GLACIAL EROSION OF LAKE BASINS 



gigantic scale, we iind a grand series of valley-lakes both 

 on the north and south of the Alps, situated for the most 

 part in the tracks of those enormous glaciers whose former 

 existence and great development is clearly proved by the 

 vast moraines of Northern Italy and the travelled blocks 

 of Switzerland and France. In Scandinavia, where the 

 ice-age reigned longest and with greatest power, lakes 

 abound in almost all the valleys of the eastern slope, while 

 on the west the fiords or submerged lakes are equally 

 characteristic. 



In North America, to the south of the St. Lawrence 

 River and of Lakes Ontario and Erie, there are numbers 

 of true valley-lakes, as there are also in Canada, besides 

 innumerable others scattered over the open country, 

 especially in the north, where the ice-sheet must have been 

 thickest and have lingered longest. And in the southern 

 hemisphere we have, in New Zealand, a reproduction of 

 these phenomena — a grand mountain-range with existing 

 glaciers, indications that these glaciers were recently much 

 more extensive, a series of fine valley-lakes forming a true 

 lake district, rivalling that of Switzerland in extent and 

 beauty, with fiords on the south-west coast comparable with 

 those of Norway. 



Besides these valley-lakes there are two other kinds of 

 lakes always found in strongly glaciated regions. These 

 are alpine tarns — small lakes occurring at high elevations 

 and very often at the heads of valleys under lofty preci- 

 pices ; and small or large plateau or low-level lakes which 

 occur literally by thousands in Northern Canada, in Sweden, 

 Finland, Lapland, and North-western Russia. The valley- 

 lakes and the alpine tarns are admitted by all geologists to 

 be mostly true rock-basins, though some are partially and 

 others wholly dammed up by moraines or by land-slips ; 

 while the plateau and* low-country lakes are often mere 

 hollows in the drift with which much of the country is 

 covered, though rock-basins are also not unfrequent. 



Here, then, we see a remarkable association of lakes of 

 various kinds with highly glaciated regions. The question 

 is whether there is any relation of cause and effect in the 

 association ; and to determine this we must take a rapid 



VOL. I. H 



