$8 J. J. STEVENSON — CARBONIFEROUS OF APPALACHIAN BASIN 



Massive in the northern part of the county, they become shaly in other 

 portions. At times they form a continuous mass of sandstone, and in 

 southeastern Lawrence the Upper Connoquenessing is continuous with 

 the Homewood sandstone, 130 feet thick. The Quakertown shales are 

 sandy. Their coal is of workable thickness at Quakertown, on the Ohio 

 line. Elsewhere it is thin, and in the southeastern part of the county it 

 is represented only by carbonaceous shale. 



The Sharon shales, with their iron, persist, and where exposed rest 

 upon the Shenango shales; but in the southern part of the county two 

 well records show a sandstone below them which may represent the 

 Sharon. The Sharon coal bed disappears southward in the northern 

 part of the county, but at many localities elsewhere its horizon is marked 

 by black shales, occasionally containing coaly streaks.* 



In Beaver county, south from Lawrence along the Ohio line, the 

 Pottsville passes below cover at about 6 miles from the Lawrence border. 



The notable feature is the extraordinary thickening of the Homewood 

 sandstone at about 4 miles south from Lawrence county. At the north- 

 ern line of Beaver the mass is of moderate thickness and is overlain by 

 shales of the Allegheny formation, which include some thin coal beds ; 

 but near Homewood and thence southward for more than a mile it is 

 from 150 to 160 feet thick, the increase being at the expense of the 

 overlying beds, which it has replaced up to the Ferriferous limestone. 

 Farther south the thickness diminishes, becoming only 60 feet within 

 2 miles, and the rock passes under cover along the Beaver river near 

 New Brighton. 



The Tionesta coal bed is present directly under the Homewood sand- 

 stone. The Upper Mercer coal bed and limestone are apparentl} 7 " absent 

 throughout, but the Lower Mercer coal bed and limestone are present 

 in the northern part of the county, though they evidently disappear 

 within a short distance southward. The Connoquenessing sandstones 

 appear to persist, being reported in the oil-well records as far as the 

 southern border of the county, and the Quakertown shales are sandy. 

 The Sharon coal bed, as well as the Sharon sandstone, is absent, but the 

 plant-bearing shales marking the place of the coal persist.! 



There remains a group of counties east from those along the Ohio 

 line. Venango county, south from Warren and east from Crawford and 

 Lawrence, evidently shows conditions similar to those of Crawford. The 

 geological investigations in this county were made with especial refer- 

 ence to the petroleum interests, and few details respecting the Pottsville 

 are given in the report, as it contains little of economic value; but 



*I. C White : Geology of Lawrence County (Q 2), 1879, pp. 52-70. 



fl. C. White : Report of Progress in Beaver River District (Q), 1878, pp. 65-72. 





