CORRELATION OF THE EOCENE FORMATIONS IN MISSISSIPPI AND ALABAMA 

By WYTHE CooKE 

INTRODUCTION 

During Eocene time the site of the boundary between the States of Mississippi and Alabama fell 

within the transition zone between the ¥ississippi 

embayment and the open Gulf of Mexico. That different types of deposition proceeded simultaneously 

within these two regions may be inferred from the 

different facies which deposits of the same age exhibit 

on opposite sides of the State line. In general, much 

clay and carbonaceous mate,rial were laid down in 

Mississippi, while shell marl, laminated sand, and 

limestone were being formed in Alabama. The purpose of this paper is to point out the equivalences of 

formations of different facies in the two States. The 

correlation adopted is shown in the following table, 

all the formation names in which have been previously used, except Kosciusko sandstone, a new name 

proposed for a member of the Lisbon formation. 

Correlation of Eocene formations in Mississippi and Alabama 

Mississippi Alabama 

I 

Yazoo clay member Jackson Jackson Ocala limestone ····························-······················---------·---·--·-········------------·····-------------- forma- formation east of Tombigbee River 

Moodys marl member tion 

Yegua formation 

I· Gosport sand 

i 

P. 

;::! I 

0 

bh Lisbon ························-····················-------------------- --········----------------················ 

~ 

~ forma- Kosciusko sandstone member Lisbon formation 1-o 

0 tion 

:9 --··········-·····------------------------------------ -----·----------- -- -- ---·- --· ···········----- -- -- -- -

~ Winona sand member 0 I 

Tallahatta formation 

OverGrenada formation lapped Hatchetigbee formation area 

0.. 

;::! Absent Bashi formation 0 

6h 

M I 0 

0 Holly Springs sand Tuscahoma formation 

~ Over- Over- lapped near Ackerman formation lapped Nanafalia formation Tennessee 

boundary area 

Unex- I 

0.. Porters Tippah sandstone member plored Naheola formation ;::! 

0 Creek area to 

~ clay ...................... ....................... .. ............................. 

I I a= Sucarnochee clay Overlapped area '"t:l 

~ ' 

Clayton formation 

I 

133 I 

• 
134 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

The Eocene of the Gulf region is commonly divided 

into four parts-the Midway, Wilcox, and Claiborne 

groups and the . Jackson formation. The types of the 

Midway, Wilcox, and Claiborne groups are based on 

the superb sections of Eocene strata exposed along 

Alabama and Tombigbee rivers. These sections, as 

interpreted by Prof. Eugene A. Smith and his associates, have long been the standard for comparison with 

sections in other parts of the Gulf Coastal Plain. 

The type of the youngest division of the Eocene, the 

Jackson formation, is in Mississippi. 

MIDWAY GROUP 

The Midway group is divisible into three formations-the Clayton formation (at the base), the Porters Creek or Sucarnochee clay, 'and the Naheola formation. These three seem to constitute a conformable 

series but at plaqes may be separated from one another 

by local unconformities. The group is set off from 

the underlying Cretaceous rocks by a profound unconformity and from the overlying Wilcox group by a less 

conspicuous break. 

The Clayton is thickest in the neighborhood of 

Chattahoochee River, the eastern boundary of Alabama, and thins toward the west. In western Alabama and in Mississippi it is reduced to a thin bed of 

limestone, and over a considerable area in both States 

it is completely overlapped by the Porters Creek or 

Sucarnochee clay. The Porters Creek, . on the other 

hand, is thickest in Tennessee . or Mississippi and 

pinches out entirely or is completely overlapped about 

midway across Alabama. It is probable that the two 

formations are partly contemporaneous, but the base 

of the Clayton is doubtless older than any part of the 

Porters Creek. The N aheola formation, consisting 

prevailingly of highly micaceous yellow to red sand, 

extends across Alabama into Mississippi at least as far 

north as De Kalb. The Tippah sandstone member 

' ' at the top of the Porters Creek clay in northern Mississippi, is probably of the same age as the N aheola 

formation, and it is not unlikely that the two could be 

united on the map by more detailed field work. It is 

perhaps significant that deposits of bauxite occur in 

clays tentatively correlated with the N aheola formation in Henry County, Ala., and also above the characteristic Porters Creek clay and beneath lignitiferous 

beds of the Ackerman formation (Wilcox group) at 

several places in Mississippi. 

