ROLLIN D. SALISBURY 



where the main ice-sheet approaches the local ice-cap of the 

 peninsula between Bowdoin Bay and Inglefield Gulf, the edge 

 of the former shows similar phenomena on a much more exten- 

 sive scale. Here drift comes up to the surface, not between all 

 adjacent layers of ice, but only between certain layers. The 



I 



Fig. 26. — Belts of debris on the edge of the ice-cap west of Hubbard glacier. 

 Each belt is confined strictly to the line of outcrop of an upturned debris-bearing 

 layer. 



larger part of it is in five distinct zones, which mark the out- 

 crops of as many debris-charged horizons of ice. Each one of 

 these belts of drift is irregular, here higher, there lower, so 

 that each belt, instead of being a continuous and even-crested 

 ridge of drift, is really a succession of mounds. Where the 

 mounds attain considerable proportions, the drift spreads from 

 their bases, so that high mounds are also always wide. Where 

 two adjacent belts of drift are both irregular, it frequently hap- 

 pens that the mounds along one belt spread to such an extent 

 that their bases are confluent with the bases of the mounds of 

 the other belt. 



These phenomena, repeated for all five belts of drift, gave 

 rise to a peculiar and suggestive disposition of debris on the 

 surface of the ice. Where the five belts approach each other 

 so closely that the spreading drift of one becomes confluent with 

 that of those adjacent, the surface of the ice for considerable areas 



