ICE SHEETS AND GLACIERS 



that it had not altered much since 1902. Considerable 

 accretions were, however, due to snowdrifts. This was 

 evident in the fresh cross sections of the stranded 

 tongue which we saw later near Cape Bernacchi. The 

 snow sections showed great folds in the layers but 

 were possibly only marginal accretions built up from 

 ancient cornices. 



I am of the opinion, however, that the tongue is 

 partly a relic of piedmont-ice buttressed by a submarine 

 ridge or moraine near the coast. For the most part it 

 is floating, as there is no tide crack between it and the 

 sea-ice. In the past it was moving outwards and we 

 see signs of this in the large undulations, but there 

 seems no ''driving-power" to cause these nowadays, 

 for there is little ice immediately behind the tongue. 

 Blizzard snows contribute somewhat to its substance, 

 but do not obliterate the deep furrows which form 

 the typical indented margin of the tongue. (The 

 structure of the Drygalski Tongue is referred to in 

 the next section.) 



The Ross Ice Shelf 



This structure has aroused more interest than any 

 other single glacier unit in Antarctica. No colossal 

 sheets of ice of this type are known in Arctic seas, 

 possibly because the temperatures and conditions of 

 snow supply are very different in the north. Little is 

 know^n of the other two large examples, i.e. the Filch- 

 ner Ice Shelf at the head of the Weddell Sea, and the 

 Shackleton Ice Shelf near Mawson's West Base (longi- 

 tude 100° E.). The Ross Shelf occupies the southern 



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