6o 



ERNEST DeKOVEN LEFFINGWELL 



formed one side of a channel melted to a depth of five feet by the 

 surface waters. We have seen that the ground ice probably under- 

 lies the whole island, that it is covered with glacial drift, and contains 

 boulders imbedded within it; so the conclusion is forced upon us 

 that our island is simply a portion of a glacier that has been kept 

 from melting by a thin coating of drift upon its surface. 



Naturally the mountains on the mainland to the south are to be 

 looked to for the source of the glacier by which Flaxman Island was 

 formed. As we have said, a chain of mountains about three thousand 



Fig. 3. — A characteristic exposure, 



feet high runs parallel to the coast at a distance of some thirty miles 

 inland. Through this the Kugura River breaks after heading among 

 the higher peaks beyond. As seen from a distance, the nearer range 

 does not seem to have suffered intense glaciation. It certainly was 

 not covered by an ice cap ; but small glaciers may have occupied the 

 valleys on the north side. The presence of a piedmont glacier is 

 not improbable. The deep cut of the Kugura, however, in its rounded 

 outhne has a heavily glaciated look, and it is here that we must look 

 for the source of the ice that forms our island. 



In his report on the Koyukuk, John, Anaktuvuk, and Coville 



