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V. H. BARNETT 



at the time of the writer's visit, an excellent opportunity was presented 

 to observe them. The pavements are composed of variously sized 

 rock fragments, from a few inches in diameter up to two or three 

 feet, sometimes water-worn, but more often angular, with their upper 

 side smooth and striated parallel to the stream. 



There seems no doubt, therefore, that moving ice if equipped with 

 proper means could produce the furrows observed in the gravels. 



Fig. 2 



Cut banks occur on one side or the other of the rivers throughout 

 the fiats, from which spruce trees are certainly tumbling during 

 summer. An uprooted tree held to the river bank by some of its 

 roots would serve as a lodgment for drifting trees and the whole 

 mass would be frozen in the ice as it formed. In the spring, with the 

 heavy pressure of an ice jam, the mass would be dragged along intact, 

 producing such forms as shown in Fig. 2, but ice blocks caught in 

 the jam probably occupy an equally important place in the origin of 

 these lines. 