WILCOX GROUP 

The formations of the Wilcox group in Mississippi 

differ much more markedly from those of the typical 

Wilcox of Alabama than the Midway formations in 

Mississippi differ from the Midway of Alabama. The 

State line lies not far from a natural boundary or 

transition zone which separates areas differing in type 

of deposists. It has been necessary to assign different 

names on opposite sides of the State line to several 

divisions of the Wilcox group. 

The classic work of E. A. Smith and others, culminating in 1894 in their reporton the geology of the 

·Alabama Coastal Plain,t separated the Wilcox group 

of Alabama into four formations-the Nanafalia 

(lowest), Tuscahoma, Bashi, and Hatchetigbee. The 

first separation of the Wilcox group of Mississippi into 

formations was made in 1913, by E. N. Lowe,2 who 

named the Ackerman (lowest), Holly Springs, and 

Grenada formations. Two years later 3 he added the 

"Woods Bluff formation," an alternate name for the 

Bashi formation, basing his recognition upon fossils 

identified by me. Berry 4 in 1917 pointed out the 

presence of the Hatchetigbee formation near Meridian. 

The Nanafalia formation, which forms the base of 

the Wilcox group in Alabama, extends from Chat-

. tahoochee River at Fort Gaines, Ga., as far west 

as the junction of Y antley and Tickabum creeks in · 

Choctaw County but has not been recognized in 

Mississippi. It contains a considerable proportion of 

hard rock resembling the buhrstone of the Tallahatta 

formation (of the Claiborne), which distinguishes it 

from the other parts of the Wilcox group, and it is 

further distinguished by carrying a great profusion of 

Ostrea thirsae. 

In Mississippi the position at the base of the Wilcox 

group is occupied by the Ackerman formation, which 

is most extensively developed· in the middle part of 

its belt ·of outcrop and pinches out near the Tennessee 

line on the north and near the Alabama line on the 

east. It consists of gray, rather massive clays, some 

of which are lignitic, and contains a peculiar flora. 

No marine fossils have been found in it. The Ackerman formation is tentatively correlated with the 

Nanafalia formation on the basis of its apparent 

stratigraphic position, but it may be equivalent to the 

lower part of the Tuscahoma formation of Alabama. 

The Tuscahoma formation extends entirely across 

Alabama and abuts against the Holly Springs s·and 

at the Mississippi line. Its most characteristic 

lithologic facies are very fine laminated gray sand and 

clay and. yellow sand containing angular tilted blocks 

of laminated clay. Both of these facies are found 

also in the Holly Springs sand in eastern Mississippi. 

It is obvious that the Holly Springs is equivalent to 

at least part of the Tuscahoma, but whether or not 

both formations occupy the sam~ stratigraphic 

interval would be difficult to prove. No marine 

fossils have been found in the Holly Springs to compare with a rather characteristic fauna in the type 

1 E. A. Smith, Johnson, L. C., and Langdon, D. W., jr., Report on the geology of 

the Coastal Plain of Alabama, Alabama Geol. Survey, 1894. 

2 Preliminary report on iron oreS of Mississippi: Mississippi Geol. Survey Bull. 

10, pp. 23-25, 1913. 

1 Mississippi Geol. Survey Bull. 12, p. 71, 1915. 

• Berry, E. W ., Geologic history indicated by the fossiliferous deposits or the Wil· 

cox group (Eocene) at Meridian, Miss.: U.S. Geol. Survey Prof. Paper 108,p. 62, 

1917. 
CORRELATION OF EOCE.NE. FORMATIONS·, MISSISSIPPI AND ALABAMA 135 

area of the Tuscahoma, and too few plant remains 

are known from the Tuscahoma to furnish an adequate 

basis for comparison with the large flora of the Holly 

Springs. 

The Bashi formation crops out along a narrow band 

extending nearly across Alabama but apparently is 

covered by an overlap of Hatchetigbee clays in 

western Choctaw County, near the Mississippi line. 

