CHAPTER VIII. 



STRATIGRAPHY THE ALLEGHENY SERIES. 



GENERAL DESCRIPTION AND SECTION. 



The Allegheny Series of the Pennsylvania!! Rocks, de- 

 scribed and named by the First Geological Survey of Pennsyl- 

 vania from its occurrence along the river of the same name 

 in that State, outcrops over a considerable area in Collins 

 Settlement District, Lewis, its areal extent being shown on 

 Map II by a colored symbol. This series, which begins at 

 the top with the Upper Freeport Coal horizon and extends 

 downward to the top of the Homewood Sandstone of the 

 Pottsville, having an average thickness of about 250 feet, is 

 composed largely of gray sandstones and gray, sandy shales, 

 making an entirely different type of soil from that originating 

 from the Conemaugh beds described in the previous Chapter. 

 The series contains no limestones of importance, but has three 

 coal seams of minable thickness, one of which is persistent 

 throughout the region of its outcrop. The fire clays that are 

 of considerable economic value in the northern counties, are 

 almost wholly lacking in Lewis. 



The following general section, compiled from the sections 

 published in Chapter IV, as well as from other detailed ob- 

 servations, shows the Allegheny Series for this area : 



General Section of the Allegheny Series for Lewis and Gilmer. 



Thickness. Total. 



Feet. Feet. 



Coal, Upper Freeport 1 1 



Shale 8 9 



Limestone, Upper Freeport 1 10 



Shale 5 15 



Sandstone, massive, gray, Upper Freeport 30 45 



Shale, sandy 4 49 



Coal, Lower Freeport 1 50 



