No. 2l3. \ 
249 
to the same cause which gave rise to this appearance common to the 
iron ore of the group. 
Of the fossils of this rock, there are two which have been found only 
in this rock. The Orthis bicostata is abundant, occuring in Oneida, 
Onondaga and Cayuga. The other is the Pterinea gibbosa, which is 
not common or abundant. 
Red Shale and the Water Limes of Herkimer and Oneida^ 
which we shall call in this report, the saliferous group of Onondaga* 
This group comprises four deposits, between which there are no well 
defined lines of division, but for practical purposes, the divisions are 
obvious enough. 
The first or lowest is the red shale; 2d. The lower gypseous shales, 
the lower part intermixed with the red shale, the red shale ceasing 
entirely with this mass; 3d. The gypseous deposit, which embraces 
the great masses quarried for plaster, the hopper shaped cavities, the 
" vermicular limerock " of Eaton, and other porous rocks; and 4th, and 
lastly. Those rocks which abound in groups of needle form cavities, 
placed side by side, caused by the crystallization of sulphate of magne- 
sia, which may, from that circumstance, be called the magnesian de- 
posit. 
These masses occur from the eastern part of Madison to the extreme 
western limit of the Third District. 
The whole of the group, leaving out its gypseous and magnesian con- 
stituents, may be stated generally, to be of argillaceous materials, mean- 
ing thereby, silex and alumine in the state of indurated clay, and of car- 
bonate of lime. The former abounding in the lower or red shale mass, di- 
minishing upwards, whilst the carbonate of lime which is but percepti- 
ble in the lower part, increases and is in great excess towards the upper 
part. 
From the limestone of the protean group, w^e pass, going south by 
a few thin beds of alternating green and red shale, and a thin bed of 
hard green sandstone, to the great mass of the red shale. At least such 
are the results of observation throughout the counties of Herkimer and 
Oneida, where these masses are presented in the wall of the great ele- 
vation, and we have no reason to believe that any change has taken 
place, other than a thickening or thinning of some of the lower beds, not 
f Asscm. No. 275.] 32 
