Review and Comment. 
349 
indicating the site of an old N. N. E. and S. S. W. valley of 
erosion, nearly in the direct course of the stream. The glacial 
deposits evidently filled this ancient valley, and thus forced the 
stream from its course, giving it a bend around south and west 
where by a fall of about eighty feet it regains its old channel. 
A. Holland 22 states that the fjords of Norway are deeper in 
their middle portions than at their mouths where they are trav¬ 
ersed by old moraines. The same is true of those of Scotland; 
and if the land should rise the fjords of these countries as well 
as those of Greenland would become lakes similar to Lake Mag- 
giore and other lakes of the southern Alps. 
In common with Nansen and some of the other Scandinavian 
geologists, Helland believes in the glacial origin of the fjords. 
Professor W. M. Davis, 23 in his paper on the classification of 
lake basins, gives glacial erosion a minor place among lake 
forming agencies. He says it is certainly possible for glaciers 
to cut out rock basins but thinks the number and size of such 
basins have been greatly exaggerated. 
He gives a discriminating review of the works of the various 
earlier writers on this subject and says in a brief summary that the 
difficulties that lie in the way of accepting a glacial origin for the 
large lakes are, in addition to the inefficiency of glacial erosion, 
first, that the necessity for the acceptance is not proved, as 
many of these lakes have other and sufficient causes; second that 
the distribution or location of rock basins is not sufficiently con¬ 
trolled by glacial but rather by orographic conditions. 
He thinks Norway and Sweden undoubtedly possess many 
true rock basins of glacial erosion, but questions whether drift 
barriers may not explain the greater number of lakes there as 
they do in Finland. 
He emphasizes the lack of exact data for lakes supposed to lie 
in rock basins and the overlooking of drift barriers, etc., as com¬ 
petent causes. 
The formation of a lake is sometimes a simple, sometimes a 
■complex affair. 
22 GEfoers K. Svenska Vet. Akad. Forhandl., No. 4, pp. 13-33. 
23 Proc. Best. Soc. Nat. Hist., Jan. 18, 1882. 
