citronelle sand and gravel."
However, the terrace deposits are probably relatively thin, and
therefore, their inclusion would not greatly alter the general thick-
ness figures. Together the Citronelle and the terrace deposits range
in thickness from about 30 feet at the southern border of Santa
Rosa County to about 790 feet in northwestern Escambia County.
The combined thickness of these two units in Escambia and Santa
Rosa counties is quite variable for two reasons: (1) The base of
the Citronelle appears to be an irregular surface of unconformity,
and (2) the top of the terrace deposits coincides with an irregular
topography of considerable relief.
Carlston (1950, p. 1120) remarks that "the Citronelle forma-
tion ... ranges from 40 to 130 feet thick in coastal Alabama, be-
cause of pre-Citronelle relief and a general thickening toward the
Gulf." Matson (1915. p. 178) says that the formation may be more
than 250 feet thick in southern Alabama and that west of Mobile
it may have a maximum thickness of 340 feet. Cooke (1945, p. 230)
believes that "in Florida the thickness is probably of the same order
of magnitude" as that given by Matson. The results of the present
study do not appear to agree with the thickness figures of either
Carlston or Matson, although those obtained for Escambia and
Santa Rosa counties are closer to Matson's figures. Despite the
gulfward thickening of the Citronelle in coastal Alabama reported
by Carlston, just west of the area of this report the Citronelle
apparently thins southward (toward the Gulf) as well as eastward
in Escambia and Santa Rosa counties, Fla.
Lithology. In Escambia and Santa Rosa counties, the Citro-
nelle consists principally of quartz sand which contains numerous
lenses, beds, and stringers of clay and gravel. The lithology changes
abruptly over short distances, as shown in figure 18. The sand is
typically light yellowish brown to reddish brown, although some is
white or light gray. The grains are mostly angular to subangular
and very poorly sorted, ranging from very fine to very coarse. Musco-
vite is abundant throughout. In places the sand grades into gravel
composed of quartz and chert pebbles up to an inch in diameter. A

FLoarDA Gw=LOicGAL SuVEY BULLETIN No. 46

A
SasM

oow

_ .-. -

a\ IP 1
>nV

'' /
w*t- r& A- ^

i^r^
t : m

P -
67n

Sawa

5fE:r'.: ._*;-t r. r.;" '-I..- j _t.S1:- ,
-"3'qr:.Z "--1 ;'., :, "' ut r a,-

Figure 18. Facies chanrC in the upper part of the Citronlwtl Formation in
west-cenlral Eiambia County. Florida. showing extreme varia.
biliav of lithology over short distance.

few pebbles of silicified oolitic limestone were noted in samples from
the northern part of the area. Elsewhere the sand grades into siltstone
and clay. The siltstone is light gray to light yellow and in places con-
lains abundant carbonized plant remains. The clay occurs in lenses
as much as 60 feet thick and is chiefly white or gray, although some is
lavender, yellow or brown. Fragments of carbonized wood are common
in the gray clay. At Molino in Escambia County. clay for making
bricks is mined from a lens that is 50 feet thick. Although it is diffi-
cult to ascertain the horizontal extent of the clay beds within the
Citronelle, they probably range from a few feet to 2 or 3 miles in
length (fig. 18).
A distinctive rock type that occurs in the Citronelle Forma-
tion throughout western Florida and southern Alabama is a limon-
ite-cemented sandstone called "hardpan," shown in figure 19. This
rock, formed by cementation of sand with iron oxides probably precipi-

76

B

a I

801

ZOW

GEOLOGY OF ESCAMIBIA AND SANTA RosA COUNTIES, FLORIDA

ra a

Figurn' 1a. b. -

Layers o himorntune-cementid sandstone ('hardpan) in sand
of the ('wLrnrlle Firmnation on the wr't .ide of Perdido Ray
Baklwin County, Alabama. 1 mile waulhwest of the Lillian
Bridge and 12 milr wntet of PensaroLia FlHrlLa The irnm-oxid.
ceamnting malrlrial wa- probably prciiqtatAd from grouwl
water. Ph ptiiuranphs by T0 Marsh.

