172 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



to the Upper Freeport. The Barton is 134 feet above the Brush Creek, 

 which is 78 feet above the Upper Freeport. Here the Buffalo sandstone 

 overlies the Brush Creek limestone directly and there is no trace of the 

 Cambridge. Another boring, barely a mile away, shows the Barton only 

 86 feet above the bottom of the Black fossiliferous shales, which are 104 

 feet above the Upper Freeport. There also the coarse Buffalo sandstone 

 overlies the black shale; but at 5 miles northwest, in the Third basin, 

 the interval from Brush Creek limestone to the Upper Freeport is but 50 

 feet. In all of the cores that limestone and its shales are characteristic, 

 both of them black and richly charged with fossils. 



The Mahoning is very thick in the northern part of the basin, but be- 

 comes thinner southward, while the interval between Brush Creek and 

 Ames limestones, small at the north, increases southward, so that toward 

 the West Virginia line the section becomes comparable with those in the 

 Third basin and beyond. 



Measurements by Doctor White at Newburg, 10 miles south from 

 Masontown, show the interval above the Ames to the Pittsburg thicker 

 than in Westmoreland county. The Elk Lick coal bed is at 259 feet 

 below the Pittsburg and the Ames is represented by shales at 344 to 357, 

 with the Harlem coal bed at 357.* 



In Preston county the second basin becomes continuous with the third. 



WESTERN BITUMINOUS BASINS OF PENNSYLVANIA 



The Mahoning is present in small patches within southern Elk county, 

 where it is in two more or less shaly divisions separated by a thin Gallit- 

 zin coal bed.f 



Mr Piatt's report shows scattered areas of Conemaugh in Jefferson 

 county, but except in the eastern portion, near Chestnut ridge, the thick- 

 ness remaining rarely exceeds 100 feet. In Clarion, west from Jefferson, 

 some insignificant fragments remain, but the exposures are too imperfect 

 for measurement. 



The information respecting eastern Jefferson is indefinite, as the ex- 

 posures seem to be very poor. Coal beds were seen in the east-central 

 part of the county at 85 and 105 feet above the Upper Freeport, while on 

 the Indiana border at the south are beds at 135, 310, and 385 feet, the 

 last one 15 feet below an argillaceous limestone, 403 feet above the 

 Upper Freeport. Two beds of red shale, 2 and 6 feet respectively, are at 

 185 and 222 feet, but the whole column is without notable sandstone ex- 

 cept at the bottom, where the "Mahoning" is a massive rock. This 



* I. C. White : Geology of West Virginia, vol. ii, pp. 233, 269, 310. 

 f C. A. Ashburner: (R R), pp. 209, 227. 



