NIAGARA GROUP. M 



4 



Cayuga, as the limestone increases in thickness, and is of a better quality going west, it is 

 quarried both for building and burning for lime. 



The position of the Niagara group is well defined, being south of the Clinton group, upon 

 which it rests, and north of the Onondaga salt group, the latter resting upon the Niagara group, 

 as in the wood-cut below, which shows the shales, etc. : No, 2, 3, 4 and 5 of the Onondaga 

 salt group, and No. 1 of the Nicigara group, as seen at Hart's mill on the east branch of Oris- 

 kany creek. 



13. 



In Swift creek in Oneida, large dark-colored flat concretions of impure limestone appear, 

 with some cavities containing crystals of carbonate of lime. These concretions are enclosed 

 in a slate or shale of the same dark color. Between this mass and the red shale there are 

 about twenty feet of blue and greenish shale and slate, all which disappear before reaching 

 Crugar's mill to the east, where the red shale and the grey band must be in contact. 



At Hart's mill, on that branch of the Oriskany which comes from Waterville, is a favora- 

 ble place for examining the concretions of the group ; they are there enveloped in the same 

 slate, and present the appearance exhibited in No. 1 of the preceding wood-cut : they are 

 well defined, large, and more connected together than in some of the other localities. In the 

 concretions near Hamilton college. Dr. Noyes found a little galena, blende and crystallized 

 carbonate of lime. 



At Vernon, going west, is the first place where fossil shells were seen in the mass ; they 

 are quite numerous in the slate which contains the concretions, and consist of the Orthis 

 bicostata of Conrad, the specimens of which were obtained too late for a wood-cut. The 

 concretions are well defined, rising from the bottom of the creek by the side of the village, 

 like mounds in miniature, not being over two or three feet in diameter. 



The same concretions appear on the road towards Skanandea, and also in the creek at that 

 village, extending for some distance both ways, the rock forming the bottom of the creek. 

 By the side of the creek at Squire Breese's there is a chalybeated salt sulphur spring, which 

 rises through the rock. It was conjectured to be a highly eligible point to bore for coal, 

 which was the intention of its enterprising owner ; but since the survey has proved that the 

 rocks of the New-York System hold an inferior position to those of the coal, the project has 

 been abandoned, and a boring for stronger water will be made. Higher up Skanandea creek, 

 back of Turkey-street, is a favorable point for the examination of the group as it appears to 

 the east, the banks of the creek being higher, and more of the group exposed. It is more 

 variable, the slaty shale predominating near the bridge, and the calcareous layers lower down. 



