GEOLOGICAL SURVEY CIRCULAR 91 

January 1951 

PRELIMINARY REPORT 

ON BURIED PRE-MESOZOIC ROCKS 

IN FLORIDA AND ADJACENT STATES 

By 

Paul L. Applin 
UNITED STATES DEPARTMENT OF THE· INTERIOR 

Oscar L. Chapman, Secretary 

GEOLOGICAL SURVEY 

W. E. Wrather, Director 

Washington, D. C. 

Free on application to the Geological Survey, Washinil:ton 25. D. C. 
CONTENTS 

Page Page 

Introduction . . . . . . . . • . . . • . . . . . . . . . . . . . • . . . . 1 Pre-Mesozoic rocks--Continued 

Acknowledgments . . . . . . . . . . . . . . . • . . . . . 3 West-central Alabama area........ 13 

Florida-Georgia area • . • . • . . • . . . . • 13 

Triassic(?) diabase and basalt................ 15 

Pre-Mesozoic structure of the Florida 

Subsurface structure of the Florida peninsula. • 3 

Pre-Mesozoic rocks........................ 5 

Granite, diorite and metamorphic rocks.. 5 

Rhyolitic lavas and pyroclastic rocks • . • • 8 

Paleozoic sedimentary rocks . . • . . . • . . . • 11 

peninsula . . . . . . . . . . . • . . • . . • . • . . . . . . . . . . • . 17 

References . . • . . . . . . . . . . . . . • . . . . . . . . . • • . . . • 17 

ILLUSTRATIONS 

Page 

Fiqure 1. Map of Florida and parts of Alabama and Georgia showing diagrammatically the subsurface 

distribution of the pr~Mesozoic rocks . . . . • • • • • . . . • • • • . • . . • • • . • . . . • . • . • . • . • • . . . • • • • . • . . . 2 

2. Map of Florida and parts of Alabama and Georgia showinq the configuration of the surface 

of. the pre-Mesozoic rocks .••.••.•.••..•..• • •.•.••.•.••...••..•.•••.•. ., .•••..•••• ~..... 4 

3. North-south structural cross section from outcrop of crystalline rocks in central Georgia to 

Big. Pine Key, Monroe County, Fla. Section along line A-A 1 (fig. 1) • • • . . . • • . . . • . • . . . • . • . • • • 6 

4. West-east structural cross section from Jefferson County to Flaqler County, Fla. Section 

along line B-B 1 (fig. 1) • • • . • • • • • • • • • • • • • • . • • . • • • • • • . . . • . . . . . • • • • • • • • • • • . • • • • . . • • • . • • • . • • 10 

5. Diagrammatic cross section along part of line A-A 1 (fig. 1) from Atkinson County, Ga., to 

Highlands County, Fla., showing an interpretation of the structure at the e~d of the' 

Paleozoic era ......•.•.•..•••....•• ·..•. • • • ..• • • . . . • • • • . • . • • • • • • • • • . • . • • • • • . . . • . • • • . . . . 12 

TABLES 

Page 

Table 1. Data on wells penetrating granite, diorite and metamorphic rocks in Alabama, Florida and 

2. 

Georgia Coastal Plain .••.••.....•.•..•..•..•....•.•..............•..... ; . • . . . • . . ... . . . • . 19 

Data on wells penetrating rhyolitic lavas and pyroclastic rocks in central Florida and southeast Georgia . . . . . . . . . • . . . . • •....••..•...•....•......•.•............•.... ~ .......•.• ~ . 21 

3. Data on wells penetrating Paleozoic sedimentary rocks in Alabama, Florida, and Georgia 

Coastal Plain . • . . . . . . . • . . . . . . • . . • . . • • • • . • • . . • . • . • . . . . • • . . . • • . • ... . • . • • . • . . . . . • . . . • . . . . 22 

4. Data on wells encountering Triassic(?) diabase and basalt in Alabama, Florida and Georgia 

Coastal Plain . . . . . . . • . • . .. • . . . . • . . • . . . • . . . . • • • . • . • . . • • • . . . . . . • . • . . . . . . • . . . . . • • . • • . • . . . . 26 

Data on siqnificant deep wells in Alabama, Florida, and Georqia Coastal Plain that did not 

reach pre-Mesozoic rocks .................................... .' .....•.....•.•.••..••.••.. •. 28 

5. 

- i-

PRELIMINARY REPORT ON BURIED PRE-MESOWIC ROCKS 

IN FLORIDA AND ADJACENT STATES 

By 

Paul L. Applin 

INTRODUCTION 

Since the year 1900 more than 500 oil and gas 

test wells have been drilled in the Coastal Plain of 

Florida, Alabama, and Georgia. The wells range 

in depth from a few hundred feet to more than 15,000 

feet. The deepest tests in the southeastern Coastal 

Plain are Gulf Oil Corporation's State of Florida well 

No. 1 (sec. 2, T. 67 S., R. 29 E.), on Big Pine Key, 

Monroe County, Fla., which reached a total depth of 

15; 455 feet, and Humble Oil & Refining Company's 

J. R. Williams well No. 2 (sec. 21, T. 6 N., R. 4 W.), 

Washington County, Ala., abandoned at the total depth 

of 15, 659 feet. Both of these wells were completed 

in rocks of probable Jurassic age. 

By fa:r: the greater number of oil test wells in 

the southeastern States penetrated only Cenozoic and 

Mesozoic rocks, but infurmation is available on 78 

wildcat wells that were drilled through those rocks 

into older rocks of a wide variety of types. Granite, 

diorite, metamorphic rocks, rhyolite, pyroclastic 

rocks, and Paleozoic strata have been encountered 

in different wells scattered throughout the region. 

All these pre-Mesozoic rocks are grouped together 

under the inclusive term "basement" rocks by some 

of the geologists. who are conducting subsurface studies 

in connection with oil exploration. Most of the wells 

penetrating the pre-Mesozoic rocks in the southeastern 

Coastal Plain were drilled within the past decade, many 

of "Ulem within the past five years, and from a number 

of the wells unusually complete sets of cores of the 

older rocks were obtained.· Although the cores furnished 

a wealth of new subsurface data, new problems were 

also raised, the sol uti on of which can be furnished 

only by more and deeper tests. The stratigraphy and 

structure of the ancient rocks in the southeastern region 

bid fair to continue to be a fruitful field for investigation, 

and samples from additional tests are likely to brinq 

to light new data that will require revision of some of 

the tentative conclusions and interpretations here 

expressed. 

Based largely on petrographic and petrologic study 

of cores and cuttings, this repol.'t is an initial attempt 

to integrate the data from the widely dispersed wells 

that reveal a diverse lithologic pattern in the preMesozoic rocks of the southeastern Coastal Plain. The 

discovery of buried volcanic and crystalline rocks and 

Paleozoic strata in Florida and southern Georgia is a 

comparatively recent addition to geologic kriowledge. 

These new data may revise earlier ideas about certain 

paleogeographic boundaries and permit increased precision in the delineation of ancient landmasses and 

basins of sedimentati.'on. In connection with exploration 

for oil in the southeastern States, an understanding of 

the geology of the pre-Mesozoic rocks is important 

because they comprise the floor apon which the Mesozoic 

1 

strata were deposited. In this region, the Mesozoic 

strata are considered to be the ones most likely to 

contain reservoirs and structural features favorable 

for accumulation. Geophysical prospecting and 

interpretation of geophysical data may benefit from a 

record of the variations in depth and composition of 

the different kinds of pre-Mesozoic rocks. 

The report proposes a three.fold classification 

for the buried pre-Mesozoic rocks in Florida, the 

Coastal Plain of Georgia, and southeastern Alabama. 

These rocks are classified as: dominantly marine 

sedimentary Paleozoic rocks, which on the basis of 

faunal evidence, range in age from late Cambrian or 

early Ordovician to Silurian (Howell and Richards, 

1949); rhyolitic lavas and pyroclastic rocks that are 

tentatively classified as early Paleozoic or preCambrian; and granite, diorite, and metamorphic rocks, 

which are probably in part pre-Cambrian and in part 

of Paleozoic age. Penetration has not been sufficient 

to show definitely the vertical sequence of the different 

rock types that are encountered in different wells. 

The report discusses tentative conclusions on.the 

sequence of the types of rocks in the foregoing classification. 

In the western-and central parts of the Alabama 

Coastal Plain, the downward sequence of the buried 

pre-Mesozoic rocks is Paleozoic sedimentary rocks 

that range in age from Pennsylvanian to Ordovician and 

Cambrian, and metamorphic rocks that are possibly 

pre-Cambrian. Rhyolitic lavas and pyroclastic rocks 

similar to those encountered in wells in the central 

part of peninsular Florida and southeastern Georgia 

have not been discovered in Alabama. 

In connection with the study of the pre-Mesozoic 

rocks of the southeastern region, this report also 

discusses the intrusions and flows of diabase and basalt 

encountered in 18 wells. Data from a part of the wells 

point to a period of igneous activity during the early 

Mesozoic; in other wells the time of emplacement of 

the diabase has been less definitely determined and 

may be in part early Mesozoic and in part Paleozoic. 

Tables 1, 2 and 3 show data on ·78 wells that 

penetrated pre-Mesozoic rocks in the Coastal Plain 

of Alabama, Florida, and Georgia; table 4 shows data 

on 18 wells that encountered Triassic(?) diabase and 

basalt; and table 5 presents data on 12 significant 

deep wells that did not reach the pre-Mesozoic rocks. 

The geographic locations of the wells are shown on ; 

figures 1 and 2; figure 1 also shows diagrammatically 

the writer's interpretation of the subsurface distrib~tion 

of the different kinds of pre-Mesozoic rocks. The 

geographic distribution of the rock types penetrated in 
EXPLANATION 

PRE - MESOZOIC ROCKS 

Silurian and Ordovician 

Sedimentary rocks 

Paleozoic {?) or Pre-Cambrian {?) 

Rhyolite, tuff, and agglomerate 

Pre - Cambrian {?) 

Granite, diorite, and metamorphic rocks 

WELL SYMBOLS 

• Wells encountering Paleozoic strata . 

"' Wells encountering rhyolite, tuff, and agglomerate. 

::.: Wells encountering gran ite, diorite, and metamorphic rocks. 

.. Well encountering Paleozoic strata overly ing rhyol itic rocks. 

-o- Wells encountering Triassic{?) diabase and basalt. 

0 Significant deep wells that did not reoch pre-Mesozoic rocks. 

Line A-A' shows location of cross-section on f igure 3. 

Line B-8' shows location of cross-section on figure 4. 

0 25 

f::::===d 

50 75 

f::::===d 

Figure 1.--Map of Florida and parts of Alabama and Georgia showing diagrammatically the 

subsurfa ce distribution of the pre-Mesozoic rocks 
the wells listed in tables 1-4 is summarized as follows: 

Ala. Fla. Ga. Total i 

Pre-Mesozoic rocks: 

Granite, diorite, and metamorphic rocks ....................... 4 3 11 18 

Rhyolitic lavas and pyroclastic rocks ...................•.... 8 2 10 

Paleozoic sedimentary rocks .......... 7 37 7 51 

Total ............. . ... .. . . . . . . . . lT ·w m 'rn* 

Triassic(?) diabase and basalt .............. 2 10 6 18 

*Sun Oil Company's Camp well No. 1 (tables 2 and 3, and fig. 1), 

Marion County, Fla., penetrated volcanic agglomerate or tuff underlying Paleozoic sedimentary rocks. 

The depth of penetration (tables 1, 2, and 3) into 

the pre-Mesozoic rocks varies widely, ranging from 

a few feet in many wells to 4, 553 feet of Paleozoic 

strata in a well in Pickens County, Ala. Nearly half 

the wells shown in the tables penetrated the preMesozoic rocks to depths of 100 feet or more. Most 

of these wells encountered Paleozoic sedimentary 

rocks; whereas only about a half-dozen wells penetrated the nonsedimentary rocks to depths of more than 

100 feet. · 

Detailed petrographic analyses of the nonsedimentary rocks are not given in this report but it is 

anticipated that they will appear later in a separate 

publication by others. Other geologists of the Geological Survey are also now. conducting detailed 

stratigraphic and structural studies of the Paleozoic 

sedimentary rocks of Florida and Georgia, basing 

their investigations on the lithologic character and 

faunal content of many well samples. The results of 

these investigations, which are still in progress, are 

expected to be published later. 

Acknowledgments 

Geologists employed by oil companies and by 

the Florida Geological Survey have been most generous 

and helpful in making available for study an exceptionally complete collection of core samples of the 

nonsedimentary rocks and Paleozoic strata from oil 

·test wells in the southeastern States. Sincere.thanks 

are expressed to the following geologists, who contributed samples used in the preparation of this report: 

I. J. Reed and Lois Shulz Herring, formerly with 

The California Co., Tallahassee, Fla.; J. E. Banks, 

Coastal Petroleum Co., Tallahassee; James A. Tierney 

and M. F. Kirby, Gulf Refining Co., Tallahassee; 

E. A. Murchison, T. J. Burnett, and W. C. Blackburn, 

Humble Oil & Refining Co. , Tallahassee; H. A. Sellin, 

Magnolia Petroleum Co:, Tallahassee; H. G. Walter, 

The Ohio Oil Co., Tallahassee; T. D. Rodgers, 

Stanolind Oil & Gas Co., Tallahassee; D. J. Munroe 

and Louise Jordan, Sun Oil Co., Tallahassee; L. C. 

