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Home , Alabama, Midway Group, Mississippi, Tallahatta Formation, Wilcox Group

CORRELATION OF THE FORMATIONS IN AND

By WYTHE CooKE

INTRODUCTION clay and carbonaceous mate,rial were laid down in During Eocene time the site of the boundary be­ Mississippi, while shell marl, laminated sand, and tween the States of Mississippi and Alabama fell were being formed in Alabama. The pur­ within the transition zone between the ¥ississippi pose of this paper is to point out the equivalences of embayment and the open Gulf of . That dif­ formations of different facies in the two States. The ferent types of deposition proceeded simultaneously correlation adopted is shown in the following table, within these two regions may be inferred from the all the formation names in which have been previ­ different facies which deposits of the same age exhibit ously used, except Kosciusko sandstone, a new name on opposite sides of the State line. In general, much 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 formation forma- east of Moodys marl member tion I· Yegua formation Gosport sand i P. ;::! I 0 ························-····················------· ·······------················ bh Lisbon ~ ~ forma- Kosciusko sandstone member Lisbon formation 1-o 0 tion :9 --··········-·····------·------· - --· ···········------• ~ 0 Winona sand member I

Over- Grenada formation lapped Hatchetigbee formation

0.. ;::! 0 Absent Bashi formation 6h M 0 0 Holly Springs sand Tuscahoma formation ~ I Over- lapped near Over- Ackerman formation lapped Nanafalia formation boundary area

Unex- I 0.. Tippah sandstone member plored Naheola formation ;::! Porters area 0 Creek to clay ...... ~ a= Sucarnochee clay Overlapped area '"t:l I I ~ '