-.F -Ar :

FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

Figure 19c. Peculiar tubular structures in "'hardpan", forming a boxwork of
extremely hard sandstone cemented by limonite. These structures
are exposed in the Citronelle Formation in a roadcut along U. S.
Highway 29 just southwest of Brewton in Escambia County,
Alabama, 6% miles north of Santa Rosa County, Florida, Photo-
graphs by O. T. Marsh.

tated from ground water, is dark rusty brown and is generally
extremely hard, although some may be rather soft The "hardpan"
most commonly occurs as layers that parallel the bedding of the
enclosing sediments. These layers range from a fraction of an inch
to 3 or 4 feet in thickness. In places, the "hardpan" is filled with
peculiar curving tubular structures of uncertain origin, from a frac-
tion of an inch to several inches in diameter, shown in figure 19c.
These tubular structures parallel the bedding and are filled with the
same loose sand that encloses the "hardpan" layers. Little is known
concerning the lateral extent of these hardpan layers, but it is unlikely
that any given layer extends for more than a few thousand yards.
Escambia and Santa Rosa counties are dotted with hundreds of ponds,
many of which probably owe their existence to "hardpan" layers at
or near the surface.
Detailed section of the upper part of the Citronelle Formation in
the cliffs along the west side of Escambia Bay, about 11 miles
north of East Pensacola Heights, Escambia County; 4 mile

GEoLOcy oF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 79

south of line between T. I S. and T. 2 S. in R. 29 W., Pensacola,
Fla., quadrangle. This is one of the largest and best outcrops
in Florida. The section is representative of the sediments ex-
posed all along these bluffs.
Thickness
Unit (Feet)
Pleistocene (?)
Marine terrace(?) deposit
6 Sand, light-tan, fine to coarse; contact with unit 5 is
fairly sharp; unit 6 is softer than unit 5 and common-
ly weathers back, exposing a shelf-like surface at the
top of unit 5 ...................................... .. ......-..- ......... . 12
Citronelle Formation
5 Sand, reddish-brown, fine to very coarse, pebbly; very
poorly sorted; pebbles angular to well rounded,
quartz; 1 to 3 percent dark minerals; units 5 and 4
are hard and form a vertical cliff .................... ........... 16
4 Sand, mostly rusty-reddish-brown, some white, irreg-
ularly intermingled and as alternating strata; med-
ium to medium coarse, pebbly sand whose grains
are angular to subangular; 1 to 3 percent dark min-
erals; harder than underlying units; clay tubes and
clay fragments (see unit 2) very scarce; grades up-
ward into unit 5 .............. ... .. .............. ..... 10
3 Sand, white to gray with layers and irregular patches
of rust red; very fine to very coarse pebbly; abundant
clay tubes as in unit 2 but more poorly preserved;
clay layers and fragments much less numerous than
in unit 2, with fine muscovite flakes abundant along
bedding planes; forms relatively gentle slope leading
from base of unit 4 ................................................... 16
2 Sand, very white; soft, loose; grains subangular, poorly
sorted, ranging from very fine to very coarse, nearly
all quartz; a few white quartz pebbles up to a fourth
inch in diameter; 1 to 2 percent black minerals; sand
is cross bedded on a small scale. The most distinctive
feature is pure, white clay (kaolin) occurring as: (1)
angular chips and blocky fragments up to 4 inches
long; (2) discontinuous beds 1 to 2 inches thick and
as much as 20 feet long, some of which consist of
tabular, irregularly shaped fragments, like "islands"

FLORIDA GEOLOGICAL SURVEY BULLETIN No, 46

Thickness
Unit (Feet)
in the enclosing sand; and (3) abundant tubular fos-
sil burrows of Callianassa(?) sp. ("ghost shrimp")
which are % to I inch in diameter and as long as 1
foot, consisting of soft white kaolinite and sand; the
tubes are embedded vertically in the enclosing sand 13
1 Covered down to level of Escambia Bay ................. 11

Total exposed section ................ 67

There is a striking similarity between this section and the sequence
of beds that has been designated as Citronelle in the Florida Penin-
sula. Pirkle (1960, p. 1389) states that:
"In Putnam County the normal sequence of strata within
the Citronelle materials, from the surface downward, consists
of loose sands, a zone of red and yellow clayey sands, and an
underlying zone of white, clayey sands... The white, clayey
sands, often referred to as the kaolin zone, consist mostly of
quartz sand with a binder of kaolinite ... The kaolin zone
rests unconformably on the Hawthorne formation. AU or parts
of this sequence of Citronelle sediments can be traced by ex-
posure from Clay County through Putnam County, the eastern
part of Marion County, Lake County and south through Polk
County... Occasional stringers and lenses containing a high
percentage of kaolinite occur in the lower part of these Citro-
nelle sediments... During deposition the sediments were peri-
odically exposed to the atmosphere, resulting in the desiccation
of some of the stringers and small lenses of kaolin. Some of the
hardened lenses were fragmented by current action into kaolin
blocks and balls. Such blocks and balls were subsequently in-
corporated in Citronelle clayey sands as deposition of that
formation continued."
During a visit to Putnam County, the writer discovered poorly
preserved clay burrows of Callianassa(?) in the Citronelle beds re-
ferred to by Pirkle, thus adding still another similarity between these
beds and those described in the measured section above, although the
resemblance between the two sections in Escambia and Putnam
counties is striking, further work will be needed to definitely establish
the correlation.

