58 F 3 . REPORT OF PROGRESS. E. W. CLAYPOLE. 



Bistline's mill, where the sandstone, about 5 i'eet thick, lies 

 on 500 feet of Red shale, and under about 200 feet more, 

 giving as a total amount 700 feet, the same as elsewhere. 



In this connection may be pointed out the approximate 

 contemporaniety of the formation of these beds of sand- 

 stone, however deposited, with the shallow water or dry 

 area in Rye township at the close of the Onondaga area. 

 See report on Rye township. 



No. VI. Lower Hetderberg group. 



The rocks of the Lower Helderberg group possess in this 

 county a well defined summit, but an ill defined base. Up- 

 wardly they stop at the base of the Oriskany sandstone, 

 but downwardly they graduate into the shales and marls 

 of the just described Onondaga group. It is consequently 

 impossible to draw a clear plane of division between these 

 groups, and certain passage beds must remain debatable 

 ground. In this case also the classification adopted is 

 merely provisional pending the collection and study of fos- 

 sils from these beds in other parts of the State, many of 

 the beds being almost barren in this county. 



The Lewistown (Bossardville) limestone. 



The Lower Helderberg rocks, largely of limestone, are the 

 only beds much quarried for lime. Commencing below we 

 find, first, a mass of hard, dark, often bituminous and 

 sparry limestone, in beds several of which are from two to 

 four feet thick. Above and below these they become thinner 

 with increasingly numerous partings of shale. This massive 

 limestone is the lowest to which the name of the Lower 

 Helderberg is here applied. Minute examination of a 

 weathered surface shows that it is composed of alternate 

 very thin layers, which show darker and lighter tints but 

 no tendency to separate. All these beds are burned at dif- 

 ferent places and yield ordinary quicklime. I have seen no 

 indication of hydraulic properties in any of them. The 

 burnt stone slakes readily in the air. The thickness of this 

 part of tin' group, so far as can be judged from numerous 

 l)ii t imperfect exposures, does not exceed 100 feet. 