Kirby, Tidewater-Associated Oil Co. , Tallahassee; 

Herman Gunter, Director, Florida Geological Survey, 

Tallahassee; B. W. Blanpied and Roy T. Hazzard, 

Gulf Refining Co., Shreveport, La.; F. W. Rolshausen 

and E. D. Pressler, Humble Oil & Refining Co., 

Houston, Tex.; Earl Westmoreland, Seaboard Oil Co., 

Jackson, Miss.; D. Hoye Eargle and P. E. Lamoreaux, 

U. S. Geological Survey, University, Ala. 

The writer is particularly indebted to Charles 

Milton, Geochemist, U. S. Geolagical Survey, 

- 3 -

Washington, D. C. , for determinations and petrographic studies of samples of the nonsedimentary rocks 

of the southeastern region, and to Frank F. Grout, 

Visiting Professor of Geology, Florida State University, 

Tallahassee, for helpful suggestions and criticisms 

in connection with the preparation of this report. · 

Sincere appreciation is expressed to Robert 0. 

Vernon and James L. Calver, geologists, Florida 

Geological Survey, Tallahassee, for assistance in 

identifying samples of igneous rocks from a number 

of wells in Florida and Georgia, and for helpful 

discussions during the progress of the work on the 

pre-Mesozoic rocks. 

Thanks for reading and criticizing the manuscript 

are due Carle H. Dane, Watson H. Monroe, Josiah 

Bridge, and Jean M. Berdan, U. S. Geological Survey, 

Washington, D. C. 

SUBSURFACE STRUCTURE 

OF THE FLORIDA PENINSULA 

The map (fig. 2) and cross sections A-A' (fig. 

3) and B-B' (fig. 4) illustrate clearly the large anticlinal fold or arch that is the dominant subsurface 

structural feature of eastern Florida and an adjacent 

part of southeastern Georgia. The anticlinal fold, 

or arch, which is approximately 275 miles long, 

trends south-southeastward and· forms the axis of the 

Florida peninsula as far south as the latitude of Lake 

Okeechobee. In this report the name Peninsular arch 

is used to designate this dominant subsurface structural feature. The area of regional downwarping 

south of the Peninsular arch was designated the South 

Florida embayment by Pressler (1947, p. 1856) and 

the South Florida basin by Carsey (1950, fig. 3). By 

means of contours drawn at 1, 000 foot intervals, 

figure 2 shows the configuration of. the Peninsular 

arch at the surface of the pre-Mesozoic rocks,. A 

profile of the arch is shown in cross section A-A' 

(fig. 3), which is drawn from north to south apprc)ximately parallel to the axis of the peninsula; cross 

section B-B' (fig. 4), in the northern part of the 

peninsula, is drawn from west to east along a line 

that is approximately at right angles to cross section 

A-A'. . 

Reference was made to a regional arch in 

eastern Florida in a U. S. Geological Survey press 

bulletin (Mossom, 1926, p. 220) issued a0out 19·20: 

The arch was not named in the press bulletin, but 
EXPLANATION 

WELL SYMBOLS 

• Wells encountering Paleozoic strata . 

'f Wells encountering rhyolite, tuff, and agglomerate. 

• Wells encountering granite, diorite, and metamorphic rocks. 

If Well encountering Paleozoic strata overlying rhyolitic rocks. 

<:r Wells encountering Triassic(?) diabase and basalt. 

o Significant deep wells that did not reach pre-Mesozoic rocks. 

Line A-A' shows location of cross-section on figure 3. 

Line B-8' shows location of cross-sect ion on figure 4. 

Contour interval 1,000 feet. Da tum is sea-level. 

0 25 !=====~ 

50 75 !=====~ 

t. Augustine 

F igure 2.--Map of Florida and parts of Alabama and Ge orgia s howing the configura tion of 

of the s urface of the pre-Mesozoic rocks 

98 

0 
two locally high areas were named and described. The 

larger and higher area, in eastern Levy County, was 

called the Ocala uplift. SUbsequent investigations 

have shown that the Ocala uplift centers around outcrops 

of Ocala limestone (upper Eocene) and Avon Park 

limestone (middle Eocene) in Citrus, Dixie, and Levy 

Counties on the west coast of the peninsula. The axis 

of the Ocala uplift does not coincide with the axis of 

the Peninsular arch, and surface and subsurface data 

show the absence of close structural relations between 

the two features. A report in preparation by geologists 

of the Florida Geological Survey (Vernon, 1950) will 

say that the Ocala uplift is a small flexure developed on the west flank of the Peninsular a:rch. The uplift 

is probably the result of post-Eocene disturbances 

in the surface and shallow subsurface formations. 

The search for oil in Florida directed attention 

to the regional subsurface structure that occupies 

two-thirds ·of the peninsula. Possibly because this 

structure had no specific designation, geologists 

enqaqed in subsurface mapping in Florida extended the 

term Ocala uplift to apply to the regional arch. In 

order to. clarify the structural terminology in Florida, 

the writer suqgests that the name Ocala uplift. should. be 

restricted to the local surface feature. 

PRE-MESOZOIC ROCKS 

Granite, diorite; and metamorphic rocks 

Fifteen wells in the Coastal Plain of Alabama and 

Georqia and three wells in the cent:ral part of peninsular 

Florida terminated in crystalline rocks that are classified as qranite, diorite, and metamor.phic rocks 

(table 1 and fiq. 1). 

Published reports supplied data (table 1) on 10 

wells in Alabama and Georqia from which samples were not available; petroqraphic determinations of 

crystalline rocks encountered in five wells are shown 

in table 1 and in the follow~nq list: 

Well Name of well 

No. 

· The crystalline rocks encountered in wells in the 

Alabama and Georgia Coastal Plain. represent the 

buried extension of the rocks of the southern Appalachian Piedmont, and like their outcropping _counterparts the buried rocks are probably in part preCambrian and in part of Paleozoic age. Nearly all 

the wells are a relatively short distance south of the · Piedmont. The three most southerly ones are the 

McConnico well, Wilcox County, Ala., which is 60 

miles southwest of the outcrop of the crystalline rocks, 

and the two Adams-McCaskill wells, Pierce County, 

Ga. , 125 miles southeast of the Fall Line. By means of contours drawn at 1, 000 foot intervals through the 

widely scattered wells just south of the Piedmont, 

figure 2 show~ the approximate configuration of the 

surface of the buried crystalline rocks in Georgia 

and eastern Alabama. However, the contours 

would be less smooth and regular if more subsurface 

data were available. Published geological maps of 

Alabama and Georgia show that faults in the rocks of 

the Piedmont pass under the sedimentary rocks of 

the Coastal Plain. Temple Exploration Company's 

Smith Lumber Company well No. 1 (sec. 26, T. 8 N., 

R. 16 E.), Crenshaw County, Ala., was abandoned 

at the total depth of 10, 830 feet before it reached the 

"basement" rocks. Hard red micaceous shale· 

encountered in the bottom part of the hole is lithologically similar to Triassic rocks outcropping at 

many localities. The subsea elevation at the bottom 

of the Smith Lumber Company well when compared 

with the subsea elevation at the top of the crystalline 

rocks in Capital Oil & Gas Company's Gholston well, 

Bullock County, shows that in east-central Alabama 

the surface of the crystalline rocks slopes south, 

apparently at the rate of more than 250 feet per mile. 

In west-central Alabama, the rate of slope of the 

surface of the buried pre-~~sozoic rocks is approximately 70-80 feet per mile toward the southwest. 

Lower Cretaceous clastic beds overlie qneiss . in Capital Oil & Gas Company's Gholston well No. 1 

(sec. 18, T. 14 N., R. 22 E.) and Pickett well No. 1 

(sec. 22, T. 13 N., R. 21 E.), .Bullock County, Ala. 

Lower Cretaceous or older Mesozoic rocks overlie 

Kind of Depth of Total depth . rock penetration of well 

(Feet) (Feet) 

1 Capital 0. & G. Co. Diorite qneiss 8 1, 706 

Gholston No. 1 

Bullock County, 'Ala. 

4 Seaboard Oil Co. Granite qneiss .262 5, 780 

McConnico No. 1 

Wilcox-County, Ala. 

9 Tricon Minerals, Ip.c. Biotite gneiss 4 1,494 

Duke No. 1 

Houston County, Ga. 

10 Tricon Minerals, Inc. Biotite gneiss 13 1,698 

Gilbert No. 1 

Houston County, Ga:. 

12 W. B. Hinton Granite? 7 4,355 

Adams-McCaskill No. 1 

- •· :I=>ie!~~ 9~mnty, Ga. -- ----

-: 5-
-1,000-

-2,000-

-3,000-

-4,000-

-5,000-

-6,000-

-7,000-

-8,000-

-9,000-

-10,000-

-11,000-

-12,000-

-13,000-

-14,000-

-15,000-

17 86 88 84 27 

G \ ROCKS NOT 

\ DIFFERENTIATED 

',?) 

' '-, D 

.......... 

'?.._ B L. CRET. ---?-----"", v 

' '? 

p 

EXPLANATION OF LETTER SYMBOLS 

TRIASSIC (?) ROCKS 

D-Diabase 

8-Basalt 

PRE-MESOZOIC ROCKS 

P- Paleozoic strata 

v- Rhyolite, tuff, and agglomerate 

G-Granite 

Section along line A-A' of figures and 2. 

ARCH 

37 66 23 

Numbers above wells correspond to those on figures and 2, and in tables 1-5. 

Oi;;;;;;;;;;;;;;:;;;;;;;;;;;ii2il:5===5::ti0~;;;;;;:;;;;;;;;;;i:i75====::3100 MILES 

Figure 3.--North-south structural cross section from outcrop of crystalline rocks in central 

Georgia to Big Pine Key, Monroe County, Fla. Section along line A-A' (fig. 1) 
SOUTH FLORIDA EMBAYMENT 

5 22 20 21 94 97 96 

A' 

-==~===::---,-----,------.-------,---_;_--,-----------"""?""rSea level 

POST-EOCENE 

~-+---------~ -1,000 
granite gneiss in Seaboard Oil Company's McConnico 

well No. 1 (sec. 32, T. 12 N., R. 10· E.) in Wilcox 

County, Ala. The middle member of the early Upper 

Cretaceous Atkinson formation (Applin and Applin, 1947, 

figs. 1 and 2, and text) overlies granite in W. B. 

Hinton's Adams-McCaskill well No. 1 (Lot 332, Land 

District 4) and Pan American Production Company's 

Adams-McCaskill well No. 1 (Lot 329, Land District 

Well Name of well 

No. 

5 Oil Development Co. of 

of Fla .. Arnold No. 1 

Lake County,. Fla. 

6 Humble 0. & R. Co. 

Carroll No. 1 

Osceola County, Fla: 

4), Pierce County, Ga. The beds overlying the crystalline rocks in the northern part of the Georgia 

Coastal Plain were not differentiated for purposes of 

this report. 

Determinations of the crystalfine rocks encountered in three wells in the central part of peninsular 

Flqrida are shown in table 1 and in the following list: 

Kind of Depth of Total dept h 

rock penetration of well 

(Feet) (Feet) 

Granite 17 6,120 

Granite 14 8,049 

7 Sun Oil Co. Hornblende 48 5,958 

Powell Land Co. No. 1 

Volusia County, Fla. 

The writer's interpretation of the area occupied by the 

crystalline rocks in Florida is shown diagrammatically 

on the map {fig. 1). The age of the rocks has not been 

definitely determined, but alternative suggestions are 

presented that they are: a part of the pre~Cambrian 

basement complex; or Paleozoic in age. 

Rhyolitic lavas and pyroclastic ·rocks. 

Eight wells in the central part of peninsular 

Florida and two wells in southeastern Georgia terminated in volcanic rocks that for the most part are 

rhyolitic lavas, tuffs, arid agglomerates (table 2 and 

fig. 1) . Basalt occtirred in two wells in association 

with rhyolite and tuff.· Petrographic determinations oi 

the volcanic rocks in the 10 wells are shown in table 2 

and in the list shown on page· 9. 

The underground areal extent of sedimentary 

·strata can be mapped with reasonable accuracy 'from 

data supplied by well samples. Igneous bodies, on the contrary, are discontinuous and when concealed 

their size and shape must be inferred from independent 

sources (Moody, 1949, p. 1414). In the diagrammatic 

representation (fig. 1) of the subsurface distribution 

of the rhyolitic lavas and pyroclastic rocks, the 

factors considered are as follows: 

1. The geographic locations of the wells {fig. 1) 

roughly outline the areas within which the volcanic 

rocks occur. 

2. The kinds of rocks encountered in the 

different wells are indicative of their extrusive origin. 

