THE GEOLOGICAL HISTORY OF NEW YORK STATE 95 
layer, or by accumulation beneath the ice under peculiarly favor- 
able conditions, as perhaps along longitudinal crevasses or fissures. 
One of the finest and most extensive exhibitions of drumlins in the 
world is the region of western New York from Oswego and Syra- 
cuse to west of Rochester. Thousands of drumlins there rise above 
the general level of the Ontario plain, the New York Central Rail- 
road, from Syracuse to Rochester, passing through the very midst 
of them. 
Another type of glacial deposit in the low hill or hillock form 1s 
the kame which, in contrast with the drumlin, always consists of 
stratified drift. Kames are seldom as much as 200 feet high, and 
typically they have rounded bases though frequently they are very 
irregular in shape. At times they exist as isolated masses or hills 
or in small groups, while often they are associated with the unstrati- 
fied deposits of the moraines. When grouped, deep depressions 
occur between the hills to form what is called the knob and kettle 
structure. Kames were formed at or near the margin of the 
retreating ice, and so are found in all parts of the State. They 
most generally occur in valley bottoms, but sometimes on hillsides 
or even hilltops. They are especially common along the line of 
the great terminal moraine (for example, on Long island), and also 
along the line of the important terminal moraine already described 
from central to western New York. For example, in the vicinity 
of Oriskany Falls kames are so numerous as to form a striking 
feature of the landscape in the Oriskany valley. They were formed 
as deposits by debris-laden streams emerging from the margin of 
_the ice, the water sometimes having risen like great fountains 
because of pressure. Such deposits are now actually in process of 
formation along the edge of the great Malaspina glacier of Alaska. 
During the retreat of the ice, glacial lakes were numerous, espe- 
cially aiter the ice front had passed north of the Susquehanna- 
Allegany divide because the north-sloping valleys were dammed by 
the ice thus ponding the waters in the valleys. Some materials 
were directly deposited from the glacier in those lakes, but more 
'was brought in by debris-laden streams flowing from the land 
| already freed from the ice. Such glacial lakes and their deposits 
are common and of unusual interest, but they will be described 
under a subsequent heading. 
In conclusion we may say that the deposition of glacial materials, 
like glacial erosion, has not changed the major topographic features 
of the State. The general tendency of ice deposits has been to fill 
or partially fill depressions and thus to diminish the ruggedness of 
the topography. 
