of the North American Ice-Sheet. 207 
Massachusetts was by Mr. Clarence King,* who examined 
Naushon Island and pronounced it, with the similar formation 
continuing on Cape Cod, to be a series of deposits accumulated 
at the margin of the continental ice-sheet. The same conclu- 
sion has been announced by the geologists of Wisconsin and 
Jersey respecting the series which cross those States. At 
nearly stationary through a long period, in which the materials 
that it contained were being continually brought forward and 
deposited.t In many places these would be pushed into very 
irregular heaps and ridges by slight retreats and advances of 
the ice-margin. At the same time we should also expect that 
thick beds of ground-moraine would be gathered beneath the 
ice Near its termination, The withdrawal of the glacial sheet 
u many parts of these series, however, the materials brought 
by the ice have been covered by modified drift brought by 
glacial rivers; so that the three divisions of the drift join to 
form the terminal moraines. No similar series of drift deposits 
seems to have been discovered north of the second here 
described, and we may conclude that in general the retreat of 
the ice-sheet did not admit sufficient pauses for their formation. 
* Proceedings of the Boston Society of Natural History, vol. xix, p. 62 
ase In Long Island an 
ern end, adjoining the city of New York, we find serpentine, red sandstone, an 
Various erevtiio snd setae rocks, which have come frem the district lying 
Mamediately to the north.” were 
Excepting the pre-gilacial deposits which _ been mentioned, and a small area 
oe ms c consist of drift deposits which owe their accumu- 
lation, as has been aie eh to the action of the ice-sheet and its rivers in 
amassing them at its termination. 
