204 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



It seems probable also that Stevenson erred in his determination 

 within Westmoreland county, and that he referred too much to the 

 Sharon horizon, his conclusions being at variance with the results of 

 borings in the Monongahela valley, within both Westmoreland and 

 Fayette counties. This matter will be examined carefully on the ground 

 prior to preparation of the discussion of the geographical conditions. 



In West Virginia the Lower Pottsville reappears at some distance south 

 from the line of the Baltimore and. Ohio railroad, and, as has been seen 

 in the study of oil well records, new members are added below toward 

 the south, though with irregularities, which possess much interest in 

 another connection. Southward from the Kanawha the section approx- 

 imates more closely to that along the eastern border, until in Kentucky 

 and northern Tennessee it is practically the same. The Upper Pottsville 

 varies in much the same way, increasing slowly throughout, until be- 

 yond the Kanawha one finds the great increase in the lower part of the 

 column with less notable increase in the upper. 



Further reference to these conditions is unnecessary in this connection. 

 In a later portion of this work the detailed discussion will be given. 



The distinction between Upper and Lower Pottsville is very marked 

 in the greater part of West Virginia, Virginia, and northern Tennessee, 

 on the eastern side of the basin, as well as in much of Ohio ; in Ken- 

 tucky and northern Tennessee along the western side. It is necessary 

 to designate them by special terms. The only name which has been 

 applied to the Upper Pottsville, as defined in this paper, is that of 

 Beaver series, used by J. P. Lesley in 1878 ; but several correspondents 

 in referring to the formation have spoken of it as the Mercer, a good term. 

 Kanawha of Campbell can not be employed, as it embraces important 

 horizons of the Allegheny and its use would lead to confusion. Several 

 terms have been applied to the Lower Pottsville, in whole or in part. 

 Lee of Campbell, in southwest Virginia, does not include the highest 

 members in the locality where the name was first applied. The earlier 

 name, Rockcastle of Crandall, was given in southern Kentucky, where 

 the lowest members are wanting; but in the same report it was applied 

 to the Pine Mountain region, where the section is practically complete. 



Synonymy 



The synonyms and distribution of the more important horizons are 



Beaver. 



Homewood sandstone Homewood of I. C.White, Johnson Run of Ashburner, 



(I. C. White.) Piedmont of Ashburner and Stevenson in Pennsyl- 



vania; Piedmont and Homewood of I. C.White and 



