54 J. J. STEVENSON — CARBONIFEROUS OF APPALACHIAN BASIN 



Feet. Inches 



4. Coal bed 1 6 



5. Fireclay and shale. , 22 



6. Coal bed, Bloomington 1 6 



7. Shale, sandstone, and conglomerate 82 



8. Coal and coaly shale 3 



9. Shales and sandstone 37 



Total 296 



A comparison of these sections shows noteworthy changes. On the 

 east side of the basin, near the northern extremity, one finds only the 

 two sandstones with intervening coal and shales, as in Broad Top ; the 

 upper sandstone there, as at Gladdens run, on the west side is very thick, 

 but at the latter locality a great mass of sandstone is inserted between 

 the coal beds, and the lower plate has become much reduced in thick- 

 ness. Doctor White's section on the Potomac, as well as that of Mr 

 O'Harra, shows the upper sandstone much reduced in thickness, the 

 lower being represented by numbers 6 and 8 of the former and by num- 

 bers 4 and 6 of the latter; but below the bottom sandstone, number 9 

 of the Gladdens Run section, there are on the easterly side a coal bed 

 and 37 feet of rock, while on the westerly side the section is increased 

 by 200 feet at the bottom, including two coal streaks separated by 195 

 feet of rock. Further reference will be made to these conditions when 

 the section has been traced southward from northwestern Pennsylvania. 



EASTERN COUNTIES OF ALLEGHENY PLATEA V 



Returning now to the north. 



Bradford county, on the New York border, is north from Sullivan. 

 The Barclay coal basin in the center of the county was studied many 

 years ago by Professor J. P. Lesley and afterward by Mr Piatt. Here 

 are two coal beds, named A and B, as in the Bernice basin of Sullivan. 

 The latter evidently belongs to the Allegheny ; the section below it is 



Feet 



Fireclay and sandstone 20 



Conglomerate 60 



Coal bed A 1 



Sandstone to red shale . . , 135 



Another small area remains in Tioga county, west from Bradford, in 

 which the Pottsville is 200 feet thick, with streaks of coal from half an 

 inch to 2 feet thick. The rock is mostly sandstone, some of it conglom- 

 erate. The succession is* 



*F. Piatt : Report of progress in Bradford and Tioga Counties (G), 1878, pp. 120, 127, 167, 178. 