80

GEOLOGY OF ESCAMBIA AND SANTA ROSA COUNTIES, FLORIDA 81

Fossils. WOOD AND POLLEN Parts of the Citronelle For-
mation of the western Panhandle contain abundant remains of trees
and other woody plants. This material occurs in two forms: as zones
of charcoal and carbonaceous material, and as logs and twigs that
have not been carbonized. Samples from well W-4312 in northeastern
Escambia County contain soft black carbonaceous lumps at 190 and
280 feet; in the interval 340-360 feet, an estimated 50 percent of the
unwashed samples consists of carbonized wood fragments. A thin,
carbonaceous layer may be seen in roadcuts, stream banks, and rail-
road cuts at many places throughout Escambia and Santa Rosa
counties. Whether this actually represents a single, regionally exten-
sive layer or several different layers could not be determined. The
thickest carbonaceous zone observed was at an altitude of about 50
feet on the north side of Canoe Creek about 4 miles southwest of
Century in northeastern Escambia County. where U. S. Highway 29
crosses the creek. Here, a zone of highly carbonaceous clayey earth
and gravel containing hits of coal and twigs was exposed in the side
of a small artificial drainage cut until later construction work obliter-
ated the exposure. The zone was 2 feet thick, with a sharp but irregu-
lar upper contact, and graded downward into sparsely carbonaceous
sand at the bottom of the cut. About 8 miles northeast of this locality,
a 1-foot carbonaceous zone containing abundant charcoal is exposed
at an altitude of about 200 feet along both sides of a deep railroad
cut where U. S. Highway 29 crosses the Louisville and Nashville Rail-
road northeast of Flomaton, Ala. It is not unreasonable to suppose
that this bed and the one at Canoe Creek may be the same: if so, it
would have a southwestward dip of about 18 feet per mile, which
agrees quite well with the regional dip of the Citronelle in Escambia
and Santa Rosa counties. Well driller Lehmon ("Tex") Spillers (oral
communication, April 1961) of Pensacola stated that at Escambia
Farms in northern Okaloosa County he drilled through a layer of
"burnt wood or charcoal hard as a brick" at a depth of 100-125 feet.
He added that most wells in that general area encounter this same
carbonaceous zone. These zones of carbonaceous material may have
been the result of ancient forest fires.
The second type of fossil wood in the Citronelle of west Florida
is uncarbonized material. At a few places, notably south of Munson
in Santa Rosa County, fragments of wood and twigs replaced by
limonite were found among lag gravel on the surface of the ground.
Of considerably more interest, however, are the numerous logs that
well drillers encounter during the drilling of water wells in western

