CONEMAUGH FORMATION OP WESTERN PENNSYLVANIA BASINS 179 



and its overlying coal bed or black shale are reasonably persistent. The 

 Connellsville sandstone is usually somewhat massive, though at many 

 places it becomes shaly or even is replaced by a more or less clayey shale, 

 while the Morgantown is a characteristic sandstone not far from 50 feet 

 thick. At a few feet below the last is the Elk Lick coal bed (Barton of 

 Lesley and Stevenson) and the Ames limestone, 280 to 300 feet below 

 the Pittsburg, appears almost invariably wherever its place is exposed, 

 but the Harlem coal bed is reported from only one locality in Allegheny 

 and one in Fayette. The Barton (Bakerstown) coal bed is apparently 

 constant in Fayette county at about 75 feet below the Ames, but does 

 not appear in sections within the other counties. The Cambridge lime- 

 stone does not appear in any of Stevenson's sections, and the Buffalo- 

 Cowrun sandstone, so conspicuous on the Kiskiminitas, disappears 

 rapidly southward, where one finds only shales in its place above the 

 Brush Creek (Black Fossiliferous) limestone, which rests on the Brush 

 Creek coal bed. The Mahoning varies from massive sandstone to mere 

 shale, and the Gallitzin coals, so persistent at the north, seem to be 

 absent from southern YTestmoreland and from Fayette. The red beds, 

 except that underlying the Ames limestone, become insignificant and are 

 practically unrepresented in Fayette.* 



The records of oil borings in these counties west from the narrow- 

 strip of exposed Conemaugh for the most part give little detail or are not 

 referable to any fixed datum. A record in northwestern Westmoreland 

 shows the Buffalo sandstone 70 feet thick and beginning at 110 feet 

 below the Pittsburg reds. The Mahoning, beginning 20 feet below the 

 Buffalo, is double and rests on the Upper Freeport at 595 feet below the 

 Pittsburg. The Pittsburg red is the lowest red bed, but a record near 

 Irwin, on the Pennsylvania railroad, shows three reds, 20, 32, and 5 feet 

 thick respectively, at 395, 459, and 546 feet below the Pittsburg coal bed. 

 The upper Freeport is reached at 605 feet and only shales are present 

 to 280 feet above it. A record in central Fayette county gives a thick- 

 ness of 590 feet for the Conemaugh and red shale is absent. \ 



Northern Alleghen} r , south from Butler, is between the Allegheny and 

 Ohio rivers. The exposed section extends from the Upper Freeport at 

 the north to the Pittsburg at the south. The Ames limestone is shown 

 in every township at from 280 to 300 feet below the Pittsburg coal bed 

 and the Elk Lick coal, at 25 to 35 feet above the Ames, occasionally over- 

 lies a black fossiliferous limestone which may be the equivalent of the 



* J. J. Stevenson : (K K), pp. 64, 74, 75, 137, 141, 171, 172, 182, 274, 316, 318, 348. 

 | J. F. Carll : Oil and Gas Report for 1889, pp. 214, 221, 226, 320-322. 

 I. C. White : Geology of West Virginia, vol. \a, p. 115. 



