Geology of Sexeca Coui^ty. 89 



separable in layers, breaking transversely and finally crumbling 

 into small blocks, like the Tally limestone, when exposed to the 

 air. C is two feet of tough, fine-grained limestone, somewhat 

 earthy in its upper part. A and B abound in large coral forms, 

 plainly showing in outline on the surface of blocks, but hard to 

 identify and ill-preserved. They are most abundant in the upper 

 two thirds of B, and hardly occur in C, which, however, presents 

 a few forms of small size. This gives 10|^ feet of blue limestone 

 in three courses. 



Above this is seven feet three inches of a highly argillaceous 

 limestone (D), not found to contain fossils; readily separating 

 into flat pieces an inch and upwards in thickness, especially in 

 the upper parts. When fresh much of it is clear dark blue, some- 

 times ringing when struck. Weathering gives a buff tint, softens 

 the surface at joints to an earthy consistency, showing the 

 laminae in earth, and has reduced the top layers (one to five 

 inches) to a sort of yellow ochre. The owner says that C and D 

 are good for making cement. 



The junction of D and E was carefully searched, but not a 

 fragment of material resembling the Oriskany sandstone was 

 found. Its absence from this county was noted by Prof. Hall 

 (Kept. 4th Dist., p. 456). The upper layers of D are in ihin 

 slabs, weathered to ochreous dirt to different depths, and in places 

 displaying their form up to the level of contact with E. The 

 under side of E is also badly weathered, crumbled into small 

 pieces of an ounce or two. It seems important to have some- 

 thing positive or negative as to the relation of these blue 

 limestones to the Lower Helderberg. They have in part the 

 lithological aspect of that rock as foand by S. G. Williams, at 

 Union Springs, but the total difference of fauna is noteworthy. 



The Onondaga limestone (E) is unquestionably in situ, and 

 quantities lie about among the other rock, evidently recently 

 removed. 



The strata dip moderately S. W. 



The Oriskany sandstone, an abundant and prominent compo- 

 nent of the drift south of Auburn, derived from well-known 

 exposures, is certainly not at all common in the drift of Seneca 

 county, though easily recognized on account of its peculiar 

 aspect. 



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