FLORIDA GEOLOGICAL SURVEY BULLETIN NO. 46

Florida. Spillers (oral communication, April 1961) reports that he
has drilled through many fossil logs in Okaloosa, Santa Rosa, and
Escambia counties, Fla., and in southern Baldwin County, Ala. In
the Pensacola area, he says, logs are generally encountered at a depth
of about 200 feet and are commonly embedded in a "fine, silty, muddy
sand like an old lake bottom." Near Robertsdale in southern Bald-
win County, Ala., Spillers drilled through a log 3 feet thick between
depths of 80 to 100 feet, and "enough pulp to fill a couple of wash-
tubs" came up the drill hole, clogging the mud pit and stopping up
the pump. Other drillers have reported drilling into logs at depths of
50 to 100 feet at various places in the western Panhandle.
In 1958, samples were collected from the Citronelle Formation at
its type locality and at several places in Escambia and Santa Rosa
counties, Florida as well as Escambia County, Alabama, in hopes of
determining the age of this formation. The samples were studied by
Estella Leopold of the U. S. Geological Survey in Denver. Fossil pollen
were found in only three of the samples, none of which was from the
type locality. Two of these samples contained polen which may be of
significance for the age of the Citronelle in western Florida. Miss Leo-
pold's interpretation of these samples, quoted from her report, is
given below.
"Field No. OTM-41-58: Citronelle formation, about...
[345] feet above base; locality, west bank of Escambia River,
% mile S. E. Chemstrand Corp. Plant, 10 miles N. of Pensa-
cola, 3.5 miles N. E. of Gonzalez; (assigned USGS Paleobot.
loc. no. D1378); sample dark gray carbonaceous clay. Assem-
blage predominantly pine pollen with sweet gum and holly. An
association of Drosera (sundew) and Sphagnum (bog moss)
which are generally characteristic of bogs of the North Tem-
perate Zone, reach their southern limit in eastern USA on hard
pan boggy places in open forest or flat woods. They are gener-
ally associated in Florida with huckleberries (which might be
represented here as Ericales, undet.) and also with several
pines; slash, long-leaved and loblolly. Pine is the dominant
form in this sample, but at present it is not possible to distin-
guish species from pine pollen. A second swamp type is sug-
gested by the emergent aquatic Eriocaulon which grows in
Florida primarily in wet prairies that get occasional flooding.
It is generally associated with grasses, sedges and composites,
all of which are present in your assemblage.
"An occurrence of the shrub Dirca (leatherwood) is of great

GCotLxOY or ESCAMRIIA AND SANTA Ro A COUNTIES. FROIAIDA

interest because it is associated with rich hardwood forest and
ranges from northernmmt Florida northward. The presence
of Judans (walnut) here, but not lower in the section is of
special interest becauw the genus now ranges from central
Alabama northward except for a single relict population in
Escambia County. A final significant northern plant in this
assemblage is Tsuga hemlock) which now occurs no farther
south than the highlands of N. Alabama and Georgia.
"Field No. OTM-50-58: Citronelle formation, about...[155]
feet above the base; locality: east bank of Big Coldwater River,
at mouth of Earnest Mill Creek; 5.8 miles N. (by river) from
junction of Big Coldwater and Blackwater Rivers, Santa
Rosa County, Florida. SW NE sec. 30, T, 3 N., R. 27 W.
(assigned USGS Paleobot. loc, no. D1379). Predominantly
pollen of pine and grass, with sweetgum, holly, oak, alder, etc.,
and (significantly) small amounts of hemlock pollen. As in
D1378, Drosera. Sphagnum, Ericales are preenL Northern
elements include all those mentioned for D1378 except Dirca,
and two additional ones; spruce, which has a southern limit in
eastern U. S. equivalent to that of Tsuga, and Xanthoxylon,
now reaching central Alabama at the southern limit of its
range."
Figure 20 shows the position of this latter sample in the bank of
of the Coldwater River.
Misa Leopold concludes that the flora described above provides
"clear fossil evidence of a Quaternary age for the middle and upper
parts of the Citronelle formation in westernmost Florida." A com-
plete list of the forms identified by Miss Leopold in the above samples
is given in Appendix C at the end of this report.
INVERTEBRATE FOSSILS Carlston (1950, p. 1120) states
that "no invertebrate or vertebrate fossils have been found in the
Citronelle formation." It is largely for this reason that the age of the
formation has never been conclusively established. In Escambia and
Santa Rosa counties. Florida. the great majority of well samples from
the Citronelle Formation are nonfossiliferous. However, a few frag.
ments of mollusk shells were noted in samples of the formation from
wells in the central and northern parts of the area, at depths ranging
from 20 to 300 feet below the surface (see below). These shell frag-
ments were too weathered and broken to permit identification. More
significant is the occurrence near the Gulf of abundant fossils in sand

8&

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

.... Altitude 40 ft.
5 Sand rust-brwnm, fifU to media, hard

2.5 ft Sand, wits end yellowish-brown, vry fin, soft
Clay, Ltsb--gray and purplibh, Incerbodded
with very fine-grained clayey sand containing
9.3 ft. specks of charcoal; a four-inch bed of black
7-. clay in upper part
1 C.clay, very black, with bits of charcoal
1P. olln Sie Dpl 1379
Sand, white to yellovwih-broni very fine
--.-- Clay. light to dark-gray
9 ft --- Sand bar
.'-. Coldwater
River
SOUTH IORI1
Figure 20.-Diagranlmatit s cLion of Citronelle Formation explsel in river
hank just south of junction of Coldwater River and Earnest Mill
Crrk. Santa Rosa County, showing location of pollen sample
D1379.