In Mississippi it has been recognized" at only two 

localities near Meridian, but shells reporte.d by Hilgard 5 from sec. 33, southwest of Marion and 2 or 3 

miles north of Meridian, although referred by him to 

the Claiborne, probably came from the Bashi formation. The characteristic feature of the Bashi is a 

marl bed which has become locally indurated into gray 

pillow-like nodules of speekled madstone or impure 

limestone. The marl at most places contains a large 

and varied fauna of mollusks. 

Overlying the Bashi formation at Meridian and 

apparently overlapping for several miles beyond the 

Bashi is the Hatchetigbee formation, which is made up 

.of brown or chocolate-colored, more or less carbonaceous clay and gray sand. In Mississippi the 

Hatchetigbee appears to be restricted to. Lauderdale 

County, of which it covers somewhat more than 30Q 

square miles, and the northeast corner of Clarke 

County. In Alabama its belt of outcrop extends 

across the State but is interrupted by overlaps of 

younger formations at the eastern extremity. Fossil 

leaves taken from ·Hatchetigbee clay at Meridian 

correlate the formation closely with the . Grenada of 

northwestern Mississippi. 6 The Grenada formation, 

which is very similar in appearance to the Hatchetigbee, 

has been mapped from the vicinity of Duck Hill, 

Montgomery County, Miss., northward to the Tennessee. line and is known to extend for a considerable 

distance into Tennessee. 

CLAIBORNE GROUP 

The Claiborne group is divided into three formations-the Tallahatta (lowest), Lisbon, and Yegua 

formations in Mississippi and the Tallahatta and 

Lisbon formations and Gosport sand in Alabama. 

The Tallahatta formation extends from Grenada 

County, Miss., where it emerges from beneath the 

loess, eastward across Mississippi and Alabama and 

is still recognizable across Chattahoochee River at 

Fort Gaines, Ga. The formation nearly everywhere 

is easily identifiable by its. characteristic lithology, 

consisting chiefly of brittle claystone or diatomaceous 

earth and hard sandstone with angular lumps of daystone, but in eastern Alabama these rocks are not 

conspicuous and most of the formation is composed 

1 Hilgard, E. W ., Geology and agriculture of the State of Mississippi, p. 12 , 1860. 

o Berry, E. W., Geologic history indicated by the fossiliferous deposits of the 

Wilcox group (Eocene) at Meridian, Miss.: U. S. Geol. Survey Prof. Paper 108, 

pp. 61-72, 1917. This correlation was suggested by Lowe in Mississippi Geol. 

Survey Bull. 12, p. 72, 1915. 

of loose sand. Crider 7 and Lowe 8 included in the 

Tallahatta certain beds of quartzitic to granular sandstone I which are most extensively developed in At tala 

and adjoining counties of Mississippi but are here 

regarded as a local facies of the Lisbon formation. 

Lowe divided the Tallahatta formation into two 

parts-a lower, called the Winona sand, and an upper, 

called the "Basic claystone." He regarded the sandstone of Attala County as equivalent to the "Basic 

elaystone," which is typical Tallahatta formation, but 

the buhrstone of the Tallahatta can be traced beneath the typical Winona, whieh underlies the sandstone. The Winona is here treated as the basal 

member of the Lisbon formation. 

In Alabama the Lisbon formation consists of two 

parts to which individual names have not been applied. 

The lower part consists chiefly of fine yellow or reddish 

sand and pale-green flaky clay. The upper part is 

made up of calcareous clay, impure limestone, or 

shell marl. 

Lowe 9 has divided the Lisbon of Mississippi into 

four members- the "Enterprise green marl" (lowest), 

''Decatur sand," "Wautuhbee marls," and "Cockfield beds." The last is usually regarded as synonymous with theY egua formation of Texas and Louisiana 

and is treated as an independent formation overlying 

the Lis bon. The names ''Ente-rprise'' and ''Decatur'' 

have been dropped because they had already been 

used for a shale and a limestone in. Kansas and Tennessee. 

The "Enterprise marl," named from a village in 

Clarke County, contains ___ a great deal of glauconite, 

which, on weathering, gives rise to highly ferruginous · 

red beds. These red beds are perhaps the most conspicuous member of the Lisbon formation and can 

easily be traced northwestward along a belt adjacent 

to the outcrop of the Tallahatta formation. They 

appear to merge into the typical Winona sand. As 

the name "Enterprise" is preoccupied, the Winona 

sand is here redefined so as, to include the typical 

Winona sand of Montgomery County and the typical 

"Enterprise marl" of Clarke County but to exclude 

the sands at the base of the Tallahatta formation in 

Lauderdale County which were erroneously correlated 

with the Winona by Lowe. 