133 I I 134 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 The Eocene of the Gulf region is commonly divided names on opposite sides of the State line to several into four parts-the Midway, Wilcox, and Claiborne divisions of the . groups and the.Jackson formation. The types of the The classic work of E. A. and others, cul­ Midway, Wilcox, and Claiborne groups are based on minating in 1894 in their reporton the geology of the the superb sections of Eocene strata exposed along ·Alabama Coastal ,t separated the Wilcox group Alabama and Tombigbee rivers. These sections, as of Alabama into four formations-the Nanafalia interpreted by Prof. Eugene A. Smith and his associ­ (lowest), Tuscahoma, Bashi, and Hatchetigbee. The ates, have long been the standard for comparison with first separation of the Wilcox group of Mississippi into sections in other parts of the . formations was made in 1913, by E. N. Lowe, 2 who The type of the youngest division of the Eocene, the named the Ackerman (lowest), Holly Springs, and Jackson formation, is in Mississippi. Grenada formations. Two years later 3 he added the "Woods Bluff formation," an alternate name for the Bashi formation, basing his recognition upon fossils The Midway group is divisible into three forma­ identified by me. Berry 4 in 1917 pointed out the tions-the Clayton formation (at the base), the Por­ presence of the Hatchetigbee formation near Meridian. ters Creek or Sucarnochee clay, 'and the Naheola for­ The Nanafalia formation, which forms the base of mation. These three seem to constitute a conformable the Wilcox group in Alabama, extends from Chat- series but at plaqes may be separated from one another . tahoochee River at , Ga., as far west by local unconformities. The group is set off from as the junction of Y antley and Tickabum creeks in · the underlying rocks by a profound uncon­ but has not been recognized in formity and from the overlying Wilcox group by a less Mississippi. contains a considerable proportion of conspicuous break. hard rock resembling the buhrstone of the Tallahatta The Clayton is thickest in the neighborhood of formation (of the Claiborne), which distinguishes it , the eastern boundary of Ala­ from the other parts of the Wilcox group, and it is bama, and thins toward the west. In western Ala­ further distinguished by carrying a great profusion of bama and in Mississippi it is reduced to a thin bed of Ostrea thirsae. limestone, and over a considerable area in both States In Mississippi the position at the base of the Wilcox it is completely overlapped by the Porters Creek or group is occupied by the Ackerman formation, which Sucarnochee clay. The Porters Creek, . on the other is most extensively developed· in the middle part of hand, is thickest in Tennessee . or Mississippi and its belt ·of outcrop and pinches out near the Tennessee pinches out entirely or is completely overlapped about line on the north and near the Alabama line on the midway across Alabama. It is probable that the two east. It consists of gray, rather massive clays, some formations are partly contemporaneous, but the base of which are lignitic, and contains a peculiar . of the Clayton is doubtless older than any part of the No marine fossils have been found in it. The Acker­ Porters Creek. The N aheola formation, consisting man formation is tentatively correlated with the prevailingly of highly micaceous yellow to red sand, Nanafalia formation on the basis of its apparent extends across Alabama into Mississippi at least as far stratigraphic position, but it may be equivalent to the north as De Kalb. The Tippah sandstone member lower part of the Tuscahoma formation of Alabama. at the top of the Porters Creek clay in northern' Mis-' The Tuscahoma formation extends entirely across sissippi, is probably of the same age as the N aheola Alabama and abuts against the Holly Springs s·and formation, and it is not unlikely that the two could be at the Mississippi line. Its most characteristic united on the map by more detailed field work. It is lithologic facies are very fine laminated gray sand and perhaps significant that deposits of bauxite occur in clay and. yellow sand containing angular tilted blocks clays tentatively correlated with the N aheola forma­ of laminated clay. Both of these facies are found tion in Henry County, Ala., and also above the char­ also in the Holly Springs sand in eastern Mississippi. acteristic Porters Creek clay and beneath lignitiferous It is obvious that the Holly Springs is equivalent to beds of the Ackerman formation (Wilcox group) at at least part of the Tuscahoma, but whether or not several places in Mississippi. both formations occupy the sam~ stratigraphic interval would be difficult to prove. No marine WILCOX GROUP fossils have been found in the Holly Springs to com­ The formations of the Wilcox group in Mississippi pare with a rather characteristic fauna in the type differ much more markedly from those of the typical 1 E. A. Smith, Johnson, L. C., and Langdon, D. W., jr., Report on the geology of Wilcox of Alabama than the Midway formations in the Coastal Plain of Alabama, Alabama Geol. Survey, 1894. Mississippi differ from the Midway of Alabama. The 2 Preliminary report on iron oreS of Mississippi: Mississippi Geol. Survey Bull. 10, pp. 23-25, 1913. State line lies not far from a natural boundary or 1 Mississippi Geol. Survey Bull. 12, p. 71, 1915. transition zone which separates areas differing in type • 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, of deposists. It has been necessary to assign different 1917. CORRELATION OF EOCE.NE. FORMATIONS·, MISSISSIPPI AND ALABAMA 135 area of the Tuscahoma, and too few plant remains of loose sand. Crider 7 and Lowe 8 included in the are known from the Tuscahoma to furnish an adequate Tallahatta certain beds of quartzitic to granular sand­ basis for comparison with the large flora of the Holly stone I which are most extensively developed in At tala Springs. and adjoining counties of Mississippi but are here The Bashi formation crops out along a narrow band regarded as a local facies of the Lisbon formation. extending nearly across Alabama but apparently is Lowe divided the Tallahatta formation into two covered by an overlap of Hatchetigbee clays in parts-a lower, called the Winona sand, and an upper, western Choctaw County, near the Mississippi line. called the "Basic claystone." He regarded the sand­ In Mississippi it has been recognized" at only two stone of Attala County as equivalent to the "Basic localities near Meridian, but shells reporte.d by Hil­ elaystone," which is typical Tallahatta formation, but gard 5 from sec. 33, southwest of Marion and 2 or 3 the buhrstone of the Tallahatta can be traced be­ miles north of Meridian, although referred by him to neath the typical Winona, whieh underlies the sand­ the Claiborne, probably came from the Bashi for­ stone. The Winona is here treated as the basal mation. The characteristic feature of the Bashi is a member of the Lisbon formation. marl bed which has become locally indurated into gray In Alabama the Lisbon formation consists of two pillow-like nodules of speekled madstone or impure parts to which