and clay beds below about 25 feet. Because of the difficulty of dis-
tinguishing the sediments of the Citronelle from deposits formed dur-
ing the latter part of the Pleistocene, such as the marine terrace
deposits, exact correlation of these fossiliferous beds is uncertain.
However, these beds may be the marine equivalent of the inland
fluvial faces of the Citronelle. Unfortunately, time did not permit
identification of the fossils from these beds which might have aided
in their correlation. Because the invertebrate fossils in Escambia and
Santa Rosa counties are apparently the only ones known from the
Citronelle Formation, a list of these occurrences is given below. Exact
locations of the wells are given in the well table (Appendix A).
Central and northern parts of the area
Escambia County: W-5009 -a single shell fragment at 40-50 feet.
Clay pit of a brick company at Molino- obscure, unidentifi-
able casts of marine gastropods and pelecypods reported by
Cooke and Mossom (1929, p. 147).
Santa Rosa County: W-2900 one fragment of a ribbed pelecypod
at 40 to 50 feet.
W-3048 weathered shell fragments in three samples in the
interval 20 to 60 feet.
W-3455 scarce shell fragments at 130 to 170 feet.
W-4357 very scarce shell fragments at 300 feet.

84

GEOLOGY OF ESCAMBIA AND SANTA RosA COUNTIES, FLORIDA 85

Southern part of the area
Escambia County: W-4091 abundant shells of tiny gastropods and
pelecypods and common foraminifers including Elphidium sp.
in clay bed at 60 to 80 feet.
W-3324 fossils abundant below a depth of 25 feet; gastro-
pods and pelecypods, including Area sp.; ostracods; barna-
cles; echinoid spines; foraminifers including Elphidium sp.
Santa Rosa County: W-4122 scarce fragments of small and large
pelecypods from 130 feet downward; shark's tooth at 215 feet.
W-2339 abundant mollusks (see table 12).

Table 12.- Mollusks found in the Citronelle Formation (well W-2339) on
Fairpoint Peninsula, Santa Rosa County, Florida.
Depth in
feet be-
Pelcypodta aOtropoda feet bl
surface
Divaricela quadrisulcata Orbigny Pyramidella crenlata Holmei 61-64
Macrocallita maculata LUnne supycon
Macrocaltlata nlnbosa Solander
Loripinus chrysoatoma

Daoax varlabte Say Cancellaria reticulata Lnne 5.-72
Laervlcrdum I1etgatum Linne Cerithuim lUtratum Bdfc
Lucina penBsylvanlca Line Conurl lorldanui Gabb
Pecten c. P. raveneli Dall Cymatium chloroatonum Lamarck
Plicatula gibbota Lamarck Marginella cf M cornea
Ouiv sayana Ravenel
Olve ll cL O mutica Say
Btrombus alatus Gmelin
Terebra dislocaa Say
Turritella c. T. exaleta Linn

Chlone intappurprea Conrad Crepldula ap- ? 79-77

Area C A pu ata Say Poliices duplicate Say 78-83
Peclen Irradians Lamarck Utro~salp clnerea Say
Trachycardium IsocardLa Shuttleworth

The mollusks in table 12 were identified by Ralph Heath in sam-
ples from U. S. Geological Survey water test well W-2339 (see well
table, Appendix A) near Gulf Breeze on Fairpoint Peninsula, Santa
Rosa County. This well is about 4 miles southeast of Pensacola. The
assemblage is of Pleistocene to Recent age.
A distinctive feature of the Citronelle beds in Escambia and Santa
Rosa counties is the presence of large numbers of fossil burrows

