Rapidity of Wenfheriiu/ in Arctic Latitudes. — Tarr. 135 
existence, and the water cascades down the hills and leaps as 
waterfalls over the face of the cliifs. Some of the snow, the 
banks in sheltered spots, lasts through the suminer; but by 
the middle of July nearly all the winter snow has disappeared 
from southern Biiffin land and from that part of Greenland 
which lies south of Melville bay. For a month or two before 
this there is exceedingly great activity of water action, and 
then it is that cliffs are carved and mountain gorges enlarged. 
I have never anywhere, not even in the high mountains of 
the west, seen such evidence of rapid down-cutting and tor- 
rential flow as that found on every hand in Greenland. The 
stream beds are littered with huge boulders tons in weight, 
and there was one case, in a fjord at the base of the upper 
Nugasuk peninsula, of a delta made of such boulders, which 
had not only been dragged down the valley of the torrent, but 
had been carried out for a hundred yards, over a nearly level 
stretch, and stranded on the edge of a delta whose area was 
several acres. 
Though similar violence of erosive action is often illustra- 
ted in lofty mountains, in this case it was nt)t so much the 
steep gradient of the stream bed which caused the remarkable 
transportation, as the enormous quantity of water turned so 
quickly into the stream. In this region therefore, although 
active erosion is confined to two or three months of the year, 
the sum total of work done exceeds that which rivers are us- 
ually able to accomplish with a full year for operation; and 
the work equals, and perhaps exceeds, that done in mountains 
where, although the slope is greater, the water supply is less 
favorable to intense action. 
Former' Rapid Erosion in Weni York. Even before this evi- 
dence of great intensity of erosion in these high latitudes 
came to my attention, I had thought that our own region of 
eastern United States furnished evidence of intensity of 
stream action greatly in excess of that now being accom- 
plished. Now that I have seen the present results of this in- 
creased intensity, due to great water supply for short periods, 
I feel convinced that this evidence has been correctly' inter- 
preted. 