Samples of rhyolite show· flow structure, and no 

positive evidence points to an intrusive origin for ~y 

·of these rocks. The rocks occur possibly as a 

continuous body of tuffs and lava flows; or pp_ssibly 

they form a zone of more or less localized discontinuous bodies separated from each other by intervening 

sedimentary formations. 

diorite 

Florida strongly suggests that they underlie the 

greater part of the area mapped diagrammatically 

in-figure 1. Humble Oil & Refining Company's 

Carlton well No. 1 (sec. 31, T. 38 S., R. 29 E.), 

Highlands County, is the southernmost occurrence 

of the volcanic rocks. Other wells in the southern 

part of the State were not drilled sufficiently deep to 

reach the stratigraphic position of the volcanics. 

The wells in Florida and Georgia did not 

penetrate the formations underlying the rhyolitic 

rocks. Lower C::retaceous clastic rocks unconformably 

overlie the volcanics in nine wells, and iii one well, 

Sun Oil Company's Camp No. 1 (sec. 16, T. 16 S., · R. 23 E.), Marion County, Fla.,. volcanic agglomerate 

is overlain by unfossiliferous sedimentary rocks that 

are lithologically correlated with Paleozoic strata. 

Cross section A-A' (fig. 3) begins at the gutcrop 

of the crystalline rocks in Georgia and extends southward through wells in the Coastal 'Plain of Georgia and 

peninsular Florida as far as Big Pine Key, Monroe 

County. Number 23 on cross section A-A' .is a graphic 

log of the Camp No. 1 which shows the relation of the 

agglomerate to the Pal~ozoic strata. In the Camp well, 

the volcanic rocks encountered at the depth of 4615 

feet are overlain by· arkosic conglomerate which, in 

turn, is over lain by approximately 350 feet of quartzitic sandstone. The quartzitic sandstone in the Camp 

well is lithologically similar to sandstone encountered 

in other wells in Florida that contliins fossils icfentified 

as Paleozoic species. A core of the conglomerate 

taken at the depth of 5474-5484 feet contains two kinds 

"of material in the core, one of which is a fine-grained 

sediment that is possibly volcanic ash; the other; a 

coarse arkose composed of rounded pebbles of quartz 

and potassic feldspar. 

A series of deep wells on the south flank of the. 

3. The, upiform southward.gradient (fig. 2) of the 

surface of tlie volcanic rocks in central peninsular _ 8 _ 

Peninsular arch (cross section A-A', fig. 3) encountered 

a basal sand occurring unconformably above the volcanic 

and crystall~e rocks and underlying nonclasti.c Lower 

Cretaceo~ Comanche be<;ls. The layers of pdorly sorted, fme to co;3.rse sand, siltstone, and red and green 
Well Name of well Kind of Depth of Total depth 

No". rock penetration of well 

(Feet) (Feet) 

19 Humble 0. & R. Co. Tuff and volcanic ag- 44 ·4,632 

Campbell No. 1 glomerate of rhyoFlagler County, Fla. litic composition. 

20 Humble 0. & R. Co. Lavas and pyroclastic 108 11,934 

Keen No. 1 rocks 

Hardee County, Fla. 

21 Humble 0. & R. Co. Basalt, rhyolite por- 367 12,985 

Carlton No. 1 phyry, and related 

Highlands County, Fla. kinds of volcanic rocl,s:s. 

22 Humble 0. & R. Co. Rhyolite and·volcanic 119 10, 129 

Jameson No: 1 agglomerate 

Hillsborough County, 

Fla. 

23 Sun Oil Company Volcanic agglomerate 22 4,837 

Camp No. 1 or tuff of rhyolitic 

Marion County, Fla. composition 

24 Humble 0 .. & R. Co. Rhyolite 58 8,798 

Hayman No. 1 

Osceola County, Fla. 

25 Sun Oil Co. Volcanic ash a:nd tuff. 19 3, 892 

Westbury No. 1 

Putnam County, Fla. 

28 Grace Drilling Co. Rhyolitic ? volcanic 21 5,424 

Retail Lumber Co. , rock 

No. 1 

Volusia County, Fla. 

27 Sun Oil Company Volcanic tuff or 78 4,298 

Doster-Ladson No. 1 agglomerate of rhyoAtkinson County,. Ga. litic composition. 

28 The California Co. Volcanic ash and 281 4, 955 

Buie No. 1 rhyolitic tuff. 

Camden County, Ga. 

shale comprising the basal sand merge laterally 

southward into the series of limestone; dolomite, and 

anhydrite that compose the Comanche rocks in the 

deeper part of the South Florida basin. Using microfaunal and lithologic studies of well samples, geologists have differentiated the Comanche limestones 

and dolomites of southern Florida into three stratigraphic units that are of Trinity, Fredericksburg, and 

Washita age, respectiyely. The cross section shows 

three wells drilled by Humble Oil & Refining Co. that 

encountered the basal sand below nonelastic beds of 

Trinity age. The wells are the Carlton we~l No. 1 

(sec. 34, T. 38 S., R. 29 E.), Highlands County; 

Keen well No. 1 (sec. 23, T. 35 S., R. 23 E.), Hardee 

County; and Jameson well No. 1 (sec. 7, T. 31 S., 

R. 22 E.), Hillsborough County. In Oil Development 

Company of Florida's Arnold ·well No. 1 (sec. 17,. 

T. 24 S., R. 25 E.), Lake County, the basal sand 

underlies limestone and dolomite of Fredericksburg 

age. One hundred and eighteen feet of argillaceous 

sandstone overlying Paleozoic strata in Sun Oil 

Company's Camp well No. 1, is classified as Washita 

or possibly Fredericksburg in age. The beds of 

Trinity age in the basinward wells pinch out against 

the southward sloping surface of the volcanic rocks. 

The up-dip wells show that, by series of overlaps, 

the progressively younger beds of Fredericksburg 

and Washita age transgress northward and, in turn, 

pinch out against the older rocks. 

Humble Oil· & Refining Company's Jameson 

well No. 1, Hillsborough County, Fla., at a depth 

of 10,010 feet, cored the contact of the Lower Cretaceous basal sand with the underlying volcanic rocks. 

The material in Core 122 at 9, 995-10,003 feet and 

in Core 123 at 10, 003-10, 010 feet was studied petrographically and Classified as an arkosic sediment. 

Core 124 at 10,010-10,019 feet was petrographically 

·determined as rhyolite. Prof. Frank F. Grout, 

Visiting Professor of Geology at Florida State 

University, Tallahassee, studied a thin section of 

Core 124. His report states that flow structure in the 

rhyolite is shown by the arrangement of mineral 

grains in elongated parallel streaks that bend.around 

phenocrysts; Prof. Grout also stated his opinion 

that the arkose in Core 122 and Core 123 could be 

derived from rhyolite. 
54 

B 

83 81 56 

PENINSULAR 

58 55 69 45 

ARCH 

40 41 19 

B' 

Sea level~----------~-----r-----.-----.--~--r-----~--------r-----------~---------------.- Sea level 

-1000 

-2000 

-3000 

-4000 

-5000 

-6000 

-7000 

EOCENE AND 

UPPER 

LOWER 

CRETACEOUS 

0 

POST- OCENE 

·cRETACEOUS 

EXPLANATION OF LETTER SYMBOLS 

TRIASSIC (?) ROCKS 

B- Basalt 

D- Diabase 

PRE-MESOZOIC ROCKS 

P- Paleozoic strata 

V- Rhyolitic tuff and agglomerate 

Section along line 8-B' of figures I and 2. 

Numbers above wells correspond to those 

on figures I and 2. and in tables 1-4. 

25 50 75 100 MILES 

Figure 4.--West-east structural cross section from Jefferson County to Flagler County, Fla. 

Section along line B-B' (fig. 1) 

-1000 

-2000 

-3000 

-4000 

-5000 

- -6000 

- -1000 
Several wells in Florida encountered thin layers 

of volcanic ash and bentonite interbedded in the Upper 

and Lower Cretaceous strata, but none of the wells 

penetrated tuffs, a,gglomerates, or lavas within the 

Cretaceous or younger formations. Conversely, in 

the Gulf Coastal Plain farther north, lavas, pyroclastic 

rocks, and tuffaceous sandstones are interbedded in 

early and middle Upper Cretaceous formations. 

Moody (1949, pp. 1427-1428) has pointed out that 

data from deep wells in the northern Gulf Coastal 

Plain "verify and recapitulate the ideas and conclusions 

drawn from field observations made by earlier workers 

in Coastal Plain igneous geology." He presents data 

to show that "magma invaded the northern Gulf Coastal 

Plain during successive time intervals in the Mesozoic 

era; the first invasion may have transpired as early 

as the Triassic period; the last was niid- Upper 

Cretaceous in age." · 

The geologic setting of Florida is unique among 

areas of comparable size in the Gulf Coast. In the 

northern part of the peninsula, comparatively shallow 

oil test wells penetrate formations ranging in age 

from Recent to Paleozoic and possibly pre-Cambrian. 

Conclusions about the age and correlation of the buried 

igneous and metamorphic rocks of Florida depend, in 

part, on a comparative study of the Gulf Coast deposits 

in adjacent areas and, in part, on an understanding of 

rocks exposed ii?- the southern Appalachian Piedmont. 

Inforrtlation on the rocks of the Piedmont is, for the 

most part, fragmentary and controversial. However, 

in connection with estimates of the age of the rhyolite 

and pyroclastic rocks encountered in wells in Florida, 

it can be pointed out that published geologic maps of 

the Piedmont region show outcrops of volcanic rocks, 

the age of which has been variously regarded as preCambrian or Paleozoic. The Geologic Map of the 

United States (1Q33) classifies as pre-Cambrian 

("Algonkian?") a belt of metabasalt and aporhyolite 

that extends across North Carolina into southern 

Virginia. The Tectonic Map of the United States (1Q44) 

shows the Virgilina syncline and a number of other 

areas in the southeastern Piedmont in which Paleozoic(?) 

volcanics occur. The Geologic Map of North America 

(1946) shows a belt of npaleozoic volcanic slate" that 

extends northeastward from east-central Georgia 

"into southern Virginia. On the State Geologic Map 

of Georgia (1939), the slates, quartzites, and volcanics 

of the Little River series in the east-central part of 

the State are classified as, pre-Cambrian. King (1950, 

p. 657) discussed the significance of the somewhat 

metamorphosed sedimentary and volcanic rocks of the · 

Carolina slate belt in the southeast part of the Piedmont 

province. He pointed out that various suggestions have 

been made placinq the age of the "volcanic series" 

in a range from pre-Cambrian to Paleozoic. 

King (1949) described the base of the Cambrian 

in the southern Appalachians and discussed the geology 

of areas in northeast Tennessee and southwest Virginia 

in which tuffaceous deposits and lava flows are interbedded with early Paleozoic sedimentary rocks. The 

Unicoi formation, classified by King (1949, p. 521) 

as the basal formation of the Lower Cambrian Chilhowee 

group "contains flows-of amygdaloidal basalt and 

associated tuffaceous shales and sandstone. Great 

variations in the volcanics of the Unicoi may be observed 

both along the strike and between different outcrop 

belts. In places, two or more volcanic beds are present, each 100 feet or more thick; in others a single 

- 11-

thin bed is present; in others volcanic rocks are 

lacking." In the vicinity of Mt. Rogers, immediately 

north of the Virginia-Tennessee line, a body of 

dominantly rhyolitic volcanic rocks is classified by 

King (1949, p. 519) as the top of the pre-Cambrian 

Ocoee series in northeastern Tennessee. 

Data from additional de,~p wells are needed to 

establish definitely the stratigraphic position of the 

rhyolitic lavas and pyroclastic rocks encountered 

in wells in central Florida and southeastern Georgia. 

The full thickness of the extrusive rocks has not 

been penetrated, and well data do not reveal the nature 

of the underlying formations. As a working hypothesis 

in connection with the preparation of this report, the 

age of these volcanic rocks is tentatively classified 

as early Paleozoic or possibly pre-Cambrian; they are 

believed to be older than the Paleozoic strata of the 

Florida-Georgia area and are mapped as a unit, here 

interpreted as a continuous body of extrusive rocks 

or possibly a zone of closely related, localized beds. 

The factors that form the basis for this classification 

are summarized below: 

1. Sun on· Company's Camp well encountered 

volcanic agglomerate underlying deposits that are 

lithologically correlated with early Paleozoic strata 

in other wells in Florida; an arkosic conglomerate 

rests on the vqlcanic rocks and is possibly derived 

from them. 

2. The pre-Cretaceous age of the rhyolitic 

rocks in central Florida is shown by the series of 

overlaps in the Lower Cretaceous rocks that pinch 

out against the volcanics on the south flank of the 

Peninsular arch. Tuffs, agglomerates, and lavas have 

not beeri found in the Cretaceous and younqer formations 

in Florida. 

3. Geologic maps and reports relating to the 

southeastern Piedmont. region and the southern 

Appalachians show the widespread occurrence of 

early Paleozoic and pre-Cambrian volcanic rocks. 

The volcanic rocks lack indications of the effects 

of dynamic metamorphism, and consequently may be 

younger than pre-Cambrian. In this connection it 

is pointed out that the Paleozoic strata in the FloridaGeorgia area are horizontally bedded and unmetamor-. 

phosed. On the other hand, sills and flows of diabase 

and basalt which are discussed in ·subsequent pages 

of this report are classified, in part at least, as. the 

products of an early Mesozoic (Triassic?) periodi of 

volcanism that is unrelated to the rhyolitic rocks. 