individual names have not been applied. limestone. The marl at most places contains a large The lower part consists chiefly of fine yellow or reddish and varied fauna of mollusks. sand and pale-green flaky clay. The upper part is Overlying the Bashi formation at Meridian and made up of calcareous clay, impure limestone, or apparently overlapping for several miles beyond the shell marl. Bashi is the Hatchetigbee formation, which is made up Lowe 9 has divided the Lisbon of Mississippi into .of brown or chocolate-colored, more or less carbo­ four members- the "Enterprise green marl" (lowest), naceous clay and gray sand. In Mississippi the ''Decatur sand," "Wautuhbee marls," and "Cock­ Hatchetigbee appears to be restricted to. Lauderdale field beds." The last is usually regarded as synony­ County, of which it covers somewhat more than 30Q mous with theYegua formation of and square miles, and the northeast corner of Clarke and is treated as an independent formation overlying County. In Alabama its belt of outcrop extends the Lis bon. The names ''Ente-rprise'' and ''Decatur'' across the State but is interrupted by overlaps of have been dropped because they had already been younger formations at the eastern extremity. Fossil used for a shale and a limestone in. and Tennes­ leaves taken from ·Hatchetigbee clay at Meridian see. correlate the formation closely with the . Grenada of The "Enterprise marl," named from a in northwestern Mississippi. 6 The Grenada formation, Clarke County, contains ___ a great deal of glauconite, which is very similar in appearance to the Hatchetigbee, which, on weathering, gives rise to highly ferruginous · has been mapped from the vicinity of Duck Hill, red beds. These red beds are perhaps the most con­ Montgomery County, Miss., northward to the Tennes­ spicuous member of the Lisbon formation and can see. line and is known to extend for a considerable easily be traced northwestward along a belt adjacent distance into Tennessee. to the outcrop of the Tallahatta formation. They CLAIBORNE GROUP appear to merge into the typical Winona sand. As the name "Enterprise" is preoccupied, the Winona The Claiborne group is divided into three forma­ sand is here redefined so as, to include the typical tions-the Tallahatta (lowest), Lisbon, and Yegua Winona sand of Montgomery County and the typical formations in Mississippi and the Tallahatta and "Enterprise marl" of Clarke County but to exclude Lisbon formations and Gosport sand in Alabama. the sands at the base of the Tallahatta formation in The Tallahatta formation extends from Grenada Lauderdale County which were erroneously correlated County, Miss., where it emerges from beneath the with the Winona by Lowe. , eastward across Mississippi and Alabama and Above the Winona red beds lie sand beds called is still recognizable across Chattahoochee River at the "Decatur sand" by Lowe. The ledges of hard Fort Gaines, Ga. The formation nearly everywhere sandstone in Attala County referred to in the discus­ is easily identifiable by its. characteristic lithology, sion of the Tallahatta formation appear to represent consisting chiefly of brittle claystone or diatomaceous an indurated facies of these sands. The name Kos­ earth and hard sandstone with angular lumps of day­ ciusko sandstone member is here proposed as a desig­ stone, but in eastern Alabama these rocks are not nation for the ledges of saccharoidal to quartzitic conspicuous and most of the formation is composed 7 Crider, A. F., Geology and mineral resources of Mississippi: U. S. Geol. Survey 1 Hilgard, E. W ., Geology and of the State of Mississippi, p. 12~ , 1860. Bull. 283, pp. 29-32, 1906. . o Berry, E. W., Geologic history indicated by the fossiliferous deposits of the s Lowe, E. N., Mississippi, its geology, geography, soil, and mineral resources: Wilcox group (Eocene) at Meridian, Miss.: U. S. Geol. Survey Prof. Paper 108, Mississippi Geol. Survey Bull. 12, pp. 72-76, 1915; Bull. 14, pp. 73-76, 1919. pp. 61-72, 1917. This correlation was suggested by Lowe in Mississippi Geol. o Lowe, E . N., Mississippi Geol. Survey Bull. 12, pp. 76-78, 1915; Bull. 14, pp. Survey Bull. 12, p. 72, 1915. 77-79, 1919. 136 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 sandstone exposed in the vicinity of Kosciusko, the 14 species of plants recorded from the Gosport sand of Attala County, Miss., and for the only 7 are included in the list of 66 from the Yegua.10 unconsolidated sands of the same age in Mississippi. The name "Decatur sand," being preoccupied, will DEPOSITS OF JACKSON AGE be dropped. Deposits of Jackson age form the upper division of The "Wautubbee marls," which lie at the top of the the Eocene. They lie conform·ably above the Clai­ Lisbon formation in Mississippi, carry the character­ borne group and below the Vicksburg group (Oligo­ istic Lisbon fauna and may be regarded as the equiv­ cene). Two formations, the typical Jackson forma­ alent of the upper or typical part of the Lisbon of tion and the .Ocala limestone, are recognized in this Alabama, which they closely resemble. For this rea­ division of the Eocene in Mississippi and Alabama, son it seems better to regard them not as a member of and they are regarded as contemporaneous.U Many the formation but as the undivided part of the forma­ fossils are common to the two formations, but each tion, and the local name is not needed. has some peculiar species. The formations differ The famous sand bed at Claiborne, Ala., which has in lithology. yielded so many beautiful. shells, is now called the The Jackson formation in Mississippi consists of Gosport sand. It is the topmost formation of the two members-the Moodys marl at the base and the Claiborne group. It is nowhere very thick and, except Yazoo clay at the top. The Moodys marl contains for its shells, is not very significant. It contains a few the celebrated shell bed from which many beautifully lenses of leaf-bearing clay which suggest correlation preserved fossils have been taken but is not otherwise with the Y egua formation. The Gosport lies con­ notable. The Yazoo clay is much thicker and more formably on the Lisbon formation and is overlain by extensive and is the horizon of cetoides, the the ScuteZZa-bearing bed at the base of the Ocala '' zeuglodon.'' The Jackson formation extends from limestone. the bluffs bordering the Yazoo Delta eastward acros~ A series of beds of carbonaceo~s sand and clay, the Mississippi and into Alabama as far as Tombigbee extension of the Y egua formation of Texas, crosses River, where it merges into the Ocala limestone. Louisiana and Mississippi, rapidly thins toward the The Ocala limestone extends eastward from Tom­ east, and probably merges with the Gosport sand in higbee River across Alabama and is widely distributed Alabama. The correlation of the Y egua with the in and southwestern . Gosport is based primarily upon the stratigraphic to Berry, E. W., The middle and upper Eocene of southeastern North position of both between the Lisbon and the Jackson, 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 for the paleontologic evidence is inadequate. Of the Mississippi and Alabama: Aead. Sci. Jour., vol. 8, pp.186-198, 1918.