THE MIDWAYC?) FLORA FROM EAIU.K, TEXAS. 



MIDWAY FORMATION. 



STUDY OF THE STRATIGRAPHY. 



Interest in the study of the Midway foniiti- 

 tion has been confined wholly to its geology and 

 palcozoology. I know of no mention of fossil 

 plants, aside from lignitic material, except 

 Glenn's ' statement of their occurrence in a cut 

 on tlie Southern Railway just east of Middle- 

 ton, Tenn. 



With regard to the nomenclature of tlie Mid- 

 way, it is to be noted that Jlilgard - in 1860 

 divided the Tertiary of that State into Great 

 Northern Lignitic, Claiborne, Jackson, and 

 Vicksburg, the first including as its basal mem- 

 ber the so-caJled Flatwoods clay. Li 1864 Saf- 

 ford •■' proposed the name Porters Creek group 

 for the basal Eocene in west Tennessee. In 

 1887 Smith and Johnson'' differentiated in 

 southern Alabama three formations, which 

 they named Midway (basal deposits of Mid- 

 way group, later called Clayton limestone), 

 Black Bluff ( =Sucarnoochee), and Naheola 

 or Matthews Landing, retaining them as 

 members of Hilgard's Lignitic group, the Mid- 

 way taking its name from Midway Landing 

 on the west bank of Alabama River in Wilcox 

 County, Ala. In 1894 the paleozoologic studies 

 of Harris ^ led him to propose the term Midway 

 stag(' for these and synchronous deposits in 

 adjoining States. These constitute tlie Mid- 

 wayan stage of Call's correlation paper " ])uh- 

 lished two years later. The dclailed liislory of 

 the study of these deposits, both before and sub- 

 sequent to this date, is not within the province 

 of this sketch of the nomenclature. 



Tlie Midway is singularly poor in remains of 

 land plants, which abound in subsequent 

 Eocene deposits, especially those of tlie Wilcox 

 and C'laiborne groups, so that the study of the 



' Olcnn, L. C, U. S. Geol. Survey Water-Supply Paper 164, p. 32, 1906. 



' Hllgard, E. W., Report on the Reolocy and agrioullure of Mississipjii, 

 pp. 110-111, iK(;n. 



'SulTord, J. M., Am, Jour. Sci., 2d ser., vol. 37, p. 3(iS, 1801. 



•Smith, K. A., and Johnson, L. C, U. S. Geol. Survey Hull. 4.!, p. is, 

 18X7. 



' Harris, O. D., Arkansas Geol. Survey Ann. Uept. for 1892, vol. 2, 

 pp. X, 0, 22, 1K94: Bull. Am. Paleontology, vol. I, pp. 11-13, 1S96. 



« IJall, VV. II., U. S. Geol. Survey Eighteenth Ann. Rcpt., pt, 2, table 

 opp. p. 334, 1S9S. 



8 



flora (•ontrit)iites but little to the elucidation of 

 the Midway dei^osits, much less than it does to 

 any other Tertiary horizon of southeastern 



Nortli .-Vnierica. 



CHARACTER AND DISTRIBUTION. 



Except for tiiin exposures of the Black Mingo 

 formation carrying Midway invertebrates in 

 the Santee <irainage basin of South Carolina, 

 the easternmost known ex[)osures of Midway 

 strata occur in Houston ('ounty, in central 

 Georgia. To the east they are buried by 

 the transgressions of both the Claiborne and 

 Jackson. To the west they outcrop as a 

 narrow belt of sands, clays, and Imiestones esti- 

 mated to be more than 400 feet thick. Along 

 the Chattahoochee the Midway is represented 

 by about 200 feet of calcareous sands and linu^- 

 stones. These strata form a continuous belt 

 across Alabama, where the Midway becomes a 

 group, diirercntiated into three formations — 

 the Clayton limestone, Sucarnoochee day, and 

 Naheola formation. The first is an impure 

 limestone, the second a l)rowii or black clay, 

 and the third a sandy glauconitic day. To- 

 ward the western border of xUabama the strike 

 of the Midway deposits swings around toward 

 the northwest. It becomes almost due north 

 soon after entering Mississippi, and crosses 

 the northeastern part of that State, where the 

 deposits art! litliologicall^' bipartite instead of 

 tripartite, consisting of limestones below and 

 clays above. The days form the so-called 

 Flatwoods, and to them has been applied the 

 name Porters Creek day, used by Safl'ord in 

 Tennessee. They are supposed to rejiresent 

 the Siicarnoocliee and Naheola formations of 

 western .\labania. Tlu^ strike of tlie beds of 

 Midway age becomes east of north across west- 

 ern Tennessee, where they have also b<>en 

 called Porters Creek clay. They consist of 

 more than 200 feet of dark clays, with some 

 limestones and glauconitic sands. In Marshall 

 County, Ky., the belt of outcro])piiig deposits 

 of Midway age, which is 10 to 12 miles in 

 width, turns westward, crossing Ohio River 

 into Puhuski County, 111. It is cut out by the 