Above the Winona red beds lie sand beds called 

the "Decatur sand" by Lowe. The ledges of hard 

sandstone in Attala County referred to in the discussion of the Tallahatta formation appear to represent 

an indurated facies of these sands. The name Kosciusko sandstone member is here proposed as a designation for the ledges of saccharoidal to quartzitic 

7 Crider, A. F., Geology and mineral resources of Mississippi: U. S. Geol. Survey 

Bull. 283, pp. 29-32, 1906. . 

s Lowe, E. N., Mississippi, its geology, geography, soil, and mineral resources: 

Mississippi Geol. Survey Bull. 12, pp. 72-76, 1915; Bull. 14, pp. 73-76, 1919. 

o Lowe, E. N., Mississippi Geol. Survey Bull. 12, pp. 76-78, 1915; Bull. 14, pp. 

77-79, 1919. 
136 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

sandstone exposed in the vicinity of Kosciusko, the 

county seat of Attala County, Miss., and for the 

unconsolidated sands of the same age in Mississippi. 

The name "Decatur sand," being preoccupied, will 

be dropped. 

The "Wautubbee marls," which lie at the top of the 

Lisbon formation in Mississippi, carry the characteristic Lisbon fauna and may be regarded as the equivalent of the upper or typical part of the Lisbon of 

Alabama, which they closely resemble. For this reason it seems better to regard them not as a member of 

the formation but as the undivided part of the formation, and the local name is not needed. 

The famous sand bed at Claiborne, Ala., which has 

yielded so many beautiful. shells, is now called the 

Gosport sand. It is the topmost formation of the 

Claiborne group. It is nowhere very thick and, except 

for its shells, is not very significant. It contains a few 

lenses of leaf-bearing clay which suggest correlation 

with the Y egua formation. The Gosport lies conformably on the Lisbon formation and is overlain by 

the ScuteZZa-bearing bed at the base of the Ocala 

limestone. 

A series of beds of carbonaceo~s sand and clay, the 

extension of the Y egua formation of Texas, crosses 

Louisiana and Mississippi, rapidly thins toward the 

east, and probably merges with the Gosport sand in 

Alabama. The correlation of the Y egua with the 

Gosport is based primarily upon the stratigraphic 

position of both between the Lisbon and the Jackson, 

for the paleontologic evidence is inadequate. Of the 

14 species of plants recorded from the Gosport sand 

only 7 are included in the list of 66 from the Yegua.10 

DEPOSITS OF JACKSON AGE 

Deposits of Jackson age form the upper division of 

the Eocene. They lie conform·ably above the Claiborne group and below the Vicksburg group (Oligocene). Two formations, the typical Jackson formation and the .Ocala limestone, are recognized in this 

division of the Eocene in Mississippi and Alabama, 

and they are regarded as contemporaneous.U Many 

fossils are common to the two formations, but each 

has some peculiar species. The formations differ 

in lithology. 

The Jackson formation in Mississippi consists of 

two members-the Moodys marl at the base and the 

Yazoo clay at the top. The Moodys marl contains 

the celebrated shell bed from which many beautifully 

preserved fossils have been taken but is not otherwise 

notable. The Yazoo clay is much thicker and more 

extensive and is the horizon of Basilosaurus cetoides, the 

'' zeuglodon.'' The Jackson formation extends from 

the bluffs bordering the Yazoo Delta eastward acros~ 

Mississippi and into Alabama as far as Tombigbee 

River, where it merges into the Ocala limestone. 

The Ocala limestone extends eastward from Tomhigbee River across Alabama and is widely distributed 

in Florida and southwestern Georgia. 

to Berry, E. W., The middle and upper Eocene floras of southeastern North 

America: U. 8. Geol. Survey Prof. Paper 92, p. 31, 1924. 

u Cooke, C. W., Correlation of the deposits of Jackson and Vicksburg ages in 

Mississippi and Alabama: Washington Aead. Sci. Jour., vol. 8, pp.186-198, 1918.