13. EYE TOWNSHIP. F\ 311 



The ridge of this mountain differs in a striking manner 

 from that of Tuscarora. The latter exhibits an even, un- 

 broken line against the sky. The former consists of a suc- 

 cession of hummocks with lower places, or notches, between 

 them. 



It consists of two vertical walls, the Medina sandstone 

 and the Iron sandstone of the Clinton group, neither of 

 which is very massive. Between these retaining walls is 

 confined about 500 feet of soft material — the Clinton lower 

 green shale. Consequently the Blue mountain affords in 

 many places a broad Hat top of cultivable land, as at 

 Sterrett's gap, buttressed on the north by the thin Iron 

 sandstone, and on the south by the thicker but not massive 

 Medina sandstone. Such a shale-mass forms a good gather- 

 ing ground for water which finds its way out through or over 

 the retaining sandstone walls, and has therefore cut them 

 down in man}' places, in some so low as to afford gaps over 

 which passage is comparatively easy, and of which Ster- 

 rett's gap, the main highway between Perry and Cumber- 

 land counties, is the most conspicuous example. 



The Clinton group, ( V.) 



The southern portion of Rye township consists of an ex- 

 posure of the rocks of this group in beds vertical or slightly 

 overthrown. There is much difficulty in determining the 

 exact thickness of every member owing to the want of clear 

 exposures. But they may be readily traced in their re- 

 spective positions, especially in the lower part of the group. 



The Clinton lower shale occupies the middle of the Blue 

 mountain as explained above. Consequently the top of the 

 mountain is flat and cultivated in some places. So far as 

 it can well be measured here this shale is between 400 and 

 500 feet thick. In this shale lie two beds of iron ore. No 

 good exposure was seen, but both may be traced at Ster- 

 rett's gap. 



The Clinton iron sandstone which supports the middle 

 mass of shale in the Blue mountain, presents the usual ap- 

 pearance of a hard, purplish red sandstone in thin layers. 

 Its thickness is from 10 to 20 feet. As usual its fragments 



