ORISKANY SANDSTONE. 



123 



16. ORISKANY SANDSTONE. 



White Sandstone of the Report of 1838. 



(No. 7 OF THE Pennsylvania Survey.) 



28. 



^^"1^ 



No. 1. Arenaceooi delthyria (D. arenaria). No. 2. Elongated atrypa (A, elongata). 



No. 3. Peculiar atrypa (A. peculiaria). 



This sandstone holds a fixed position in the series, and is readily traced from east to west 

 through the district, by its composition and its numerous characteristic fossils, not so much as 

 to kinds as individual species. Its position is best seen in the first district near Salem ; the 

 Helderberg division, of which it forms a part, being complete. It projects from the side of 

 the Helderberg mountain, forming a terrace resting upon the Catskill shaly limestone, in the 

 upper part of which the encrinal pelvis is found ; the sandstone passing under, or covered 

 with the cauda-galli grit, the latter being a thick abrupt mass. 



In the third district, its immediate associates cease entirely before reaching the west end of 

 Madison coimty ; and the sandstone from thence rests upon the Manlius water-lime group, 

 and is covered by the Onondaga limestone, the three rocks being coassociates to Cayuga lake. 

 It is very variable in thickness, owing probably to the unevenness of the surface upon which 

 it was deposited. 



With some exceptions, this sandstone consists of a medium sized quartz sand, such as is 

 derived from primary rocks, either of granite, gneiss or mica schist. It is of a light yellow 

 color when pure, as at Oriskany falls. At other localities the yellow color is often shaded 

 brown, or of some other dark color. This sandstone and the calciferous sandrock, including 



