72 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



The Johnstown cement limestone of W. G. Piatt, Upper Kittanning of 

 the Ligonier Valley report, is confined practically to the first and second 

 bituminous basins of Pennsylvania, being found in only two or possibly 

 three counties west from Chestnut hill in that state. It was confounded 

 for a long time with the Vanport limestone, an error which led to con- 

 fusion in those basins, where the lower limestone is wanting. It is non- 

 fossiliferous. 



The Middle Kittanning coal bed. In Pennsylvania, Middle Kittanning, Kittan- 

 H. M. Chance, 1879. ning, Lower Kittanning of Ligonier valley, 



Darlington of Mercer and Lawrence; in 

 southern Ohio, No. 6, "Great vein," Nelson- 

 ville, Hocking valley, Sheridan, etcetera ; in 

 Kentucky, Coal 7. 



For the most part this is unimportant in Pennsylvania, though it is 

 widespread and occasionally, like the Upper Kittanning and the Lower 

 Freeport, carries a deposit of cannel which locally is of some importance ; 

 but in Ohio it attains vast importance within the Hocking Valley coal 

 field. In much of Ohio it is roofed by a black shale carrying a rich 

 marine fauna. The overlying shale has yielded an abundant flora in 

 western Pennsylvania. 



The Lower Kittanning coal bed. In Pennsylvania, Kittanning, Lower Kittan- 

 F. Piatt, 1877. ning, Barnett of Broad Top, Clarion of 



Ligonier valley, Dagus of McKean and Elk ; 

 in Ohio, Leetonia, "Clay vein," "Creek 

 vein" No. 5 of Columbiana and Jefferson, 

 Newcastle in southern Ohio; in Kentucky, 

 Coal 6 ; in West Virginia, Kittanning ; Kit- 

 tanning of Lesley, 1856. 



This coal bed is equally persistent with the Upper Freeport and shows 

 similar variations in commercial importance. It is best on the eastern 

 side of the basin, but occasionally it is good enough and thick enough in 

 Ohio to be mined ; it is unimportant for the most part in Kentucky. The 

 interval between Middle and Lower Kittanning often disappears in 

 Maryland and eastern West Virginia, so that both beds can be mined as 

 one. The underlying clay is of great industrial importance in western 

 Pennsylvania and in much of Ohio. The interval between Upper Free- 

 port and Lower Kittanning shows no abrupt variations in most of Penn- 

 sylvania, though within the same area the intervals between intervening 

 beds exhibit perplexing variations. The interval between the Lower Kit- 

 tanning and the Vanport limestone below is one of the most variable in 

 the whole section. When large, it often contains the Kittanning sand- 

 stone, whose changes in character are as marked as those of the Freeport 

 and Butler. 



