No. 275.1 
331 
a height of no iiiore than twenty feet; the summits of others are fifly, 
sixty, or even a hundred feet above the general surface. They are com- 
posed of sand, which usually forms the covering of the whole, and gravel 
and pebbles from the rocks north j as the green sandstone of Salmon ri- 
ver, and the red sandstone bordering Lake Ontario. 
The abrupt northern and the gradual southern slope of the ridges, 
together with the materials of northern origin, prove the course of the 
current. Their bearing here Is uniform, and in the direction of Cayuga 
and Seneca lakes, through whose valleys the accumulated waters found 
a passage southward. The irregularity of these hills farther west, 
doubtless resulted from obstructions offered to the course of the current, 
by the more elevated part of the limestone terrace. 
The first or lowest alluvion which has been recognized, is a dark 
coloured gravel,* generally containing in the middle range of counties, 
abundance of pebbles of dark limestone, a character however which 
varies with the distance from the rock; the greatest proportion of peb- 
bles of any rock being within a liniited distance south of the mass in 
place. The last deposit is variable in composition, but of finer mate- 
rials than the first, and is always known by a reddish tinge derived from 
the destruction of the red shale of the Onondaga saliferous group. This 
colour distinguishes the soil for twenty or thirty miles south of the ori- 
ginal rock, decreasing in intensity with the distance. The general cha- 
racter of this red soil is a clayey gravel, but varies from intermixture 
with materials from beneath and disintegrated rocks; and at some 
points, the removal of this soil since its deposition has exposed the 
dark gravel below. 
The lower alluvion is less strongly marked in the southern couaties; 
here it occurs mostly in ancient water courses. The great valleys par- 
take largely of its character, and pebbles from the limestone and other 
northern rocks are found abundantly in the valley of the Chemung river, 
and on the southern border of the State. The valley south from Seneca 
lake is a well characterized example, the gravel being composed prin- 
cipally of northern rocks, and much worn and reduced in its progress 
southward. The upper alluvion of the southern counties is beyond the 
influence of the red shale, and does not present its distinguishing 
colour. 
* In the Third District Mr. Vanuxera finds below this a deposit of sond; which doubtless will 
also be found in the Fourth District. 
