134 The American Geologist. February, i897 
Erosion. With rapid weathering there is accompanying 
rapid erosion. This is partly due to the fact that the hills of 
liaffln land and Greenland have steep slopes, which have been 
inherited from pre-glacial times, and partly to the fact that 
at certain seasons there is a great supply of water for the 
work of erosion. 
I am told by those who have spent years in the Arctic that 
one can form no conception of the amount of water that is 
engaged in this work of erosion; but even a summer trip pre- 
pares one to partly understand the amount and power of this 
water. During the summer months many of the streams flow 
in their rock-encumbered beds, out of sight beneath the boul- 
ders. One may climb the mountain side in a stream bed, with 
the sound of running water in his ears, and not be able to ob- 
tain a drop from the stream that is coursing along beneath 
the boulders. Then the rain comes, and the streams swell, 
until the water rises above the boulders, overflows the valley 
and becomes a raging torrent. The surface of all the land 
becomes wet, even though the rain fall may have been slight. 
This marked increase in the amount of water in the stream 
is due only in part to the increased melting of the snow banks, 
and only in part to the supply of water obtained from the in- 
creased melting of the frost that is in the soil. It is mainly 
the concentration of the rainfall over the general drainage 
basin. Very little of the water sinks into the earth, partly 
because the greater portion of the land surface is bare rock, 
which readil}'' sheds the rain, and partly because, even where 
the surface is soil-covered, the soil is already nearly saturated 
by water furnished from the frost, which even in the late sum- 
mer exists at the depth of a foot or two below the surface. 
By this the soil is kept constantly damp and usually even 
wet, while below the very surface it is frozen into a solid mass, 
so that there is a barrier to the percolation of water into the 
ground. Naturally, therefore, since most of the water must 
flow away into the streams, even a slight rain causes a per- 
ceptible swelling of all the rivers and rivulets. 
During the winter the surface of all the land, excepting the 
most precipitous, is snow-covered, and with the appearance of 
the summer sun this commences to melt and run away in the 
streams. Snow-born rills and even rivers spring rajjidly into 
