258 IV. D. WILCOX 



So constant is this type of formation, that, upon seeing the 

 ratio between certain mountain valleys, the existence and loca- 

 tion of such lakes may be predicted with almost invariable suc- 

 cess before the lake has been actually seen. The valley of the 

 Little Fork of the Saskatchewan, which is about thirty miles 

 long, has five streams from the west tributary to the main stream, 

 and every valley has a long drift ridge on the upstream side 

 thrown across the openings of the lesser valleys, resulting in the 

 formation of three lakes and two swamps. 



The outline of these drift ridges when looked at from a 

 distance and at right angles to them is quite constant in char- 

 acter. Starting with the rock buttress where the formation 

 commences, the drift is at first very steep and clings to the 

 slopes of the rock. As it continues downward, the slope rapidly 

 decreases in a graceful curve till it approaches an angle of 

 about ten degrees. This slope continues through a great part 

 of its length, only to increase again just before the ridge 

 vanishes as a topographic feature. This curve is represented in 

 almost every one of the many examples observed, and, like the 

 outline of drumlins, may be a mathematical curve depending on the 

 physical nature of ice. In general the outlines of these ridges 

 are smooth like a drumlin or tail formation, and not like a ter- 

 minal or lateral moraine. 



A number of sections were found where streams have cut 

 down through the drift and exposed sections from a few feet 

 up to two or even three hundred feet. In all such cases the 

 formation of the ridges was found to be a regular till without 

 internal arrangement. 



The horizontal projection of these ridges is slightly curved, 

 and remarkably similar to what would be the lines of medial 

 moraines on confluent glaciers from such valleys. Moreover 

 these curves are assumed regardless of the lesser topographic 

 forms and thus give another proof that they are not moraines. 



To summarize the characteristics of these drift ridges, we 

 have the following : 



1. Throughout the valleys of the region under discussion, 



