94 
GEOLOGY OF THE THIRD DISTRICT. 
At Whiting quarry in the town of Cicero, there are some geodes lined with rhombic crys¬ 
tals of carbonate of lime : Gypsum, in small globuliform accretions, has also been found in 
some of the other quarries, showing that the same causes have operated in this group as well 
in the third as in the fourth district; the geodes especially being so numerous in the latter one. 
The calciferous slate of Prof. Eaton, which underlies the limestone of Niagara, Lockport, 
Rochester, &c., which is quite a thick mass at Wolcott village, is seen but for a short dis¬ 
tance in the third district. At Hyde’s quarry near Plainville, it appears there is a dark 
colored shaly limestone containing Strophomena depressa, Orthis hybrida which somewhat 
resembles the O. testudinaria, fragments of the Asaphus caudatus, the Orthis bicostata, and 
some slender stems of an encrinite which is also found in the group further east. 
12. ONONDAGA SALT GROUP. 
Calciferous Slate , or Second Greywacke, with Shell Limeroch of Eaton. 
This is one of the most important groups of the district, containing all the gypsum masses 
of western New-York, and furnishing all the salt water of the salines of the counties of Onon¬ 
daga and Cayuga. The group is coextensive with the district, commencing in the first dis¬ 
trict, and extending through the third and fourth districts into Canada. It rests upon the 
Niagara group, from the middle part of Herkimer county, throughout its whole course west. 
From the point where the Niagara group terminates at the east, it rests upon the Clinton 
group; and as the latter group also comes to its end near the first district, it reposes there 
upon the Frankfort slate, upon which it continues to near the Hudson river. 
It forms a part of the high range on the south side of the Mohawk ; appearing at the north 
end of Otsego county, and in Herkimer and Oneida, being its northern outcrop. It makes 
its first appearance by the side of the Erie canal at the east end of Madison county, and 
from thence west the canal was excavated in the group ; the extent of surface on the north 
side, after a few miles, becomes as great as that on the south side ; the group increasing in 
breadth on both sides of the canal, in extending itself through the district. The great descent 
from the high range is due to the dip of the rocks to the southwest, and the rise of the bot¬ 
tom of the valley. The extent of surface which the group covers, or which is exposed to the 
west of Oneida, was owing to its forming a part of the great level, whose rocks escaped that 
destruction which befel the same rocks to the east; and those masses which covered the rocks 
of the great level, shared the fate of the rocks of the level, at the east. That such was the 
fact, appears evident from the range of the Helderberg division, which extends along an east 
and west line; the Onondaga salt group projecting beyond that line to the north for some 
miles, through the three terminal counties of the district. The high east and west ranges of 