These cut Paleozoic and Triassic(?) sediments and 

are therefore younger. On the contrary, the rhyolites 

are not known to cut or overlie th~se rocks, and are 

therefore presumably older. 

Paleozoic sedimentary rocks. 

Paleozoic sedimentary rocks (fig. 1) have been 

encountered in two geographically separate areas in 

the southeastern Coastal Plain. One area extends 

westward from west-central Alabama into Mississippi; 

the other occupies the north part of the Florida peninsula and an adjacent part of southeastern Georgia. The 

Paleozoic strata of the Florida-Georgia sector probably 

extends westward to southwest Georgia, southeast . 

Alabama, and the panhandle part of Florida where 
27 72 76 42 4643 45 37 66 23 5 22 20 21 

Present tta levei----"'---.....L.---"-----'-....._....._....___......._ I I I ____ .....L.--.~L------.....L.----_....---"'----------'-- CENOZO~C AND 

r11ent depth from 11a level 

to pelltplaned surface. 

3 

"' • 

~ 

~ CD 

~ 

Jl' "'N N "' "' '!- c, ·, 0 

! "'"'co 0 ~co_~ ~ 

"' t • 0 eft 

Q. ~ 

co N 

•• ., g. co • 0 

~ <~~_ 

·- ......._ 

----- 2 

------ 1 

PRE-MESOZOIC BASIN 

OR GRABEN 

\\ // \\ ______ ::/ , .. , 

1000 

EXPLANATION 

OJ SILURIAN AND ORDOVICIAN 

Sedim.entary roclll 

'----J.ill.--

r;;--1 PALEOZOIC (?) OR PRE-CAMBRIAN (?) 

~ Rhyolitic volcanic rockl 

r'i'1 PRE-CAMBRIAN (?) 

L!!....J Granite, diorite, and metamorphic rocks 

Nu....,. · tbovt wtHt correspond tt 

th ..... fiourea 1-1. and taltlte 1.-3. 

soo 

o'--------·--5.._0 _____ 1_,00 MILES 

Vertical acale repr11ent1 elevation above prettnt 

11a level ond below ~eneplaned aurface. 

Fioure 5 

DtAGRAMMATIC CROSS-SECTION ALONG PART OF LINE A-A' (FIGURES I AND 2) FROMA-TKINSON COUNTY, GEORGIA, ·TO HIGHLANDS COUNTY, FLORIDA, SHOWING A 

TENTATIVE INTERPRETATION OF THE STRUCTURE AT THE. £ND Of THE PALEOZOIC. 

MESOZOIC AOCKS 

PE~frPlAWED (?) SURFACE 

OF PRE~MJESOZOIC ROCKS 

Figure 5.-Diagrammatic cross secti_on along part of line A-A' (fig. 1) from Atkinson County, Ga., to Highlands County, Fla., showing 

an interpretation of the structure at the end of the Paleozoic era 
three wells encountered closely related Paleozoic rocks. 

On the one hand, the Paleozoic strata in Florida and 

Gebrgia are a clastic facies that ranges in age from 

late Cambrian or early Ordovician to Silurian. On the 

other hand, the buried Paleozoic rocks in west-central 

Alabama range in age from Cambrian and Ordovician 

to Pennsylvanian, the early and middle Paleozoic 

strata being chiefly nonelastic. 

West-central Alabama area. --The Paleozoic 

rocks'""'fThe subsurface in western Alabama represent, 

in general, the underground extension of the formations 

exposed in the southern Appalachians. In the southeastern part of the Black Warrior basin (Mellen, 1947) 

four wells encountered clastic rocks of Pennsylvanian 

age unconformably underlying sandstones and shales of 

the basal Upper Cretaceous Tuscaloosa group. The 

four wells and the oldest formation penetrated in each 

are shown in table 3 and in the following li~t: 

Well- Name of well Penetration Total depth Oldest formatio n 

into PaLeo- of well penetrated 

zoic strata (F~et) 

(Feet) 

31 Briggs and Knapp 1, 645 

Wefel No. 1 

Lamar County, Ala. 

32 De Soto 0. & G. Corp. 4,358 

Gardner No. 1 

Lamar County, Ala. 

33 Stanolind 0. & G. Co. 2,845 

Woods No. 1A 

Lamar County, Ala. 

35 C. H. Murphy, Jr. 4,553 

Oden-Eaton No. 1 

Pickens County, Ala. 

The folded and faulted rocks of the Appalachian 

Valley and Ridge province form the eastern boundary 

of the Black Warrior basin and plunge under the 

Coastal Plain deposits in central Alabama. Two wells 

(table 3 and fig. 1) in the Coastal Plain, Johnston and 

Hawkins' Willis well No. 1 (sec. 11, T. 20 N., R. 

1 E. ) , Greene County, and E. C. Johnston's Peteet 

well No. 1 (sec. 3, ·T. 16 N., ·R. 2 E.), Marengo 

County, are situated on the subsurface projection of 

the Valley and Ridge province. The middle and late 

Paleozoic rocks were not encountered in these wells, 

which entered a series of Ordovician limestones 

and dolomites directly below Lower Cretaceous or 

older Mesozoic rocks. This relationship is similar to 

that found on the outcrop in Bibb and Shelby Counties 

about 50 miles farther northeast. 

Florida-Georgia area. --The Paleozoic sedimentary rocks (fig. 1) m Florida and Georgia occupy 

an area roughly estimated at 25, 000 square miles on 

the highest part of the Peninsular arch. The southeastern limit of the area extends diagonally across the 

peninsula from a point between Jacksonville and 

St. Augustine on the east coast, to about the north 

end of Old Tampa Bay on the west coast; the northern 

limit is less definite but apparently extends across 

southern Georgia approximately parallel to the State 

line. Paleozoic strata (table 3 and fig. 1) were 

encountered in 37 wells in the north part of Florida; 

in 7 wells in the adjacent part of southern Georgia; 

and in a well in the southeast corner of Alabama. The 

rocks are chiefly quartzitic sandstones and dark shales, 

which for the most part are horizontally bedded and 

unmetamorphosed. A core from one of the wells 

s~owed a maximum inclination oi 20°-25°; and some 

-.13-

1,780 Limestone of 

Mississippian 

age. 

4,886 Highly siliceous 

limestone of 

Devonian or 

Silurian age. 

3,170 Limestone of 

Mississi}:pian 

age. 

5,503 Clastic rocks 

of Pennsylvanian age. 

geologists interpret the recrystallization of quartz 

grains seen in a few cores as evidence of incipient 

metamorphism. Cores and cuttings from scattered 

wells have yielded specimens of ostracods, conodonts 

and a number of megascopic fossils including species· 

of brachiopods, cephalopods, gastropods, pelecypods, 

graptolites, trilobites and eurypterids. Fragments 

of crinoid stems have been found in well samples and 

worm tubes occur in some sandstone cores. 

The Paleozoic sedimentary rocks in Florida 

and Georgia can be classified roughly on the basis of 

lateral lithologic variations. Near the southeastern 

limit of the area, half a dozen tests penetrated 

unfossiliferous, hard, white to light-tan micaceous 

feldspathic quartzitic sandstone containing occasional 

thin layers or irregular lenses of highly micaceous 

gray to greenish-gray shale and brick-red sandy 

shale. Two wells penetrated more than 2, 000 feet of 

the quartzitic sandstone. Ten wells that encountered 

black shale are located in a belt along the State line 

in southern Georgia and the northern part of Florida. 

The hard slaty black to gray micaceous carbonaceous 

fissile shale is irregularly interlensed with thin layers 

of siltstone and fine-grained sandstone. Nearly 1,.000 

·feet of black shale was penetrated in one well. A. 

possible third lithologic variety of the Paleozoic rocks 

is recognized in tests situated between the group.of 

wells that encountered the quartzitic sandstone and the 

ten wells encountering black shale. This variety consists 

of alternating layers of hard gray and white micaceous 

quartzitic sandstone and black, gray, and greenishgray shale. Classification is indefinite, as a rule,. in 

wells where the Paleozoic strata were pepetrated no 

more than a few feet. 
A vertical sequence has not been established for 

the different kinds of Paleozoic sedimentary rocks; 

and the groups of wells mentioned in the preceding 

paragraph are loosely segregated. For example, a 

number of wells in the "black shale beW' encountered 

quartzitic sandstone rather than shale. On the other 

hand, coastal Petroleum Company's Ragland well No. 1 

(sec. 16, T. 15 S., R. 13 E.), Levy County, Fla., 

on the west coast of the peninsula, penetrated 40 feet 

of black shale of Paleozoic age just above the bottom 

of the 5, 850-foot test; whereas, all other deep wells 

in this general area encountered quartzitic sandstone, 

and one of them, Stanolind Oil & Gas Company and 

Sun Oil Company's Perpetual Forest well No. 1 

(sec. 5, T. 11 S., R. 11 E.), Dixie County, Fla., 

penetrated 2, 282 feet of quartzitic sandstone between 

the depth of 5, 228 feet and the total depth of the test 

at 7, 510. 

The stratigraphic relations of the different kinds 

of Paleozoic sedimentary rocks in Florida and the 

significance of their lateral variations are problems 

con:fronting geologists engaged in subsurface mapping. 

Some geologists have suggested that the lithologic 

differences in the rocks are possibly explained by facies 

changes brought about by lateral variations in depositional conditions; others have pointed out that preMesozoic faulting may have brought into juxtaposition 

stratigraphic units having different lithology. The 

ultimate solution of the problem of the stratigraphy 

and pre-Mesozoic structure of the Paleozoic sedimentary rocks in Florida and Georgia awaits the 

drilling of deeper tests, and depends in large degree 

on lithologic and faunal studies now in progress that 

should eventually result in the differentiation of 

these rocks into stratigraphic units that are traceable 

from well to well. 

Little is known about the contact of the Paleozoic 

strata and the underlying rocks. Sun Oil Company's 

Camp No, 1, mentioned in foregoing paragraphs, 

encountered volcanic agglomerate below quartzitic 

sandstone of Paleozoic age. No other wells in the 

Florida-Georgia area. were drilled sufficiently deep 

to penetrate the rocks below the Paleozoic strata. 

A major unconformity marks the contact between 

the Paleozoic strata and the overlying Mesozoic 

deposits. In different parts of the Florida-Georgia 

area, beds that range in age from early Mesozoic to 

middle Late Cretaceous rest on the Paleozoic strata. 

Nonmarine deposits that are tentatively classified as 

Triassic or possibly Jurassic in age overlie Paleozoic 

sedimentary rocks in the northwest part of peninsular 

Florida. The early Mesozoic beds pinch out against 

the Paleozoic rocks on the west flank of the Peninsular 

arch and are overlapped by Lower Cretaceous clastic 

beds. Lower Cretaceous beds wedge out around an 

area of Paleozoic strata on the high part of the arch. 

The Lower Cretaceous wedge thickens rapidly on the 

west and south flanks of the arch but is relatively thin 

on the north and east. The early Upper Cretaceous 

Atkinson formation overlaps the Lower Cretaceous 

beds and pinches out, in turn, around a smaller "area" 

of Paleozoic strata. In two or three wells on the · 

crest of the arch, beds of Austin (middle Late 

Cretaceous) age rest' directly on the Paleozoic rocks. 

Numerous cores from wells on the Peninsular 

arch present physical evidence of the unconformity 

- 14-

between the early Paleozoic strata and Mesozoic rocks~ 

In the Paleozoic strata, dark shale or alternating beds 

of dark shale and sandstone grade gradually upward 

into a red zone, in which fossils have been found that 

are identical with those in the dark .beds below. The 

beds showing the gradational color change are 

considered by some geologists to be variants of the 

same stratigraphic unit, the red color being the result 

of weathering along the unconformity at the top of the 

early Paleozoic. A coarse conglomerate of quartzite 

pebbles occurs at the contact of the Paleozoic strata 

and the Lower Cretaceous. Well-rounded pebbles an 

inch or more in diameter have been recovered in cores, 

and drilling experience suggests the presence of larger 

pebbles Ol' boulders. 

Reports by other writers have referred to the 

Paleozoic sedimentary rocks encountered in wells in 

Florida and Georgia, and some of the reports have 

described species of Paleozoic fossils. The more 

important of these reports are here summarized. In 

regard to Ocala Oil Corporation's Clark-Ray-Johnson 

(York) well No. 1 (sec. 10, T. 16 S. , R. 20 E.), 

Marion County, Fla., Herman Gunter, State Geologist 

of Florida, reported (Gunter, 1928) "somewhere between 

the depths of 3, 970 and 4, 245 feet, the well passed · 

out of sedimentary formations and into metamorphic 

rocks. The cuttings within the interval mentioned 

consist of micaceous schist, slate and quartzite." 

Cooke and Mossom (1929, pp. 44-45) subsequently 

described an incomplete set of cuttings from the York 

well, classifying as "probably Paleozoic or older" 

the formations encountered between approximately 

4, 000 feet and the bottom of the test at 6, 180 feet. 

