34 THE CANADIAN NATURALIST. [Feb. 



under the influence of the current, oscillating slowly with the 

 motion of the sea, and grinding on the rocks and stone-covered 

 bottom at all depths from the centre of the channel, we may form 

 some conception of the effects of these huge polishers of the sea- 

 floor. 



Of the bergs which pass outside of the straits, many ground on 

 the banks off Belle-Isle. V aughan has seen a hundred large bergs 

 aground at one time on the banks, and they ground on various 

 parts of the banks of Newfoundland, and all along the coast of 

 that island. As they are borne by the deep-seated cold current, 

 and are scarcely at all affected by the wind, they move somewhat 

 uniformly in a direction from N. E. to S. W., 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, we saw a great number 

 of bergs, some were low and flat-topped with perpendicular sides, 

 others were concave or roof-shaped like great tents pitched on the 

 sea ; others were rounded in outline or rose 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 accumulations 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 its debris of 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 striae indicative 

 of the direction of their own motion. 



