TO4 NEW YORK STATE MUSEUM 
Many of the existing Adirondack lakes were formerly of larger 
extent as proved by delta deposits above the present lake levels. 
Two lakes of this class recently coming under the writer’s observa- 
tion are Schroon lake in Warren-Essex counties, and Piseco lake 
in Hamilton county. The water of Schroon lake was once fully 
70 feet higher when it extended some eight or ten miles farther 
up the Schroon river, with a branch reaching over the area of the 
present Paradox lake, and also for some six or eight miles farther 
southward to cover all the lowland around Chestertown, and with 
a prominent branch extending over the area of the present Brant 
lake. Piseco lake was at one time clearly twenty feet higher, and 
then extended several miles farther northward. 
The valley of Lake Champlain was favorably situated for ice 
erosion, and it bears evidence of having been vigorously glaciated 
though it has not been proved that the existing closed basin is 
chiefly due to ice erosion. At the close of the Ice age, tide water 
entered the valley. The present lake basin is due principally to a 
combination of late elevation of the land, with greater uplift on 
the north; heavy glacial accumulations toward the north; and 
possibly some deepening as a result of ice erosion. . 
Lake George is justly famous because, from the standpoint of 
length and depth in proportion to width, no other lake in the State 
occupies such a remarkable depression. This depression has been 
determined by ordinary erosion along lines of prominent faults. 
There was a preglacial divide where the “ Narrows” are now 
located, and this divide appears to have been considerably lowered 
by ice erosion when part of the Champlain ice lobe plowed its way 
through the deep, narrow valley. The waters are now held in by 
glacial deposits at each end. és 
In southeastern New York, from the Connecticut state line west- 
ward to the southern Catskills in Sullivan county, there are many 
lakes, though all are comparatively small. With few exceptions 
these lakes appear to be of the usual drift dam type. Greenwood 
lake, at an altitude of 621 feet and passing from Orange county 
across the state line into New Jersey, is the largest in this part of 
the State. Three small lakes near the summit of Shawangunk 
mountain, and close to its eastern edge, deserving special mention 
are: Mohonk, Minnewaska, and Awosting. Mohonk lake, which 
1s so widely known both because of its remarkable situation and 
as a place where so many peace conferences have been held, may be 
taken as the type of the three. The altitude of this lake is more 
than 1200 feet or about 1000 feet above the base of the mountain 