Campbell (1939, p. 95) suggested a long-range 

correlation between the rocks in the bottom part of the 

York well and lithologically similar rocks exposed 

in Cuba which other geologists had assigned to the San 

Cayetano (Upper Jurassic) formation. Applin and Applin 

(1944, p. 1723, figs. 13 and 22) did not assign a 

definite age to the rocks encountered in the York well 

below 4, 100 feet, or to lithologically similar rocks 

occurring below 3, 520 feet in J. S. Cosden's Lawson 

well No. 1 (sec. 25, T. 13 S., R. 20 E.), also in 

Marion County. They classified the age of these 

deposits as "Lower Cretaceous or older. " Cooke 

(1945, p. 21) designated as "probably of Paleozoic 

age" the rocks penetrated in the York well between 

4, 100 feet and 6, 180 feet, the total depth. In the 

present report, the quartzitic sandstone in the York 

and Lawson wells is classified as early Paleozoic. 

Between the depths of 4, 640 and 4, 808 feet, 

St. Mary''s River Oil Corporation's Hilliard Turpentine 

Co. well No. 1 (sec. 19, T. 4 N., R. 24 E.), Nassau 

County, Fla., encountered hard black noncalcareous 

shale which is interlensed with fine-grained quartzitic 

sandstone. The black shale overlies 13 feet of diabase 

at the bottom of the hole. The age of the black shale 

has been variously estimated. Campbell (November, 

1939) tentatively assigned "these rocks to the Mississippian be;cause of their similarity to the Chattanooga 

shales," and in this he was supported by R. S. Bassler 

of the United States National Museum. Schuchert 

(1943) di~cussed the occurrence of the black shale ·in 

the Hilliard well and questioned the Mississippian age 

determination. He thought the shale "more likely to be 

of Late Paleozoic (Pennsylvanian) age. " Cole (1944_, 

p. 32) has stated that in his opinion the rocks in question 

are Triassic in age and equivalent to the Newark series. 
Applin and Applin (1944, p. 1724) sugges~ed that the 

lithologic character of the black shale resembles 

Pennsylvanian or older rocks. Proof of the early 

Paleozoic age of the black shale in the Hilliard well 

was recently found by Jean Berdan, U. S. Geological 

Survey, who discovered a fragment of a eurypterid in 

the cuttings similar to and possibly identical with the 

form recently described by Kjellesvig - Waering (1950) 

from Sun Oil Company's Tillis No. 1 well, Suwannee 

C9unty, Fla. 

Howell and Richards (1949) described a species 

of brachiopod Lingulepis floridanus found in a core 

of fine-grained m1caceous sandstone taken at the 

depth of 3, 668-3, 671 feet in Sun Oil Company's 

Langston well No. 1 (sec. 8, T. 8 S., R. 14 E.) 

Dixie County, Fla. The authors assigned a late 

Cambrian or early Ordovician age to the species. 

Horace G. Richards (1948, p. 70) mentioned the 

occurrence of fossiliferous black shale in Coastal 

Petroleum Company's Ragland well No. 1 (sec. 16, 

T. · 15 S., R. 13 E.), Levy County, Fla., and quoted 

the opinion of G. Arthur Cooper, United States National 

Museum, that megascopic fossils discovered in the 

shale are probably of Devonian or Silurian age. 

F. M. Swartz (1949, p. 320) described and 

named Chevroleperditia chevronalis, a new genus and 

species of ostracod d1scovered in a core of black 

shale from the depth of 6, 965-6, 985 feet (6, 995-7, 015 

feet, corrected depth) in Mont Warren's Chandler 

well No. 1 (lot 406, Land District 26), Early County, 

Ga. Swartz stated that the species is suggestive of 

a late Ordovician or early Silurian age for the shale 

in which it was found. 

Erik N. Kjellesvig-Waering (1950) described 

and named a new species of Silurian eurypterid, 

Pterygotus floridanus, taken from a core at 3, 552 .. 

3, 568 feet m Sun 01l Company's Tillis well No. 1 

(sec. 28, T. 2 S., R. 15 E.), Suwannee County, Fla. 

TRIASSIC(?) DIABASE AND BASALT 

Diabase and basalt have been discovered in 18 

wells (table 4 and figs. 1 and 2) in the Coastal Plain 

of Alabama, Florida, and Georgia. Petrographic 

studies of well samples show that diabase -occurs in 

13 wells and basalt in three other wells, whereas two 

others encountered both diabase and basalt. The 

volcanic rocks occur as sills or dikes in some wells 

and presumably as flows in others. Four wells 

encountered diabase sills or dikes in clastic rocks of 

Triassic(?) age; four other wells encountered diabase 

and basalt sills in Paleozoic strata. Seven wells 

terminated in diabase and basalt underlying Lower 

Cretaceous or older·Mesozoic deposits. Three wells 

encountered diabase underlying Lower Cretaceous or 

older Mesozoic rocks and overlying Paleozoic strata. 

The tabulation that follows shows the distribution of 

the 18 wells on the basis of the different kinds of 

basaltic rocks encountered. 

Well Name of well Manner of 

occurrence Remarks 

79 

80 

54 

62 

63 

67 

81 

·W. B. Hinton et al 

Creel No. 1 

Barbour County, Ala. 

H. A. Stebinger 

Robertson No. 1 

Barbour County, Ala. 

Coastal Petroleum Co. 

Larsh No. 1 

Jefferson County, Fla. 

Hunt Oil Co. 

Gibson No. 2 

Madison County, Fla. 

Hunt Oil Co. 

Gibson No. 4 

Madison Coimty, Fla. 

St. Mary's River Oil Corp. 

Hilliard Turpentine Co. No. 1 

Nassau County, Fla. 

Gulf Oil Corp. 

Brooks-Scanlon Block 33 

well No. 1 

Taylor County, Fla. 

Sill or dikes 

Sills or dike 

Sills or dike 

Flow? or sill 

Flow? or sill 

Sill or dike 

Well terminated in 

diabase gabbro 

- 15-

In clastic rocks 

of Triassic(?) age. 

In clastic rocks 

of Triassic(?) age. 

In clastic rocks 

of Triassic(?) age. 

Underlies Lower Cretaceous or older 

Mesozoic clastic rocks; 

overl.ies black shale of Paleozoic age. 

Underlies Lower Cretaceous or older 

Mesozoic clastic rocks; 

overlies sandstone and shale of 

Paleozoic age. 

Underlies black shale of Paleozoic 

age. 

Underlies early Mesozoic clastic 

rocks 

Continued on page 16 
Continued: 

Well Name of well Manner of 

occurrence 

Remarks 

Diabase (Continued) 

82 Gulf Oil Corp. 

Brooks-Scanlon Block 42 

well No. l 

Flow? Well terminated Underlies early Mesozoic clastic rocks. 

in diabase 

Taylor County, Fla. 

85 Sowega Minerals Exploration Well terminated in 

Co. diabase 

West No. l 

Calhoun County, Ga. 

74 Humble 0. & R. Co. Sill or dike 

Bennett and Langsdale No. l 

Echols County, Ga. 

86 Calaphor Manufacturing Co. Well terminated in 

McCain No. l diabase 

Laurens County, Ga. 

87 Stanolind 0. & G. Co. Sills or dike 

Pullen No. l 

Mitchell County, Ga. 

88 J. E. Weatherford Well terminated in 

Wilkes No. l diabase 

Montgomery County, Ga. 

Underlies early Mesozoic clastic rocks. 

In Paleozoic strata. 

Underlies Lower Cretaceous or older Mesozoic rocks. 

In clastic rocks of Triassic(?) age. 

Underlies Lower Cretaceous or older 

Mesozoic rocks. 

Basalt 

53 Humble 0. & R. Co. 

60 

Tindel No. l 

Jackson County, Fla. 

Humble 0. & R. Co. 

Robinson No. l 

Levy County, Fla. 

Sills or dike In Paleozoic strata. 

Flow? See data on well in table 4. 

84 Felsenthal and Weatherford 

Bradley No. l 

Flow? Well terminated 

in basalt 

Underlies Lower Cretaceous or older 

Mesozoic rocks. 

Appling County, Ga. 

Diabase and basalt 

42 Humble 0. & R. Co. Sills or dike In Paleozoic strata. 

Cone No. l 

Columbia County, Fla. 

83 Humble 0. & R. Co. Well terminated in dia- Underlies early Mesozoic c~ast·ic rocks. 

Hodges No. l base gabbro See data on well in table 4. 

Taylor County, Fla. 

The time of emplacement of the diabase and 

basalt has not been definitely established. Indications of volcanism are lacking in the Cretaceous 

and younger formations of the southeastern region, 

but evidence points to the early Mesozoic age of the 

diabase in a part of the wells listed in the foregoing 

tabulation. Four wells encountered diabase sills or 

dikes in clastic beds that are tentatively classified as 

Triassic in age. Cores and cuttings show that the 

strata are chiefly hard red micaceous shale and 

poorly sorted fine- to coarse-grained sandstone which 

are lithologically similar to Triassic shales and 

sandstones exposed in the southeastern Piedmont 

16 

Two wells in east-central Alabama encountered 

diabase sills in Triassic ( ?) strata composed 

of highly arkosic sandstones, beds of volcanic ash 

and conglomerates. The conglomerates contain debris 

that suggests rapid erosion from nearby outcrops of 

basement rocks. Petrographic studies show that the 

diabase in the wells in the southeastern region is 

mineralogically similar to Triassic diabase exposed 

at many localities along the Atlantic seaboard. The 

diabase dikes in the Piedmont province in Georgia 

have been tentatively classified as Triassic, and one 

of the dikes is overlapped unconformably by the Coastal 

Plain deposits (Moody, 1949, p. 1411). 
Additional subsurface data are needed to determine the age of the diabase and basalt sills or dikes 

that intruded the Paleozoic strata. The mineral 

composition of the diabase in the Hilliard well, Nassau 

County, Fla. , has been compared to Triassic diabase. 

Cole (1944, pp. 89-94)quotes J. Osborne Fuller in 

regard to the diabase in the Hilliard well as follows: 11 The diabase in the Florida sample agrees surprisingly 

well in mineral composition with the upper chilled 

zone of the Palisade diabase. The sample from the 

F!orida well is tentatively classified as Triassic in 

age. 11 

PRE-MESOZOIC STRUCTURE 

OF THE FLORIDA PENINSULA 

During the past 10 years, a quantity of new 

information has been accumulated regarding the areal 

distribution, lithology, and fauna of the different kinds 

of rocks that underlie the Coastal Plain deposits in 

Florida and adjacent part of south Georgia. In a report 

on the tectonic framework of the southeastern States, 

King (1950, pp. 657-658) discussed the general 

relations between the exposed rocks in the Appalachian 

Highlands and the unmetamorphosed and little-folded 

Paleozoic rocks of Florida. Nevertheless, information is lacking on. important details of the stratigraphy 

and pre-Mesozoic structure of these buried rocks. 

Data from the scattered wells have not established the 

stratigraphic sequence of the different kinds of preMesozoic.rocks, and their complex structure is subject 

to a variety of interpretations. As a working hypothesis 

that may serve as a basis for future investigations, •the. 

writer offers his interpretation of the pre-Mesozoic 

geology of the rocks that form the core of the Florida 

peninsula. In connection with the map (fig. 1) showing 

the areal distribution of the rocks, a diagrammatic 

cross section {fig. 5) drawn through some of the deep 

wells in south Georgia and peninsular Florida portrays 

graphically this tentative interpretation of the stratigraphy and structure of the early Paleozoic and preCambrian(?) rocks. 

Figure 5 shows a regionally high area in the 

pre-Cambrian(?) crystalline rocks of central Florida, 

bordering on the south a basin or graben situated in 

the northern part of the peninsula. A thickness of 

more than 2, 000 feet of Ordovician and Silurian strata 

occupies the downwarp, the axis of which trends 

northeastward approximately at right angles to the 

axis of the peninsula. The subsurface data are not 

sufficient.to classify the downwarped feature definitely, 

and alternative possibilities are pointed out. On the 

one hand, the lateral lithologic variations of the 

Paleozoic strata discussed in preceeding paragraphs 

suggest deposition of the sediments in a progressively 

subsiding basin. On the other hand, the thickness of 

more than 2, 000 feet of quartzitic sandstone encountered 

in wells near the southeastern limit of the area suggest 

entrapment of a segment of the early Paleozoic strata in 

a graben or series of blocks that were downfaulted by 

post-Silurian tectonic movements. In either case, the 

sheltered position of the strata preserved them from 

destruction during the period of erosion that followed 

the Silurian deposition. 

The Florida peninsula was apparently an area of 

nondeposition during post-Silurian Paleozoic time. 

Erosion and possibly peneplanation exposed on the 

land surface the pattern (fig. 1) of pre-Cambrian(?} 

and early Paleozoic rocks revealed by well cores. 

Subsequently, regional movements during the Mesozoic 

and Cenozoic were instrumental in shaping the present 

configuration of the Peninsular arch (figs. 2, 3, and 4) 

and the South Florida basin. 

REFERENCES 

Applin, , P. L. and Applin, E. R., 1944, Regional subsurface stratigraphy and structure of Florida and southern 

Georgia: Am. Assoc. Petroleum Geologists Bull., vol. 28, no. 12, pp. 1673-1753. 

