352 THE GREAT ICE AGE 



move somewhat uniformly in a direction from north-east to 

 south-west, and when they touch the bottom, the striation or 

 grooving which they produce must be in that direction. 



In passing through the straits in July, I have seen great 

 numbers of bergs, some low and flat-topped, with perpendicular 

 sides, others convex or roof-shaped, like great tents pitched on 

 the sea ; others rounded in outline or rising into towers and 

 pinnacles. Most of them were of a pure dead white, like loaf 

 sugar, shaded with pale bluish green in the great rents and 

 recent fractures. One of them seemed as if it had grounded 

 and then overturned, presenting a flat and scored surface 

 covered with sand and earthy matter. 



At present we wish to regard the icebergs of Belle-Isle in 

 their character of geological agents. Viewed in this aspect, 

 they are in the first place parts of the cosmical arrangements 

 for equalizing temperature, and for dispersing the great accu- 

 mulations of ice in the Arctic regions, which might otherwise 

 unsettle the climatic and even the static equilibrium of our 

 globe, as they are believed by some imaginative physicists and 

 geologists to have done in the so-called glacial period. If the 

 ice islands in the Atlantic, like lumps of ice in a pitcher of 

 water, chill our climate in spring, they are at the same time 

 agents in preventing a still more serious secular chilling which 

 might result from the growth without limit of the Arctic snow 

 and ice. They are also constantly employed in wearing down 

 the Arctic land, and aided by the great northern current from 

 Davis's Straits, in scattering stones, boulders and sand over 

 the banks along the American coast. Incidentally to this 

 work, they smooth and level the higher parts of the sea bottom, 

 and mark it with furrows and strire indicative of the direction 

 of their own motion. 



When we examine a chart of the American coast, and observe 

 the deep channel and hollow submarine valleys of the Arctic 

 current, and the sandbanks which extend parallel to this 



