270 D. WHITE — DEPOSITION OF APPALACHIAN POTTSVILLE 



stone are found to contain plants of types requiring the reference of the 

 terranes'to the lower portion of the Mississippian .* It is difficult to 

 conclude how far this condition obtains, but it is probable that the 

 Sharon conglomerate is wanting from a large part of the bituminous 

 area of Pennsylvania/)" To a certain extent the sections to the south 

 and west of the Allegheny valley have been interpreted in accordance 

 with the Red Bank sections, but in the more remote instances the meas- 

 urements here given are subject to revision. 



In West Virginia and Kentucky the upper boundary of the Pottsville 

 is drawn so as to include the Coalburg coal, whose flora at all points 

 furnishing plants is found to fall within the Upper Pottsville. Farther 

 northeast, in northern West Virginia, the line is provisionally drawn at 

 the Roaring Creek sandstone. The Pottsville-Allegheny boundary is 

 not yet closely drawn in the counties of southwest Virginia and northern 

 Tennessee ; but the flora in the lower part of the Wise formation J is so 

 old as to render it probable that the entire formation is Pottsville, to 

 which a part of the Harlan is perhaps to be added. I 



In the Middlesboro region the highest beds of the Cumberland Valley 

 syncline do not appear to reach the Allegheny, while in the Briceville 

 quadrangle the highest plant beds, less than 250 feet below the topmost 

 point of the Anderson formation, show a mingling of types which in a less 

 expanded series would indicate proximity to the base of the Allegheny, 

 but which in this region may be hundreds of feet from the boundary. 

 South of the Briceville quadrangle the remaining terranes of the Coal 

 Measures do not reach to the top of the Pottsville, though a thickness 

 of over 5,500 feet of beds is reported in the Coosa and Cahaba basins. 



The floras of the Alabama coal fields are but partially studied, II but it 

 will suffice in this connection to state that the plants of the highest beds, 

 the Montevallo group in the Cahaba field and the Brookwood in the 

 Warrior field, indicate a stage of the Pottsville that is probably below the 

 Sharon conglomerate and certainly older than the coals of the Kana- 

 wha. In contouring those portions of the coal field in southern Ten- 

 nessee and in Alabama, no allowance is made for the higher Pottsville 



*See Science, vol. xvii, 1903, p. 942. The inclusion of a portion of the Pottsville of Lesley and 

 I. C. White in the Lower Carboniferous was foreshadowed locally by W. G. Piatt (Rept. of Progress, 

 Second Geo!. Survey of Pennsylvania, H 5 , p. 144; see also p. xv), who referred the sandstone be- 

 low the silicious limestone on Mahoning creek to the Pocono. 



tThe writer ventures to suggest, tentatively, that the Lower Connoquenessing, which appears 

 to rest unconformably on the Lower Carboniferous in this region, has in its eastward extension 

 probably been mistaken for the Sharon, and that the coal generally regarded as Sharon along the 

 Allegheny front and in the northeastern counties represents the Quakertown. 



\ For descriptions of the Wise and Harlan formations, see Geologic Atlas of the United States : 

 Bristol and Estillville folios, by.M. R. Campbell. 



g Paleontological material is lacking for the determination of this point. 



|| See Science, n. s., vol. iii, 189(1, p. 535. 



