BOULDERS. 211 



British Museum, and the naturalists who have compared 

 it with recent skulls of the animal brought from Melville 

 Island or Churchill, perceive no difference. But, as the 

 species is not known to frequent any district to the west- 

 ward of the Mackenzie, the transport of any of its bones in 

 modern times to Kotzebue Sound cannot be readily ac- 

 counted for. 



In a preceding page I have alluded, in a general way, 

 to the distribution of boulders on the eastern prairie slope 

 and in the valley of the Mississippi. The journal of the 

 voyage shows that these are everywhere present in the 

 north. The surface soil, the beds of rivers, and sea-shore 

 abound in them. I noticed them also in various places 

 accumulated in clusters, forming small eminences of from 

 10 to 100 yards in diameter, and from 8 to 20 feet high. 

 These may be ice-borne boulders. The usually circular 

 form of the heaps militates against their being glacier 

 moraines. Such collections are of frequent occurrence on 

 the borders of Great Bear Lake, and in the valleys that 

 separate the spurs of the Rocky Mountains, — several 

 hundred feet above the present levels of the lakes and 

 rivers. They also occur in more southern localities. 



p 2 



