72 THE POST-PLIOCENE PERIOD. 



gence, when the old ridges were sometimes bared by denudation, and 

 new ones heaped up.* 



I shall close these remarks, perhaps already too tedious, by a mere 

 reference to the alleged prevalence of lake basins and fiords in high 

 northern latitudes, as connected with glacial action. In reasoning on 

 this, it seems to be overlooked that the prevalence of hard meta- 

 morphic rocks over wide areas in the north is one element in the 

 matter. Again, cold Arctic currents are the cutters of basins, not 

 the warm surface-currents. Further, the fiords on coasts like the 

 deep lateral valleys of mountains are evidences of the action of the 

 waves and currents rather than of that of ice. I am sure that this is 

 the case with the numerous indentations of the coast of Nova Scotia, 

 which are cut into the softer and more shattered bands of rock ; and 

 show, in raised beaches and gravel ridges like those of the present 

 coast, the levels of the sea at the time of their formation. 



In Nova Scotia we have the means of applying another and crucial 

 test to this theory of lake basins. Tbe whole surface of the peninsula 

 has been striated and polished ; and it has been estimated that one- 

 third of its area is occupied by lakes, most of them of small dimension. 

 Now these lakes are almost entirely confined to those metamorphic 

 regions where unequal hardness and imperfect facilities for drainage 

 tend to promote their occurrence. It is evident, therefore, that we 

 are to seek for the origin of the lake basins in these local causes, and 

 not in any universal covering of glacier. Further, as I have above 

 shown, the manner in which the great Canadian lakes have been cut 

 out of the softer materials, and their relations to the neighbouring 

 harder portions of the country, prove that these great basins may be 

 due to the action of ocean-currents, a cause to which I would attribute 

 also the greater part of the smaller lakes of Nova Scotia. To these 

 reasons I may add the following comparative statements of the effects 

 of glaciers and icebergs, deduced from examinations of the glaciers of 

 Mont Blanc and the icebergs of Belleisle : — -J- 



* I have no doubt that Logan, Hind, and Packard, are correct in assigning 

 some of the striation in the Laurentide Hills of Canada and Labrador to glaciers. 

 The valley of the Saguenay, which is a deep cut caused by denudation along a line of 

 fracture traversing the Laurentian rocks, shows near its mouth distinct "roches 

 moutonnees" smoothed on the northern side, and very deep grooves and striae cut 

 in hard gneiss with a direction of S. 10 E. magnetic, which is nearly at right angles 

 to the ordinary striation of the St Lawrence valley. I think it quite possible that 

 these appearances may have been caused by a local glacier, and if so, there may have 

 been glaciers along the whole line of the Laurentide Hills, with their extremities 

 reaching to the sea or strait then filling the St Lawrence valley. 



f Comparisons of the Icebergs of Belleisle and the Glaciers of Mont Blanc, Canadian 

 Naturalist, 1867. 



