NIAGARA GROUP. 
91 
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 Niagara 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 bq.nd 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. 
