CONEMAUGH FORMATION OF WESTERN PENNSYLVANIA BASINS 181 



whole section changes and neither limestone nor red shale appears. The 

 Ames limestone, 280 to 300 feet below the Pittsburg, is constant and at 

 many places is accompanied by the Harlem coal bed. In the Painter 

 well, on the Monongahela river above Pittsburg, the Cambridge lime- 

 stone is at about 420 feet below the Pittsburg and a coal, probably the 

 Gallitzin, is at 528. The Mahoning is represented by shale.* 



In Washington county one finds at the extreme north the Elk Lick 

 coal bed, 10 feet below the 90-foot Morgantown sandstone or 260 feet 

 below the Pittsburg and 35 feet above the Ames limestone, which rests 

 on the Harlem coal. The Little Pittsburg coals are wanting, but there 

 are two persistent limestones within 30 feet. On the Monongahela 3 

 limestones occur in this interval and the Little Pittsburg coal is repre- 

 sented by black shale. 



The records of oil borings show irregularity in the Conemaugh section. 

 The interval from the Pittsburg coal bed to the Mahoning varies from 

 463 to 488 feet, that rock in some cases being almost continuous above 

 with the Buffalo. Both divisions of the Mahoning are distinct and are 

 usually sandstone, though varying greatly in thickness; occasionally, 

 however, one or the other is replaced by shales, and changes of this kind 

 are frequently abrupt. One of two wells near the borough of Washing- 

 ton shows the Upper Mahoning all sandstone, but in the other it is all 

 shale. 



The Buffalo sandstone is represented by shale at McDonald; at other 

 localities it is distinct as a sandstone, but very variable. In one well at 

 Washington it begins at 413 feet, evidently replacing the Cambridge 

 limestone, and is separated by but 4 feet of shale from the Mahoning 

 at 488, thus giving an almost continuous mass of sandstone, 107 feet 

 thick; but in the other well it begins at 428, is only 20 feet thick, and is 

 separated by 100 feet of "slate and shells" from the Lower Mahoning. 

 At Beallsville, east from Washington, it begins at 448 and is 25 feet 

 thick. The sandstones above the Buffalo are equally irregular; the 

 Morgantown horizon is sufficiently well marked, but the other beds, some 

 of them very thick, can not be correlated with airy at exposed sections. 

 No coal is recorded anywhere except at McDonald, where the Little 

 Clarksburg is at 175 and a Gallitzin bed at 501 feet below the Pittsburg. 



The red beds are important members of the formation, though they 

 are extremely variable. There are three horizons, 129 to 174, 236 to 

 310, and 367 to 413, within which these beds occur in almost all of the 



*J. J. Stevenson: (K), pp. 296, 298, 324-326, 306-309, 310, 314. 

 I. C. White : Geology of West Virginia, vol. ia, pp. 101-102. 