Applin, P. L. and Applin, E. R., 1947, Regional subsurface stratigraphy, structure and correlation of middle and 

early Upper Cretaceous rocks in Alabama, Georgia, and north Florida: U. S. Geol. Survey Oil and Gas Inv. 

Prelim. Chart 26. 

Campbell, R. B., Paleozoic under Florida?: Am. Assoc. Petroleum Geologists Bull., vol. 23, no. 11, pp. 1712-

1713, November 1939. 

---...,...,.,........,.. ....... -- Outline of the geological history of peninsular Florida: Florida Acad. Sci. Proc. , vol. 4, 

pp. 87-105. 

Carsey, J. B., Geology of the Gulf coastal area and continental shelf: Am Assoc. Petroleum Geplogists Bt~ll., 

vol. 34, no. 3, pp. 361-385, March 1950. 

Cole, W. S., Stratigraphic and paleontologic studies of wells in Florida- No. 3: Florida Geoi. Survey Bull. 26, 1944. 

Cooke, C. W., Geology of Florida: Florida Geol. Survey Bull. 29, 1945. 

Cooke, C. w., and Mossom, Stuart, The geology of Florida: Florida Geol. Survey 20th Ann. Rept., 1927-1928, 

pp. 29-227, 1929. 

Gunter, Herman, Basement rocks encountered in a well in Florida: Am. Assoc. Petroleum Geologists Bull., 

vol. 12, no. 11, pp. 1107-1108, November 1928. 

Howell, B. F. and Richards, H •. G. , New Paleozoic linguloid brachipod from Florida: Wagner Free !I;lst. Sci. Bull. , 

vol. 24, no .. 4, pp. 35-37, November 1949. _ 17-
King, P. B., The base of the Cambrian in the southern Appalachians (in two parts): Part I, Am. Jour. Sci., 

vol. 247, pp. 513-530, August 194-9; Part II, Am. Jour. Sci. vol. 247, pp. 622-645, September 1949. 

Tectonic framework of southeastern United States: Am. Assoc. Petroleum Geologists Bull., vol. 34, 

no. 4, pp. 635-671, April 1950. 

Kjellesvig-Waering, E. N.·, A new Silurian eurypterid from Florida: Jour. Paleontology, vol. 24, no. 2, pp. 229-

231, March 1950. 

Mellen, F. F., Black Warrior basin, Alabama and Mississippi: Am. Assoc. Petroleum Geologists Bull., vol. 31, · no. 10, pp. 1801-1816, October 1947. 

Moody, C. L., Mesozoic igneous rocks of northern Gulf Coastal Plain: Am. Assoc. Petroleum Geologists Bull., 

vol. 33, no. 8, pp. 1410-1428, August 1949. 

Mossom, Stuart, A review of the structure and stratigraphy of Florida: Florida Geol. Survey 17th Ann. Rept. 

1924-1925, pp. 174-275, 1926. 

Pressler, E. D., Geology and occurrence of oil in Florida: Am. Assoc. Petroleum Geologists Bull., vol. 31, 

no. 10, pp. 1851-1862, October 1947. 

Richards, H. G., Studies on the subsurface geology and paleontology of the Atlantic Coastal Plain: Philadelphia 

Acad. Nat. Sci. Proc., vol. C, pp. 39-76, 1948. 

Schuchert, Charles, Stratigraphy of the eastern and central United States, pp. 453-456, John Wiley and Sons, 1943. 

Swartz, F. M. , Muscle marks, hinge and overlap features, and classification of some Leperditiidae: Jour. 

Paleontology, vol. 23, no. 3, pp. 306-327, May 1949. 

Vernon, R. 0., Ma."'luscript, in preparation, on the geology of Citrus and Levy Counties, Fla., (1950) 

- 18-
Well 

No. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

ll 

12 

13 

14 

15 

Bullock 

Bullock 

Montgomery 

Wilcox 

Lake 

Osceola 

Volusia 

Burke 

Houston 

Houston 

Jefferson 

Pierce 

Pierce 

Richmond 

Richmond 

Name and location of well 

Capital Oil & Gas Co. 5-22-1945 300 

Mrs. Ethel B. Gholston No. 1 

Sec. 18, T. 14 N., R. 22 E. 

Capital Oil & Gas Co. 

Fred Pickett No.1 

6-13-1945 430 

Sec. 22, T. 13 N., R. 21 E. 

Montgomery Oil Co. 

Snowdoun No. 1 

1923 222 

Sec. 29 or 30, T. 15 N., R. 18 E. 

Seaboard Oil Co. 12-ll-1945 186 

S. M. McConnico No. 1 

Sec. 32, T. 12 N., R. 10 E. 

Oil Development Co. of Florida 1937 120 

J. Ray Arnold No. 1 

Sec. 17, T. 24 S., R. 25 E. 

Humble Oil & Refining Co. 7-15-l946 62 

N. Ray Carroll No. 1 

Sec. 10, T. 27 S., R. 34 E. 

Sun 011 Co. 9-14-1946 48 

Powell Land Company No. 1 

Sec. ll T. 17 S. R. 31 E. 

Three Creeks Oil Co. well 1923 

2.5 miles east of Green Cut. 

Tricon Minerals, Inc. 9- 7-1949 419 

J. D. Duke No. 1 

Lot 44, Land District 14 

Tricon Minerals, Inc. 9-25-1949 367 

H. B. Gilbert No. 1 

Lot 266, Land District 13 

A. F. Lucas and Georgia 1907 

Petroleum Oil Co. well 

3.5 miles southwest of Louisville, Ga. 

w. B. Hinton 5- 7-1939 75 

Adams-McCaskill No. 1 

Lot 332, Land District 4 

Pan-American Production Co. 5-13-1938 75 

Adams-McCaskill No. 1 

Lot 329, Land District 4 

Water well at Georgia Training 136 

School, Gracewood, Ga. 

Water well at Circular Court, 

6.5 miles south of Augusta, Ga. 156 

, Type of crystalline 

rock 

AJabama 

*Diorite gneiss 

Metamorphic rock, prooably gneiss 

Crystalline rock? 

*Granite gneiss 

Florida 

Granite 

rAlte""' biotite granite and veined 

j*Hornblende diorite 

Georgl.a 

Crystalline rock 

Biotite gneiss 

Biotite gneiss 

In crystalline rock at total depth 

**Granite 

Granite 

Talcose schist 

Talcose schist 

19 

1698 

2495 

1895 

5518 

6103 

8o35 

5910 

1002 

1490 

1685 

4348 

4345 

325 

175 

Elevation at top of 

crystalline rock 

-1398 

-2o65 

-1673 

-5332 

-5983 

-7973 

-IJ862 

-1071 

-1318 

-4273 

-4270 - 189 - 19 

Remarks 

8 17o6 

28 2523 No cores taken in crys- talline rock; determination from Geol. Survey of Alabama Bull. 57, 

p. 22, 1945. 

12 2007 Data from Geol. Survey of Alabama Bull. 50, 

pp. 158-159, 1941. 

262 5780 

17 6120 Not studied petro- graphically. 

14 8049 

48 5958 

31 1033 Data from Am. Assoc. 

Petroleum Geologists Bull. Vol. 29, no. 7, 

p. 926, July 1945. 

4 1494 

13 1698 

1143 Data from Geol. Survey 

of Geor~a Bull. 40, 

pp. 56- , 1923. 

7 4355 

31 4376 Not studied petro- graphically 

875 1200 Data from Am. Assoc. 

Petroleum Geologists Bull. 

vol. 294 no.·7, p. 925, 

July 19 5 

154 329 Data from Am. Assoc. 

Petroleum Geologists Bull. 

vol. 294 no. 7, p. 925, 

July 19 5 
Well 

No. 

16 

17 

18 

Richmond 

Washington 

Washington 

Taltle 1. Oat. • -11a ,...,..,,.,-,_,., .,,_,. _, _,.,.fc rocb fn Maha.,., Flodda, ond Geor,fa Coastal Plafn··Continued. 

Name and location of well 

Three Creeks Oil Co. well 1921 

Allen's Station, 9 miles south 

of Augusta, Ga. 

Layne-Atlantic's N: S. C. water 1945 46o 

well 

2 miles southwest of Tennile, Ga. 

Middle Georgia Oil & Gas Co. 

well, 12 miles northwest of 19~ 

Sandersville, Ga. 

. TJpe of ~:I:.talline 

Georgia--Continued. 

In crystalline rock at total depth 

Gran1te 871 

In crystalline rock at total- depth 

Elevation at top of - crystalline rock 

-4ll 

Penetration 

of crystalline 

rock (feet) 

l 

approx. 

I 

Remarks 

·' 400 Data from Am. Assoc. 

Petroleum Geologists 

Bull2l; vol. 29, no. 7, 

p. 9 , July 1945 

872 Data from oil company- scouts 

400 Data from Am. Assoc. 

Petroleum Geologists 

Bull2l; vol. 29, no. 7; 

p. 9 , July 1945 
Well 

No. 

19 

20 

21 

22 

23 

. 24 

25 

26 

27. 

28 

Flagler 

Hardee 

. I 

Tallie 2. Dolo • wells,...,.., ..,.,ltic '--· ,.,_ ..J .,.,_. ,_ car1N1 FloriJo _, • ....,,._., C.orvla. 

(Tho -11• h-llolod •• oho- In fig-• 1 •d 2 and ooooo of th.., are oho- on aeoo -·A • A' _. B • B'. Tile-. of ...... no., ... -_. -•• ooctl•o ...... _.to than In thlo table. El..,.,tlono and doptho oxpreoood In loot, datum oo .. lo ... l • 

._. --· br a-1• Ml'- IL 5. Goelogial S....,..) 

Name and location of well 

Humble Oil & Refining Co. 2-26-1947 

J. W. Campbell No. 1 

Sec. 8, T. 11 S., R. 28 E. 

Humble Oil & Ref1n1ng Co. i-12-1948 

B. T. Keen No. 1 

Sec. 23, T. 35 S., R •.. 23 E~ 

'1 

a, 

T)pe of volcanic 

rock 

Plorlda 

Tuf'f' and volcanic 

aggl.aaere.te of, 

rb;Jolltic CCIIIP)-

s1tion. 

Le.v8 and ~last1c rocks: .. . .. '. . 

JJ.588. 

~,. 

-~1.82!3 

Sub-sea 

elevation at top of volcanl.c rock 

- 4,557 

-1,~,745 

Depth of pene-

'tration into 

volcanic· 

rock 

44 

i06 

Remarks 

4,632 "Mixed "'tuff derived .fl"OID 

an igneous complex.. 

Ori~· sedimentaey or exp osive igneous action." 

F. F. Grout. . · 

11,9~ 

Highlands Humble 011 & Ref1n1ng Co. -1-17-19-'Hi 114 .ADQ"p!oidal baSe.l.t, 12.618 -12.504 ~7 12,985 Southernmost occ~nce G. C. Carlton Estate No. 1 of igneous rocks in :rallte po~ and Sec. ~. T. ,S S., R, 29 E. ated kinds of Florida. 

volcanic. rocks. 

Hillsb:>- Humble Oil & Refining Co. 7- 6.;,19116 . 112 Rb;Jollte. and volcanic 10.010 - 9.898 119 10,129 

rough' T. S. Jameson No. 1 aggl.ame~te Sec. 7, T. 31 S. , R. 22 E. 

Marion Sun Q11 Co. 5-20-1947 74'.' Vol~c '-e.ggl~rate 4,615 - 4,541 22 4,637 "Mixed tuff derived from 

Henry N. Camp No. 1 '. or tutr or rhyolitic an igneous complex" 

Sec. 16, T. 16 S., R. 23 E. CCIIIP)sition F. F. Grout. 

Osceola ~~ble Oil & Ref1n1ng Co. 12-26-19-'H) 86 Rb;Jollte . 8,740 - 8,654 58 8,798 • P. Ha-yman No. 1 

Sec. 12, T. 31 S., R. 33 E. 

Putnam Sun 011 Co. 1-16-1949 '2. Volcanic ash and tuff ,,av - 3,841 l9 3,892 

H. E. Westbury et e.1 No. 1 ' Sec. 37, T. 11 S., R. 26 E. 

Volusia Grace Drilling Co. 1-,0-1949 44 Rb;Jolltic? volcanic ' 5,40, - 5.359 21 5,424 No cores taken 1n volRetail Lumber Co. No. 1 rock. ce.nic rock 

Sec. 2, T. 15 S., R. ,0 E. 

~l"g18. 

Atkinson Sun 011 ·co. 1-31-1945 -222 Volcanlc tuf't' or ag- ~ I 4,220 - 3,998 76 4,296 Doster - Ladson No. 1 glaaere.te cCIIIP)sed or Lot 71, Land District 7 lQdrotbemally altered 

rb;Jollte 

Camden The California Co. 3-26-1948 65 Volcanic ash and 4,674 - 4,609 281 4,955 John A. Buie No. 1 rbJol1t1c tuff 

Lat. 31° 03' 01" North 

Lo_ng. 81° 52' 48" West 

21 
Veil 

llo. 

29 

30 

31 

32 

» 

,.. 

