76 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



(b) THE WESTERN PART OF THE SOUTHERN SUBPROVINCE. 



The upper Pennsylvanian and Permo-Carboniferous of Pennsylvania 

 and West Virginia is continued almost without break into Ohio and Ken- 

 tucky. A detailed summary of the Conemaugh formations in Ohio was 

 quoted from Condit in Publication No. 207 of the Carnegie Institution, 

 pages 81 to 84, and need not be repeated here. It is noted, page 83 of that 

 publication, that it is evident from Condit's description that conditions in 

 Ohio during Conemaugh time were in many regards very similar to those 

 obtaining (at a later date?) in the Plains Province. Condit says: 1 



"The Permian of the West, characterized by bright colors and beds of gypsum, 

 is a still more striking illustration of this kind [beds deposited as deltas in a 

 semiarid climate]. While evidence of such pronounced aridity is lacking in the 

 Permian (Dunkard) beds of the Appalachian basin, still it is evident that condi- 

 tions were somewhat similar. It is believed that the appearance of the red color 

 in the Conemaugh marks the beginning of the Permian. In southern Ohio, 

 where the Monongahela coals and limestones are scantily developed, the red 

 beds are practically continuous from the Conemaugh through the Monongahela, 

 uniting with those of the Dunkard." 



The Dunkard formation in Ohio according to Stauffer 2 is represented 

 by only the thin edge left by the erosion, of the much more extensive bed 

 which lies to the east. 



"At the northern end of the Ohio portion of the Dunkard basin there is no 

 appreciable break between the Monongahela and the overlying Dunkard series. 

 From the stratigraphic relations the basal plant beds (Cassville) ought therefore 

 to continue the same flora that flourished during the formation of the preceding 

 Waynesburg coal bed, but apparently such is not the case. Over the southern 

 half of the basin, however, the Waynesburg sandstone usually rests directly on 

 the Monongahela with marked unconformity, the Cassville, the Waynesburg 

 coal, and a portion of the underlying shales usually being absent. Uncon- 

 formities in a series of rocks, such as the Dunkard, probably do not have any 

 very great significance; in fact, they occur at several horizons within the series; 

 but the development of the coarse, massive Waynesburg sandstone, often a true 

 conglomerate, over much of the unconformity between Monongahela and 

 Dunkard, may be indicative of changed conditions. 



"* * * This division of the Dunkard into two formations is very arbitrary, 

 as the stratigraphical or even the lithological break at the horizon used is not pro- 

 nounced. It does, however, mark the highest level at which marine or brackish- 

 water fossils were found and probably represents the approximate close of the 

 oscillations between land and marine conditions, and introduces the purely land 

 and fresh-water deposits in the Dunkard basin. * * * 



"A large part of the Dunkard of Ohio is to be classed as 'red beds,' although 

 the Monongahela series and even the Conemaugh are not without their red shales, 



1 Condit, D. D., The Conemaugh Formation in Ohio, Bulletin Ohio Geological Survey, 



vol. 17, p. 259, 1912. 



2 Stauffer, C. R., Divisions and Correlations of the Dunkard Series in Ohio, Bull. Geol. 



Soc. Amer., vol. 27, p. 86, 1915. 



