160 The American Naturalist. [February, 
of which are among the characteristic members of the molluscan fauna 
now living in the waters of the Mississippi drainage system. (Proceeds. 
U. S. Natl. Mus., Vol. X VII, 1894.) 
Glacial Lakes in Western New York.—This subject is 
treated in two papers which describe briefly the glacial lacustrine his- 
tory of Western New York, introductory to fuller treatment hereafter. 
The author shows, with the aid of specially prepared maps, how the 
remarkable valleys of the “ finger lakes” terminate abruptly at 
their southern ends in the high land which forms the divide between 
the St. Lawrence and the Susquehanna—Ohio waters. The deep pre- 
glacial valleys, cut to some unknown depth through the divide, have 
been partly filled with frontal moraine drift-making cols, which were 
the waste-weirs for the glacial waters. 
As the ice-sheet slowly retreated northward, it was a barrier to the 
waters which were poured in the south ends of these deep valleys and 
forced to overflow into the Susquehanna. In all the valleys a well- 
marked abandoned stream channel is found south of the col, while 
north of the col are found the delta deposits of the streams which 
emptied into the glacial lakes at their maximum and later levels. 
The author described with some detail several of those local glacial 
lakes, among which were the Watkins (glacial Seneca) Lake, which 
at its maximum was about thirty miles long, some four to eight miles 
wide and one thousand feet deep. The Ithaca (glacial Cayuga) was 
even larger and deeper than the Watkins Lake. The deltas and shore 
inscriptions of all the glacial lakes are well marked, and in this lies 
proof of the power of ice to act as barrier to deep water. 
Glacial lakes also occupied valleys in which to-day there are no lakes, 
but free northward-flowing streams, as the Tonawanda, Canaseraga, 
Genesee, Onondaga and others. Professor Fairchild named eighteen 
of the local glacial lakes from Attica on the west to Tully Valley on 
the east. 
-~ As the ice-lobe damming each of the several glacial lakes melted, 
the waters were lowered into the level of the great water body which 
buried all of Western New York north of the divide and most of the 
area of theGreat Lakes. At first this water had its outlet at Chicago, 
and has been named by Mr. Spencer, Lake Warren. But when the 
ice by its retreat finally uncovered the Seneca Valley, the outlet of the 
Watkins Lake at Horseheads became, owing to the depression of 
the “ Finger” lakes region, the outlet of the Continental lake, and this 
remained the outlet until the ice, by its further retreat, uncovered the 