35 

36 

"R 

,a 

39 

Greene 

Houston 

Lamar 

:r.a.ar 

Lamar 

.Marengo 

P:1clrBDs 

.ll.acbla 

Al.acbua 

Alacbua 

Baker 

I 

Talole 3. D-. on -11s ,._,..,ing Pal-ole setli-, racls ;,. Alo6a-, Flarhla anti Geargia Coastal Plain. 

( .... -.lis ........... ...._ Ia fiv-e• 1 and 2 and ..... of...__..._. on cross sectians A • A' ...1 8 • a•. The......._. of the w.lls- tt. ..aps .. d cross sections correspond to those in this table. El!"vatlons and depths expressed In feet, datum seo-level.l 

Jlame and location of' well 

Johnston & Hawkins Co. 6-12-1940 

Willis No. 1 Sec. 11, 'I'. 20 N., R. 1 E. 

Union Producing Co. 7-15-1949 E. P. K1rkland No. 1 Sec. 20, 'I'. 7 N., R. 11 W. 

Briggs & Knapp 3-24-1930 

Ve.t"el No. 1 Sec. 25. 'I'. 12 s .• R. 14 W. 

De Soto 011 & Gas Corp. 3-15-1936 

Gardner Jlo. 1 Sec •. 22, 'I'. 15 S., R. 16W. 

Stanollnd 011 & Gas Co. 8-27-1944 

Jack Vooda No. 1A 

Sec. 2}, 'I'. 14 S., R. 15 W. 

E. C. Johnston 5-25-1944 H. D. Peteet No. 1 Sec. 3, 'I'. 16 N., R. 2 E. 

\ 

C. H. llurpby, Jr. 9-11-1946 

Oden - Eaton No. 1 Sec. YJ, 'I'. 19 S., R. 16 w. 

'l'idevater-Assoc1ated Oil Co. 2-14-1947 

R. H. Cato No. 1 Sec. 23, 'I'. 8 S., R. 18 E. 

ti.dswater-Assoc1ated 011 Co. 5-11-1947 

Josle Parker No. 1 

Sec. "' 'I'. 7 S., R. 19 E. 

Tidevater-Assoc1ated 011 Co. 4- 2-1947 

J. A. Ph11'er Ro. 1 Sec. 21!-, 'I'. 9 S., R. 21 E. 

Hunt 011 Co. 6- 1-1947 

H. L. Hunt No. 1 Sec. 21, 'I'. 1 R., R. 20 E. 

130 

140 

520 

324 

417 I 

247 

315 

112 

168 

132 

130 

Lithologic char- acter of' 

Paleozoic strata 

Alabama 

Dolomite 

Quartzitic sandstone and black shale 

I 

A lithologic descrip- tion of' the Paleozoic 

rocks 1s given 1n 

I 

Geol. Survey of' 

Alabama Bull. 50, 

pp. 56-58. 1941 

'l'he lithology of' the 

Paleozo<c units <• I shown by a graphic log on Miss1ss1pp1 Geol. Society's geologic cross sect1on 

f'rom south-central 

Tennessee to central 

M1ss1ssippi. 

(Ms.rch 10, 1949) 

Hard gray llmestone 

Geol. Survey of' 

Alabama Bull. ~, 

pp. 114-116, 1 5 

Chief'ly clastic 

deposits 

Florida 

Quartz1t1c sandstone and shale. 

Quartzitic sandstone and shale. 

Quartz1t1c sandstone and shale. 

Quartzitic sandstone 

22 

2350 

7556 

135 

528 

325 

3875 

950 

3135 

3170 

3217 

3342 

Sub-sea 

elevation at top of' Paleozoic strata 

-2220 

-7416 

+ 385 

- 204 

+ 92 

-3628 

- 635 

-3023 

-3002 

-3o85 

-3212 

Depth of' pene- tration into 

Paleozoic 

strata 

266 

544 

1645 

4358 

2845 

648 

4553 

15 

50 

11 

7 

2616 

8100 

1780 

4886 

3170 

4523 

5503 

3150 

3220 

3228 

3349 

Remarks 

Ordovician~?). 2350-

2602.'1-'.D. electric log). Shreveport (La.) Geol. 

Society, 1945 Ref'erence 

Rept., vol. I, plate 3. 

In limestone of' Mississippian age at total 

depth. 

Pennsylvanian 528-2275 

Mississippian 2275-3992 

Devonian-Silurian 

3992-4886 T.D. 

Data f'rom F. F. Mellen, 

Jackson, Miss. letter 

dated Mar. 20, 1950. 

Pennsylvanian 325-1710 

Mississippian 1710-3170 

T.D. 

Data from F. F. Mellen, 

Jackson, Miss. letter 

dated Mar. 20, 1950. 

High Black River or Trenton age ( Ordov1cian) • 3875-4523 T.D. U. S. 

Geol. Survey Oil and 

Gas Inv. Prelimina.ry Chart 264 fig. 10 and 

text, 19 6. 

Pennsylvanian. 950-5503 

T. D. F. F. Mellen, 

"Black Warrior Bas1n, 

Alabama and M1ssiss1ppi", Am. Assoc. Petroleum 

Geologists Bull. vol. 31, no. 10, f'ig. 8, October 

1947. 
Taltle 3. Dala 011 wells,..,...,.., P.,._, _,,_., nte:b ill Aw-,. F,_,. sel ....,.,. c-t.l Pfo,.-C..tlneecl. 

Well County Name and location of well Date of Surface Litbologl.c char- ptb. to top Sub-sea Depth of pene- Total depth Remarks 

No. completion elevation acter or or Paleozoic elevation at tration into of well 

of well Paleozo1.c strata strata top of Paleo- Paleozoic 

zoic strata strata 

Florida--Continued. ·' 

ll-0 Bradford Titlewater-Associated Oil Co. 1- 5-19ll-7 141 ~itlc sandstone "l.4U -2999 27 3lb7 

M. F. Wiggins No. 1 and shale 

Sec. 15, T. 6 S., R. 20 E. 

41 Clay Humble Oil & Ref~ Co. 8-12-1947 115 Qpartzltlc sandstone }725 -3610 2137 5862 

Foremost Properties orp'n. 

No. 1 

Sec. 4, T. 6 S., R. 25 E. 

42 Columbia Humble Oil & Refining Co. 7-14-1948 141 Weathered zone? ,.S2 -3341 962 4444 Six diabase sills 1n 

J. P. Cone No. 1 ,.S2-3492 Paleozoic strata; see 

Sec. 22, T. 1 N., R~ 17 E. Black shale table 4. 

3492--"" 

43 Columbia Sun Oil Co. 8-24-1949 174 Qmrtzltlc sandstone 2813 -2639 15 2828 

Ruth M. Bishop No. 1 and shale. 

Sec·. 10, T. 4 S., R. 17 E. 

44 Columbia Sun Oil Co. 5-31-1949 87 Qpartzltlc sandstone 3033 -29ll6 18 3051 

W. F. Johnson No. 1 

Sec. 27 - T. 4 S., R. 16 E. 

45 Columbia sun·Oil Co. 7- 4-1949 124 Qmrtzltlc sandstone 2922 -2798 7 2929 

Clarence Loyd No. 1 and shale 

Sec. 11, T. 5 S., R. 17 E. 

46 Columbia Sun Oil Co. ll-16-1948 138 Black shale 3303 -3165 8 3311 

M. W. Sa~ No. lA 

Sec. 24, • 2 s., R. 16 E. 

47 Dixie Stano lind Oil & Gas Co. and 8- 8-1946 33 QJJ&rtzltlc sandstone 5228 -5195 2282 7510 

Sun Oil Co. 

Perpetual Forest, Inc·. No. 1 - Sec. 5, T. ll s., R. ll E. 

48 D1x1e Sun Oil Co. 3- 6-1949 41 Sandstone and shale 5016 . -4975 88 5104 

P. C. Crapps "A", well No~ 1 

Sec. 36, T. 8 S., R. 10 E. 

49 Dixie Sun Oil Co. ll-10-1946 33 Qpartzltlc sandstone 3645 -3612 26 3671 

Hazel ~ton No. 1 and shale 

Sec. 8, T. 8 S., R. 14 E·. 

50 Gilchrist Sun Oil Co. 3-27-1946 93 Qpartzltlc sandstone 3588 -3495 165 3753 

Alto Adams No. 1 and shale 

Sec. 15, T. 9 S., R. 15 E. 

51 Gilchrist Sun Oil Co. 9-30-1948 77 Qpartz.itlc sandstone 3348 -3271 18 3366 

Williams Bros. No. 1 and shale 

Sec. 12, T. 8 S., R. 15 E. 

52 Hernando Ohio Oil Co. 6-23-1946 47 Qpartzitlc sandstone 7720 -7673 752 8472 

Hernasco Corp. No. 1 

Sec. 19, T. 23 S., R. 18 E. 

53 Jackson Humble Oil & Refining Co. 3-14-1949 128 Red and gray sandstone 84Jio -8312 8o5 9245 Two basalt sills 1n Pale 

C. W. Tindel No. 1 and shale zoic strata; see table 4. 

Sec. 8, T. 5 N., R. ll W. 

54 Jefferson Coastal Petroleum Co. 1-10-1949 51 Qpartz:l.tlc sandstone 7909 -7858? 4? 7913 Paleozoic age of quartE. P. Larsh No. 1 zitic sandstone not 

Sec. 1, T. 2 S., R. 3 E. def1n1tely determined. 

55 Lafayette. Coastal Petroleum Co. 3-19-1949 45 QJJ&rtzitlc sandstone ,wo -3435 27 3507 

Ronald Sapp No. 1 and sbal.e 

Sec. 18, T. 6 S., R. 14 E. 

56 Lafayette Gulf Oil Corp. 10- 5-1949 87 Qmrtzitic sandstone 4505 -4418 7 4512 

Brooks-Scanlon, Inc. Block 49, 

well No. 1 

Sec. 36, T. 5 S., R. 10 E. 
T .... 3. D-. • wells,_.,,_, Paleozok s.Ji..,Y rocb Ia AI.,_, Fl ... ltla aeJ G.•gla Coastal P/ain-Contlnu.d. 

Well County Name and location of well Date of Surf' ace Lithologic char- Depth to top Sub-sea Depth of pene- Total depth Remarks 

No. completion elevation acter of of Paleozoic elevation at tration into of well 

of well Paleozoic strata Strata top of Paleo- Paleozoic 

zoic strata strata li'lnT'· 1A-- ue • 

57 Lal'ayette Humble Oil & Refining Co. 2-19-lgJI.B 52 Quartz! he sa.nd.s tone !1-205 -4153 30 4235 

R. L. Henderson No. 1 and shale 

Sec. 20, T. 4 S., R. 11 E. 

58 Lal'ayette Sun 011 Co. 1-26-19116 70 Quartz! tic sandstone 4o30 -3960 103 4133 

P. C. Crapps No. 1 and shale 

Sec. 25, T. 6 S., R~ 12 E. 

59 Levy Coastal Petroleum Co. 10-18-1947 14 Black shale 5810 -5796 40 5850 

J. B. and J. T. Ragland No. 1 

Sec. 16, T. 15 S., R. 13 E. 

6o Levy Humble 011 & Refining Co. 8-20-1949 58 Six inches of al tared 4377 -4319 232 4609 Basalt overlies Paleozoic 

C. E. Robinson No. 1 black shale overlying strata; see table 4. 

Sec. 19, T. 16 S., R. 17 E. quartzitic sandstone. 

61 Levy sun ·on co. 6- 8-19116 34 Quartzitic sandstone 396o -3926 37 3997 

J. T. Goethe No. 1 

Sec. 31, T. 14 S., R. 17 E. 

62 Madison Hunt 011 Co. 5-31-1944 107 Black shale 4628 -4521 757 5385 

J. W. Gibson No. 2 

Sec. '6, T. 1 S., R. 10 E. 

63 Madison Hunt 011 Co. 5-18-1945 73 Quartzitic sands tone 4o6o -3987 36 4096 

J. W. Gibson No. 4 and shale 

Sec. 5, T. 2 S., R. 11 :&:. 

64 Marion J. S. Cosden 3-13-1928. 195 Quartzitic.sandstone 3660? -3465 674? 4334 

W. L. Lawson No. 1 

Sec. 25, T. 13 S., R. 20 E. 

65 Marion Ocala 011 Corp. July - 1928 8o Quartzitic sandstone 4100? -4020? 2o80? 6180 

Clark-Ray-Johnson No. 1 

Sec. 10, T. 16 S., R. 20 E. 

23 Marion Sun 011 Co. 5-20-1947 74 Quartzitic sandstone 424o -4166 375 4637 4615-4637 T. D. Volcanic 

Henry N. Camp No. 1 agglomerate; see table 2. 

Sec. 16, T. 16 S., R. 23 E. 

66 Marion Sun 011 Co. 4-23-1949 79 Quartzitic sandstone 3679 -3600 166 3845 

H. T. Parker No. 1 

Sec. 24, T. 14 S., R. 22 E. 

'67 Nassau St. Mary's River Oil Corp. 1940 110 Black shale 4640 -4530 168 4824 48o8-4824 T. D~ dtabase; 

Hilliard T~ntine Co. No. 1 see table 4. 

