

CONEMAUGH FORMATION OF WESTERN PENNSYLVANIA BASINS 177 



tion. The Cowrun sandstone, between it and the Cambridge limestone, 

 is represented by shale in Butler county, though it is a well marked sand- 

 stone in Allegheny county. The Ames limestone is always seen where 

 its horizon is exposed, as are also its underlying red shales, but the Har- 

 lem coal bed seems to be wholly wanting. The Elk Lick coal bed was 

 seen in the only townships in which its horizon is reached." 



In southeastern Lawrence, west from Butler, a double coal bed is ap- 

 parently persistent at 55 to 65 feet above the Upper Freeport limestone 

 and overlying a fireclay containing much calcareous iron ore which at 

 one locality is limestone, representing the Mahoning. In one place it is 

 overlain by 20 feet of shale, but in another by a massive conglomerate.! 



Beaver county, extending to the Ohio line, is south from Lawrence and 

 west from Butler and Allegheny. Extensive erosion by large streams 

 has removed the Conemaugh from much of the county north from the 

 Ohio river, so that in the central portion that formation occurs in some- 

 what widely separated areas. The Elk Lick horizon is reached in a few 

 places and the coal bed is shown. The Ames limestone and the Pitts- 

 burg reds are persistent, but the Harlem, Barton, and Anderson coal 

 beds are apparently absent throughout. The place of the Cambridge 

 limestone is rarely exposed, but that bed is present on both sides of the 

 county at about 120 feet below the Ames and 60 to 65 feet above the 

 Brush Creek. The Buffalo sandstone varies from coarse to fine sand- 

 stone or sandy shale and at one locality it is replaced by variegated shale. 



In the northern tier of townships one finds at 6 miles southwest from 

 the Lawrence County exposures, already referred to, a coal bed, evi- 

 dently the Brush Creek, at 80 to 90 feet above the Upper Freeport and 

 12 feet below the decomposed Brush Creek limestone. Like that in 

 Lawrence, this is a double bed, the upper portion more or less resembling 

 cannel. The interval in Lawrence is 55 to 65 feet. Farther west a coal 

 blossom appears on the hilltops at 58 to 70 feet above the Upper Free- 

 port, with at 3 to 4 feet below it a slabby limestone, while still farther 

 west, near the Ohio line, the interval is 60 to 65 feet. Four miles west, 

 in Columbiana county of Ohio, Doctor White finds a coal at 50 feet, the 

 interval being, as in northwest Beaver, concealed. This is the Coal 7, 

 or the Groff vein, of northeast Ohio. Farther south in Beaver county 

 one finds on the east or Butler County side the Brush Creek coal bed, 

 12 feet below its limestone, 185 to 207 feet below the Ames limestone 

 and about 90 feet above the Upper Freeport, with a thin Gallitzin bed at 



* I. C. White: (Q), pp. 24, 73-74, 76, 79, 80, 84, 87, 89, 91, 96, 99, 101-103, 106, 115, 

 123, 128-129, 135-136. 



tl. C. White: (Q 2), pp. 76, 79, 80, 81, 82. 



XV — Bull. Geol. Soc. Am., Vol. 17. 1905 



