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Geology and Mineralogy. 34 
Or 
IJ. Grotocy AND MINERALOGY. 
1. Glacial lakes in the Genesee valley.—The following is an 
abstract of a paper on “The Glacial Genesee Lakes,” read by 
H. L. Farrcnip at the summer meeting of the Geological 
Society, prepared by the author. This paper covered the lacus- 
trine history of the Genesee hydrographic area, and incidentally 
the whole of its Pleistocene geology. The present hydrography 
of the Genesee basin was shown by a handsome map. Upon this 
map the low points in the boundary of the basin, or the passes 
into other drainage systems were indicated, with their altitudes. 
From the head waters of the Genesee in northwestern Pennsy]l- 
vania to Lake Ontario the river has a fall of two thousand feet 
in about one hundred and fifty miles, of which fall six hundred 
feet are covered by the cataracts at Portage and at Rochester. It 
was claimed that during the northward retreat of the ice across 
western New York the ice acted as a moving dam, and the 
ponded waters in the basin escaped by different outlets at succes- 
sively lower levels. The three principal earlier outlets were into 
the Alleghany-Ohio drainage; the important later outlet into the 
Canisteo-Chemung. Counting the primary episode of local lakes 
in the head-water valleys, and the present Ontario phase, the 
author enumerated ten distinct stages in the lacustrine history of 
the Genesee, or nine stages of local glacial waters. The eighth 
stage was that of Lake Warren; the ninth that of Lake Iroquois. 
The numerous evidences of water-levels throughout the basin 
had been studied and measured without at the first attempting to 
correlate them with the several outlets, but a final comparison of 
the height of the terraces with the height of the water-scoured 
cols showed a remarkable and convincing relation. It was proved 
that with the uncovering of each successively lower outlet the 
terraces, deltas and other evidences of water-levels dropped to a 
corresponding height, a relation entirely inconsistent with the 
theory of marine submergence. 
Several local morainic lakes were named of which the draining 
streams had fallen upon rock and been compelled to make rock 
gorges Two of these rock-cuts occur in the main stream, at 
ortageville and at Mt. Morris. 
During the ice-retreat there were several local contemporary 
lakes in the deep side valleys before those valleys were opened 
into the main valley, and these local lakes had their own outlets 
over the divide. There were also tributary lakes, where in a few 
eases north-sloping valleys, outside the divide, poured their glacial 
waters over the divide into the Genesee basin. These and other 
interesting features cannot be properly located and described 
without the map. mt 
It was stated that all the valleys were of preglacial origin, and 
that there had apparently been little reversal of drainage. The 
only conspicuous post-glacial work is seen in the few rock-cut- 
tings, and in the excavation of drift from the old valleys. 