Sec. 19, T. N., R. 24 E. 

68 Putnam Sun Oil Company and Seaboaro 7-23-1947 206 Quartzitic sandstone' 3320 -3114 8 3328 

Oil Co. 

Q. I. Roberts Nc. 1A 

Sec. 19, T. 9 S., R. 25 E. 

69 Suwannee Sun Oil Co. 1- 4-1947 73 Black shale 3040 -2967 121 3161 

Earl Odom No. 1 

Sec. 31, T. 5 S., R. 15 E. 

70 Suwannee Sun Oil Co. 7-31-1949 96 Quartzitic sandstone 3136 -304o 3 3139 A. B. Russell 

Sec. 8, T. 5 s. , R. 15 E. 

71 Suwannee Sun Oil Co. 9- 1-1947 162 Black shale 3500 -3338 72 3572 

J. H. Tillis No. 1 

Sec. 28, T. 2 S., R. 15 E. Georgia 

72 I Clinch I Hunt Oil Co. ,1-18-19441 147 I Black shale 3953 I 

-3806 I 135 I 4088 I Alice Mus ve No. 1 

Lot 198, ~ District 12 

24 
Table 3, Data 011 wells pe11etrflflrtg Paleozoic sedl-nfoty1

roclcs /11 Alabalfla, Fl.,.ida and GeO<gia Coastal Plaiii··Continued. 

Well County Name and location of well Date of Surface Lithologic char- Depth to top Sub-sea Depth of pene- Total depth Remarks 

No. completion elevation acter of of Paleozoic elevation at tration into of well 

of well Paleozoic strata Strata 1;0p of Paleo- Paleozoic 

zoic strata strata Geor~ a-- on nue 

73 Early Mont Warren et al 10- 2-1943 ltl7 Black shale 6950- 6950 -6763 370 7320 

A. C. Chandler No. 1 72.1!-0.Quartzitic 

Lot 406, Land District 26 sandstone 7240-7320 

74 Echols Humble Oil & Refining Co. 5- 6-1949 181 Sandstone and shale 4108 -Y927 77 4185 Diabase sill in Paleozoic 

Bennett and Langsdale No. 1 strata; see table 4. 

Lot 146, Land District 12 

75 Echols Hunt Oil Co. 10-10-1944 148 Black shale 3782 -3634 83 3865 

Superior Pine Products Co. 

No. 1 

Lot 364, Land District 13 

76 Echols Hunt Oil Co. 4- 7-1945 142 Quartzitic sandstone 3730 -3588 332 4062 

Superior Pine Products Co. 

No. 2 

Lot 317, Land District 13 

77 Echols Hunt Oil Co. 7-29-1947 143 Weathered zone? 3657 -3514 346 4003 

Superior Pine Products Co. 3657-3735 

No. 3 Black shale 

Lot 532 1 Land District 13 3735-4003 

78 Echols Hunt Oil Co. 3-16-1948 156 Red micaceous silty 3911 -3755 5 3916 

Superior Pine Products Co. shale; weathered 

No. 4 zone? 

Lot 219, Land District 13 

25 
Table 4: Dota on wells encountering Triassic? diabase and basalt In Alabama, Florida, and Georgia Coastal Plain. 

[The wells here listed are shown in figures 1 and 2 and some of them are shown on cross sections A ·A' and B ·B'. The numbers of the wells on the maps and cross sections correspond to those In this table. 

Elevations and depths expressed in feet, datum sea-level. *Igneous rock determinations by Charles Milton, u.S. Geological Survey. **Igneous rock determinations by Frank F. Grout, Visiting Professor 

of Geology, Florida Stote University, Tallahassee, Fla.] 

Well 

No. 

County Name and location of well 

79 Barbour W. B. Hinton et al 

J. S. Creel No. l 

Sec. 14, T. 9 N., R. 26 E. 

80 Barbour H. A. Stebinger 

Alice S. Robertson No. 1 

Sec. 19, T. 10 N., R: 26 E. 

42 Columbia Humble Oil & Refining Co. 

J. P. Cone No. l 

Sec. 22, T. lN., R. 17 E. 

53 Jackson Humble Oil & Refining Co. 

C. W. Tindel No. l 

Sec. 8, T. 5 N., R. 11 W. 

54 Jefferson Coastal Petroleum Co. 

60 Levy 

E. P. Larsh No. 1 

Sec. l, T. 2 S., R. 3 E. 

Humble Oil & Refining Co. 

C. E. Robinson No. 1 

Sec. 19, T. 16 S., R. 17 E. 

62 Madison Hunt Oil Co. 

J. w. Gibson well no. 2 

Sec. 6, T. l S., R. 10 E. 

63 Madison Hunt Oil Co. 

J. W. Gibson well no. 4 

Sec. 5, T. 2 S., R. 11 E. 

67 Nassau St. Mary's River Oil Corp. 

Hilliard Turpentine Co. No. l 

Sec. 19, T. 4 N., R. 24 E. 

81 Taylor Gulf Oil Corp. 

Brooks-Scanlon, Inc., Block 33, 

well No. 1 

Sec. 18, T. 4 s., R. 9 E. 

82 Taylor Gulf Oil Corp. 

83 Taylor 

Brooks-Scanlon, Inc., Block 42, 

well no. l 

Sec. 9, T. 8 S., R. 9 E. 

Humble Oil & Refining Co. 

G. H. Hodges No. l 

Sec. 12, T. 5 S., R. 6 E. 

Date of 

completion 

10-26-1939 

3-14-1939 

7-14-1948 

3-14-1949 

l-10-1949 

8-20-1949 

5-31-1944 

2- 4-1950 

12- 1-1949 

10-28-1948 

Surface 

elevation 

~ 

504 

141 

128 

51 

107 

73 

110 

41 

Total depth Depth to igneous rock 

of well Top Bottom 

5546 

5215 

Flor1da 

4444 

7913 

4609 

4824 

5517 

*4135 

*4202 

*4273 

*3529 

3564 

4191 

*4193 

*4248 

*4267 

**8890 

8970 

*7763 

*7850 

4044 

4808 

5200 

6153 

5372 

5522 

4152 

4208 

4274 

3562 

3565 

4192 

4195 

4251 

4270 

8932 

8983 

7792 

7890 

4377 

4628 

4060 

Remarks 

Diabase sills or dikes in clastic rocks of Triassic(?) 

age. Not studied petrographically. 

*Diabase sills or dikes in clastic rocks of Triassic(? 

age. 

*Diabase and amygdular basalt sills in black shale of 

Paleozoic age. 3564-65 not studied petrographically. 

Not studied petrographically. 

**Porphyritic hornblende basalt. A small intrusive 

or flow in Paleozoic.clastic rocks; see table 2. 

Not studied petrographically. 

*Diabase and related kinds of volcanic rocks. Sills 

or ·dikes in clastic rocks of Triassic(?) age. 

*4317-4344 decomposed igneous rock; underlies Lower 

Cretaceous sandstone. 

*4344-4377 basalt; overlies altered black shale of 

Paleozoic age; see table 2. 

Diabase; not studied petrographically. Underlies 

Lower Cretaceous or older Mesozoic rocks; overlies 

black shale of Paleozoic age. 

Diabase; not studied petrographically. Underlies 

Lower Cretaceous or older Mesozoic rocks; overlies 

quartzitic sandstone of Paleozoic age. 

48o8-4824 T. D. diabase sill or dike. Underlies 

black shale of Paleozoic age; see table 2. Determination from Am. Assoc. Petroleum Geologists Bull., 

vol. 28, no. 12, p. 1723, Dec. 1944; and Florida Geol. 

Survey Bull. 26, p. 94, 1944. 

**5200-5243 T. D. diabase gabbro; underlies clastic 

rocks of Triassic(?) or Jurassic(?} age. 

**5438-5517 T. D. diabase; probably a lava flow. 

Underlies clastic rocks of Triassic(?) or Jurassic(?) 

age. 

*6153-6165 basaltic rock; underlies clastic rocks of 

Triassic(?) or Jurassic(?) age. 

**6165-6254 T. D. diabase gabbro. 
Well 

No. 

84 

85 

74 

86 

87 

88 

Appling 

Calhoun 

Echols 

Laurens 

Mitchell 

MontgomeiJ 

Table 4. Data on wells encountering Triassic? diabase and basalt in Alabama, Florida and Georgia Coastal Plain-Continued 

Name and location of well 

Felsenthal and Weatherford 

Mrs. W. E. Bradley No. 1 

Lot 522, Land District 2 

~owega Minerals Exploration 

Co. 

J. W. West No. 1 

Lot 328, Land District 4 

Humble Oil & Refining Co. 

Bennett and Langsdale No. 1 

Lot 146, Land District 12 

Calaphor Manufacturing Co. 

Grace McCain No. 1 

~mile south of Minter, Ga. 

Stanolind Oil & Gas Co. 

J. H. Pullen No. 1 

Lot 133, Iand District 10 

J. E. Weatherford 

Lonnie Wilkes No. 1 

~ mile south of Higgston, Ga. 

Date of 

completion 

7-30-1947 

1-13-1950 

5- 6-1949 

7-10-1945 

8-14-1944 

5- 9-1946 

229 

345 

181 

280 

338 

293 

Georgia 

4106 

5265 

4185 

2548 

7487 

3433 

Depth to igneous rock 

Top Bottom Remarks 

4095 **4095-4106 T. D. altered amygdaloidal basalt; 

probably a lava flow. Basalt underlies Lower Cretaceous or older Mesozoic rocks. 

5190 *5190-5265 T. D. diabase; underlies Lower Cretaceous 

or older Mesozoic rocks. 

4125 4150 *Diabase sill or dike in Paleozoic clastic rocks; see 

table 2. 

2532 *2532-2548 T. D. diabase; underlies Lower Cretaceous 

or older Mesozoic rocks. 

6550 6620 Not studied petrographically. 

7070 7090 Not studied petrographically. 

*7350 7470 *Diabase sills or dikes in clastic rocks of Triassic(? 

age. 

3415 *3415-3433 T. D. diabase; underlies Lower Cretaceous 

or older Mesozoic rocks. 
Table 5. Data an significant Jeep wells in Alabama, Florida and Georgia Coastal Plain which JiJ not reach pre-Mesozoic rocks. 

[The wells here listed are shawn in figures 1 m1d 2 and same of them are shown on cross section A. A'. The numbers of the well• on the maps m1d cross section correspond to those In this 

toble. Elevations and depths expressed In feet, datum sea-leve~] 

Well 

.No. 

89 

90 

91 

92 

93 

94 

95 

96 

97 

98 

99 

100 

Clarke 

Crenshaw 

Escambia 

Washington 

Charlotte 

Collier 

Dade 

Monroe 

Monroe 

Palm Beach 

Pinellas 

Clinch 

.Name and location of well 

Union Producing Co. 

M. M. Waite No. 1 

Sec. 27, T. 8 N., R. 1 w. 

Nelson Exploration Co. 

Smith Lumber Co. No. 1 

Sec. 26, T. 8 N., R. 16 E. 

Humble Oil & Refining Co. 

Minnie E. Skinner No. 1 

Sec. 10, T. 3 N., R. 10 E. 

Humble Oil & Refining Co. 

J. R. Williams No. 2 

Sec. 21, T. 6 N., R. 4 W. 

Humble Oil & Refining Co. 

Lowndes-Treadwell No. lA 

Sec. 17, T. 42 S., R. 23 E'. 

Humble Oil & Refining Co. 

Gulf Coast Realties Corp. No. 2 

Sec. 30, T. 48 S., R. 30 E. 

Humble Oil & Refining Co. 

State of Florida No. 1 

Sec. 30, T. 55 S., R. 36 E. 

Gulf Oil Corp. State of Florida No. 1, Lease 

No. 373. 

Sec. 2, T. 67 S., R. 29 E. 

Peninsular Oil & Refining Co. 

J. W. Cory No. l 

Sec. 6, T. 55 S., R. 34 E. 

Humble Oil & Refining Co. 

Tucson Corp. No. l 

Sec. 35, T. 43 S., ~· 40 E. 

Coastal Petroleum Co. 

E. C. Wright No. l 

Sec. 7, T. 30 S:, R. 17 E. 

Sun Oil Co. 

W. J. Barlow No. 1 

Lot 373, Land District 12 

Alabama 

10-22-1941 38 

5-27-1948. 396 

9- 5-1944 269 

2- 8-1949 264 

Florida 

12-30-1945 20 

10- 2-1944 34 

3- 6-1945 15 

4- 1-1947 23 

5-21-1939 14 

8- 8-1947 34 

7- 2-1948 13 

Georgia 

3- 5-1947 177 

28 

Total depth of well 

12,399 

10,830 

11,100 

15,659 

13,304 

13,512 

11,794 

15,455 

lO,Oo6 

13,375 

11,507 

3,847 

Oldest 

formation 

enetrated 

Jurassic 

Triassic(?) 

Lower Cretaceous or Older Mesozoic. 

Jurassic 

Lower Cretaceous. 

Trinity a~ (Lower Cretaceous) . 

Lower Cretaceous. 

Jurassic(?) 

Lower Cretaceous. 

Jurassic(?) 

Lower Cretaceous. 

Lower Cretaceous(?)