LIME AND CEMENT INDUSTRIES 765 



Upper H elderb erg 



This is the limestone series which is termed the Corniferous 

 by many writers, but by others the upper member of the series 

 is termed Corniferous and the lower member Onondaga. The 

 formation usually rests on the Schoharie grit, Cauda Galli grit, 

 or Oriskany sandstone, but in the western part of the state these 

 are wanting. The formation is divisible into 3 members, viz: 



1 The lower, or Onondaga graystone, which is coarsely crys- 

 talline and well adapted for building. 



2 The Corniferous, which is a hard and durable limestone con- 

 taining many chert nodules. 



3 The Seneca blue limestone, the purest of the three, fine 

 grained and dark blue. 



The upper Helderberg rocks are quarried near Kingston, Ulster 

 co., at Splitrock, near Syracuse, also at Auburn, Waterloo, Seneca 

 Falls, Leroy, Williamsville and Buffalo. 



The subdivisions of the Onondaga group gradually lose their 

 physical and faunal characteristics in eastern ]N"ew York, and the 

 formation is in greater part a bluish gray subcrystalline, mas- 

 sive limestone with lenticular masses of chert in courses and 

 irregularly disseminated. Darker colors occur locally, notably 

 in the upper beds about Peoria (West Berne), which are very 

 dark and coarsely crystalline. The chert is predominant in the 

 upper beds, but it is usually present also in the lower beds. In 

 places it is an inconspicuous feature but this is not often the 

 case. Thin partings of shale occur rarely. About Saugerties 

 the lower portion of the limestone is shaly and weathers bufiL 

 About Clarksville the lower members are very pure, free from 

 chert and regularly bedded. 



In Greene and Ulster counties particularly the outcropping 

 edge of the formation is characterized by a fringe of very large 

 disconnected blocks occurring at various intervals. In some cases 

 these blocks lie several hundred yards from the edge of the out- 

 crop. 



