52 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



shale. The roof division of the Pittsburg, rarely thicker than 3 inches 

 north from the railroad, increases southwardly to 6 inches and 1 foot, 

 and at 4 miles the bed shows : 



Roof, 3-4 feet 4 inches ; clay 1 to 18 inches ; Main coal, 7 feet 9 inches, 



the roof consisting of coal and clay interleaved. Eight miles farther 

 south, near Mount Pleasant, the Waynesburg, underlying its sandstone, 

 is 5 feet thick and 66 feet above the Uniontown coal bed. Here one 

 sees the Little Wa5mesburg coal bed; the Waynesburg, Uniontown, and 

 Benwood limestones are present and thick, the last two being separated 

 by 30 feet of sandstone. The Lower Sewickley coal bed, underlying the 

 Sewickley sandstone, is only 18 inches thick and 40 feet above the Eed- 

 stone, which shows 2 to 4 feet of coal and is somewhat more than 80 

 feet above the Pittsburg.* 



There are few exposures above the Pittsburg in northern Fayette 

 county and erosion by tributaries of Jacobs creek and Youghiogheny 

 river has removed much of the Monongahela. The conditions south 

 from the Youghiogheny are little better, but records of shafts and bor- 

 ings are numerous and show notable variation in the lower part of the 

 section, quite like those of the Potomac areas and the Salisbury basin. 



The Waynesburg coal bed is exposed near Mount Braddock, about 6 

 miles from the river, where it is 4 feet thick and 71 feet 6 inches above 

 the Uniontown coal bed, as measured in a boring there. Pour miles 

 farther south the interval is 77 feet. The Little Wa5Tiesburg is present 

 at both localities, 31 and 25 feet below the Waynesburg and resting on 

 the Waynesburg limestone. The Waynesburg and Uniontown lime- 

 stones are persistent, though thin, to the last exposure of their horizons, 

 and in the southern part of the basin the Uniontown coal bed underlies 

 an impure limestone containing many small lamellibranchiates of un- 

 determined relations. The lower part of the column is shown in the 

 Leisenring shaft, 3 or 4 miles south from Connellsville, an exposed sec- 

 tion at 3 miles southeast from Connellsville, and at the Leith shaft, 13 

 miles south. The measurements are: 



Feet Inches Feet Inches Feet Inches 



1. Limestone 29 ^ r 25 9 



2. Shale 3 L 52 J 21 3 



S.Limestone 26 OJ | 22 6 



4. Shale or clay 5 15 9 6 



5. Upper Sewickley coal bed 2 3 3 5 3 



6. Sewickley sandstone or shale. . . 30 25 



* J. J. Stevenson: (K 2), pp. 266, 267, 271, 272, 273, 274, 279, 281, 283, 284. 

 W. G. Piatt: Indiana county (H 4), p. 157. 



