EASTERN COUNTIES OF ALLEGHENY PLATEAU 59 



of about 200 feet on Haskins run, where coal is present in the upper 

 portion.* 



Westmoreland and Fayette counties are west from Somerset, the latter 

 extending to the West Virginia-Maryland line. The great axes of Laurel 

 hill and Chestnut hill increase southward, so that in the eastern portion 

 of these counties the Pottsville is reached in numerous gaps, and one can 

 trace the changes from the Conemaugh to the state line. 



In Laurel hill, which separates these counties from Somerset, the sand- 

 stone mass, about 150 feet thick, seen on the Conemaugh, may represent 

 the Homewood and Connoquenessing sandstones of White, the Johnsons 

 run and Kinzua sandstones of Ashburner. The Sharon shales and coals 

 underlying this are not shown on the Conemaugh, but within a few 

 miles southward an exposure of 24 feet shows 2 to 4 inches of coal at 10 

 feet below the sandstone, associated with the iron ores, which, in these 

 counties, are characteristic of this lower division. Farther south the 

 sandstone mass is but 100 feet thick and not very coarse. In the Youg- 

 hiogheny gap the sandstone is about 100 feet, but distinctly separated 

 into the Homewood (Piedmont of Maryland) and the Connoquenessing 

 sandstones, with a Mercer coal bed, the Mount Savage of Maryland, be- 

 tween them. The Homewood sandstone is about 30 feet thick and much 

 of it is pebbty, in this respect differing little from the Connoquenessing. 

 The coal bed rarely exceeds 15 inches and often is found distributed in 

 fragments through the lower part of the overlying sandstone. The lower 

 or Sharon division is shown in railway cuts below Ohiopyle on the 

 Youghiogheny, where it consists of shales, sandstones, and thin coals. 

 The thickness varies greatly, chiefly in the shales, but the extreme is 

 approximately 140 feet. The sandstone beds are at 40 and 45 feet re- 

 spectively, and show comparatively little variation. Three thin coal 

 beds were seen here, the lowest at 140 feet below the Connoquenessing. 

 A fourth evidently underlay the sandstone, as its fragments are distrib- 

 uted through the lower portion of that rock. There is nothing here that 

 can be identified directly with the Sharon sandstone, but the great thick- 

 ness below the Connoquenessing suggests that some portion may be con- 

 temporaneous with that deposit.f 



Under Chestnut Hill the Pottsville quickly regains its character south 

 from the Conemaugh, for in the Loyalhanna gap it shows 50 feet of 

 sandstone resting on red shales, but without coal. The same thickness 

 of sandstone was seen in the southern part of Westmoreland county, 

 where the lower or Sharon division is about 90 feet thick. The Mount 

 Savage coal bed is here, and at least two thin beds are in the Sharon 



* W. G. Piatt : Cambria and Somerset Dist. II (H3), 1878, pp. 141, 146. 

 t J. J. Stevenson (K3), pp. 82, 101, 134, 177. 



