196 The American GeologisL March, 1897 
to deepen the depressions formed by this action, though ice 
erosion would not in this case be the prime cause for the 
basin. 
Recency of ice withdrawal. Notwithstanding the absence 
of distinct rock striie, it is evident, for several reasons, that 
the ice has not long been away from Baffin land. The marked 
weathering of the surface rock suggests considerable length of 
time; but in using this as a basis for an estimate, it must be 
remembered that the severe weather changes of the Arctic, ev- 
idently produce marked results in weathering in a very 
short time.* In the till beds, which were found in greater 
thickness and abundance in Cumberland sound than in the 
other places that have been described, there is much less evi- 
dence of modification. The strije on the pebbles are still dis- 
tinct, and the till not markedly decayed, nor even the weaker 
pebbles disintegrated. Weathering on the exposed and fri- 
able gneissic bed rock has been far more rapid than in the 
unconsolidated deposits in which frost action is able to pro- 
duce less effect. 
Evidence of recency of the ice withdrawal is also furnished 
by the lakes of Baffin land. Some of them have two outlets 
and others have more. Tliis certainly could not have been 
possible had the water been overflowing the rims of the basin 
for any considerable length of time. It would not be long 
before one of the outlets, in its action of down-cutting, would 
so exceed the rate of work of the others that all but one would 
be abandoned. Pointing toward the same conclusion of re- 
cency is the fact that even where torrents enter shallow lakes 
from the higher hills, the materials that have been brought by 
the streams have not yet been able to build perceptible del- 
tas in most of the lakes. 
ConclKbions. The conclusions to be reached from this very 
brief reconnaissance study of parts of Labrador and Baffin 
land are, in the first place, that all of the land, excepting pos- 
sibly the highest parts of Baffin land and Labrador, has been 
buried beneath an ice sheet. The possible exceptions, in all 
probability, are not real cases of unglaciated land, but rather 
high land that rose into the ice, and in the early and later 
stages of glaciation extended above it, as is the case inGreen- 
*See Tarr, Am. Geol., xix, 1897, 131. 
