The Margin of the Cornell GUicier. 155 
On the steep hill sides it has been washed off from the rock, 
so long smoothed bj^ the ice and made slippery bj' the melting 
of snow and frost in the summer. In the torrents of early 
summer most of it has left its place, and the hill sides have 
been left nearly bare.* The proof of this is found in the pe- 
culiar distribution of the boulders. It was noticed that on 
the hill sides, and even on many of the hill tops, the only re- 
mains of glacial deposits were boulders, most of which either 
rested on pebbles, or on a flat face, either of their own or of 
the bed rock. The characteristic condition of the boulder 
was perched on two or three pebbles, and so raised above the 
bed rock that one could look beneath the boulder to points be- 
yond. Thus perched in a stable position, some of the bould- 
ers have remained, while the small beds of clay and pebbles, 
and the less favorably placed boulders, have gone away, leav- 
ing these as monuments testifjMng to the former presence of 
at least some drift. 
Comparison of Greenland and American Glacial Dejtosif.s. 
.While it is true that from the Greenland glacier were obtain- 
ed many hints concerning the conditions existing during the 
American glaciation, it is equally true that the conditions in 
the two places were widely different. In the first place the 
topography of Greenland is unlike that in most of the United 
States, finding its nearest analogue in the Adirondack? and 
northern New England region. Then too, the greatest activit}* 
of the Greenland glacier is in the vallej'^ glacier tongues, 
which end in the sea, wliile for America the glacier end was 
mainly on the land. Where the glacier ends against the land, 
the cause for this terminus is onl^^ partly that of melting. 
Much of the material brought toward the land margin even- 
tually goes into the neighboring sea, either in streams or in 
the ice directly, as this is deflected by the land. 
Morever the amount of debris carried by the American gla- 
cier was very much in excess of that now being transported 
by the Greenland ice sheet. This may be due to the greater 
hardness of the Greenland rock, though this is not greater 
than in parts of New England. The conditions on Labrador 
and Baffin land are more nearly like those on the margin of 
Greenland than the United States. I believe this is because 
*Tarr, Am. Geol., vol. xix, 1897, p. 131. 