FLORIDA GEOLOGICAL SURVEY BULLETIN No. 46

(Marsh, 1963). According to J. W. Hoyt (oral communication, April
12. 1963), the burrow were probably constructed by the "'ghbot
shrimp" CalUianassa which may well be the same as what has been
called Halymenites. Caianssa ranges from Jurassic to Recent. Sim-
ilar burrows were found by R. O. Vernon, J. W. Yon, Jr., and W. D.
Reves of the Florida Geological Survey in coarse clayey sands in
Liberty, Hamilton, Columbia, Putnam, and Lake counties. The bur-
rows are tubes of white kaolinite % to 1 inches in diameter and
as much as 5% feet long. A few have bulbous enlargements at the
lower end, which probably served as the living chamber for the shrimp.
Age of the Citronelle Formation. On the basis of fossil leaves
and plants found in a clay bed about 6 miles south of Citronelle,
Berry (1916) concluded that the Citronelle Formation was of Pliocene
age. However, Doering (1935, p. 658) pointed out that the leaf bed
was not in the Citronelle but was actually part of the underlying
formation. This belief was upheld by later investigators, including
Roy (1939, p. 1553-1559) and Carlston (1951, p. 1882-1892), who
concluded that the leaf bed is separated from the Citronelle by an
unconformity. Stringfield and LaMoreaux (1957, p. 742) are of the
opinion that even though the leaf bed may be situated below an
unconformity, this does not preclude the possibility that it is within
the Citronelle. They point out that a similar clay bed containing
plants identified by Berry as Pliocene, which is found at Red Bluff on
Perdido Bay in Baldwin County, Alabama, is underlain by sand and
clay typical of the Citronelle and therefore lies within that formation.
However, Doering (1958, p. 764-786) reviewed the entire Citronelle
age problem and questioned Berry's assignment of the plant fossils
at Red Bluff and Citronelle, Alabama, to the Pliocene. He maintained
(op. cit. p. 765) that "no more than a pre-Nebraskan correlation is
actually warranted by the fossil data" and that "on the fossil evidence
the Citronelle can be assigned as readily to the early Pleistocene as
the late Pliocene, and that other evidence gives substantial support
to such an assignment and makes it appear necessary to include a
pre-Nebraskan time interval in the early Pleistocene." Doering points
out (op. cit) that in 1948, the 18th International Geological Con-
gres redefined the Pleistocene to include this pre-Nebraskan inter-
val In Doering's (op. cit) opinion the "Pliocene" leaves identified by
Berry from the Citronelle may well have originated in this preglacial
part of the Pleistocene.
Further work will have to be done before the age of the Citronelle
Formation can be definitely established. Based on the meager evidence

86

GCOLOrY OF EsCAMBIA AND SANTA ROSA COUNTIES, FLORIDA

available from Escambia and Santa Rosa counties (see section on
fossil wood and polen above), however, the author tends to favor
Doering's interpretation of the CitroneDe as early Pleistocene.
Contacts and electric-Iog expression.-The Citronelle Forma-
tion lies unconformably upon the Miocene coarse clastics in most of
the area and upon the Pensacola Clay just north and east of Pensa.
cola. Pleistocene marine terrace deposits of unknown but probably
small thickness disconformably cap the Citronelle Formation. The
electric-log expression of the Citronelle is the same as that of the
Miocene coarse plastics: high resistivities opposite sand beds, alter-
nating with relatively low resistivities opposite clay beds.

QUATERNARY SYSTEM
PLIISTOCENE SERIES
Marine Terrace Depoimt
During the invasions of the sea upon the land in the Peistocene
Epoch, the Citronelle deposits were reworked and mixed with new
deposits of similar materials. As a result the Citronelle beds and the
marine terrace deposits that presumably cap them in much of the area
are generally difficult, if not impossible, to distinguish from each other.
In a few places, such as the bluffs along the west side of Escambia
Bay (see measured section, p. 79), some difference were noted.
Here, the sand of the terrace (?) deposits is softer and less consoli-
dated, contains much fewer (if any) pebbles, and contains much less
clay than the CitroneUe.
Previous workers, notably Cooke, (1945, p. 273-311) have given
a different formation name for the terrace deposits that underlie each
of the Pleistocene marine terraces. The propriety of this practice is
questionable for several reasons. These "formations" do not conform
to the accepted definition of a geologic formation as a lithologic unit
that can be distinguished with sufficient ease from adjacent units to be
mappable; in fact, as Carlston (1950, p. 1120) points out, it is "vir-
tually impossible" to distinguish the Pleistocene sand and gravel
from that of the Citronelle. Cooke's terrace-deposit "formations" are
defined solely on the basis of altitude above sea level, not lithology.
Cooke himself (op. cit.) indicates clearly the questionable basis on
which these "formations" rest, as shown by the following quotations
of the passages in which he introduced them:
"The Brandywine (now called Hazlehurst) formation in
Florida is believed to be predominantly sandy. Little is known
about its variations... The Coharie formation is probably

87

	Cover
	Title Page
	Letter of transmittal
	Table of Contents
	List of Illustrations
	List of Tables
	Abstract
	Introduction
	Stratigraphy
	Quarternary System
	Structure
	Economic geology
	Appendix A. List of wells used...
	Appendix B. Logs of selected wells...
	Appendix C. List of fossil pollen...
	Reference

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