94 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



Feet. Inches. 



6. Fireclay, green shale, sandstone 7 6 



7. Hard pebbly sandstone [Freeport] 76 4 



8. Black shale, Middle Kittanning coal bed 8 5 



9. Slate, shale, fireclay 61 8 



10. Gray sandstone 6 1 



11. Slate and coal 1 



12. Shale 7 6 



13. Clarion coal bed [Brookville] 9 1 



14. Fireclay 12 10 



to the Pottsville sandstone. The Upper Freeport is 86 feet below the 

 Brush Creek limestone, which is embedded in black fossiliferous shale 

 immediately overlying the Brush Creek coal bed. The interval from 

 Upper Freeport to the Middle Kittanning is 146 feet, and to the top of the 

 fireclay which underlies the place of the Lower Kittanning 199 feet, 

 almost the same as in southern Fayette. The Brookville coal bed is 

 worthless, in two nearly equal benches of slaty coal, separated by 6 feet 

 5 inches of fireclay. The Lower Freeport is a double bed and the Upper 

 Freeport is in 13 layers of coal, bone, and slate. 



At a few miles farther south this Second basin, owing to the decreasing 

 strength of Chestnut hill, becomes continuous with the western basins, 

 and it will be described in connection with the West Virginia area.* 



WESTERN BASINS OF PENNSYLVANIA 



The region west from Chestnut Hill anticline to the Ohio line may be 

 considered as one, there being no very strongly marked divisions. 



A small area of Coal Measures remains in Tioga and Potter counties 

 near the line of New York, in which the upper part of the section may 

 belong to the Allegheny, but, as Mr David White has shown, the greater 

 part belongs to the Pottsville, according to the testimony of the plant 

 remains. The distance from other areas is too great to admit of correla- 

 tion on any other basis. 



Some isolated patches remain in McKean county, west from Potter, the 

 most northerly being about 10 miles north from the line of Elk county, 

 where the section reaches upward to the Middle Kittanning coal bed. 

 The persistent coals are those named Dagus and Clermont, which Mr 

 Ashburner identifies with the Lower Kittanning and Clarion. Between 

 them is the Vanport (Ferriferous) limestone at 8 to 30 feet below the 

 Dagus coal, wanting, however, at the most northerly exposure as well as 

 in the southeastern part of the county, and, where present, somewhat im- 

 pure, though at times 8 feet thick. The interval between Dagus and 



* I. C. White : Geology of West Virginia, vol. ii, pp. 311, 344. 



