CAYUGA COUNTY. 
285 
Hamilton group. This group covers a great area, nearly one half of the county; extends 
south from the Marcellus shales, to the county line of Cortland, with the exception of some 
parts in the towns of Fabius, Tully and SpafFord, which are covered with higher rocks, forming 
a part of those which project north from Cortland county, and which form the greater part of 
the surface of that county. The whole of the area of the Hamilton group presents a succession 
of deep north and south valleys, two of which are occupied by Otisco and Skaneateles lakes. 
The direction of these lakes, however, like those further west, inclines towards the southeast. 
The whole of the valleys which extend over the area are connected with southern ones, the 
waters dividing below the tops of the hills. Numerous small lateral valleys branch from the 
larger ones, affording facilities for the examination of the parts of which this thick group is 
composed. Besides these small valleys, there are a few of greater extent, the largest of which 
is to the south of South-Onondaga village, extending to the quarry near Marcellus village. 
There is very little shale in this group of so dark a color, fine a grain, and so much dis¬ 
posed to be slaty as in the Marcellus shales ; being more coarse, very fine sand of a brownish 
yellow color entering into its composition, which becomes evident from long exposure. In 
many localities, it appears as an exceedingly fine-grained sandstone of a yellowish grey color. 
Portions of the shales and sandstone varieties are calcareous. The great mass at Pratt’s falls, 
Gamble’s falls, the north shores of Skaneateles lake, and numerous other noted points, show 
the finer kind of shale; the coarser at Buhr’s falls on a branch of Limestone creek, at Pom- 
pey hill in numerous places, at South-Onondaga, in the ravines of Otisco lake, etc.; and the 
more solid or hard kind forms the upper rock at Pratt’s falls, the quarries on Pompey hill, etc. 
Fossils are exceedingly numerous throughout the whole mass ; no locality without them. 
Tully Limestone. This last of all the New-York limestones in the ascending order, appears 
in several places over the area occupied by the preceding group. Its localities are, near the 
village of Delphi; at the northeast of the town of Otisco ; at Smith’s, on the hill-side of the 
inlet in the valley of Otisco lake ; on the opposite side of the same valley ; on the road from 
Otisco village to Tully four corners ; at the latter place also, whence its name ; at Tinker’s 
falls, on the edge of Cortland in Fabius ; and near Borodino. 
The Genesee slate, and the base of the Ithaca group, are the last and highest geological 
masses of the county, occupying the extreme southeast of Fabius, the larger portion of Spaf- 
ford, and a portion of Tully. 
The southern end of the county is somewhat peculiar, showing a system of broad, east and 
west valleys, interlocking with those whose course is north and south. The hills decline 
south, being quite low through the towns of Tully and Fabius, evidently the result of wear or 
washing away in the direction of the great north and south drains of that section. 
9. Cayuga County. 
This county, from its extending further north than Onondaga county, contains two rocks 
more, the redstone of Oswego, and the extension of the Oneida conglomerate, which in this 
