THE HEART OF THE ANTARCTIC 



The debris being mostly of a dark colour the amount 

 of thaw in summer is considerable, and the whole district 

 is seamed with stream-channels which, during the few 

 sunny days in the height of summer, are filled with run- 

 ning water. Every basin-like hollow between the ridges 

 and peaks is filled with a lake corresponding in size to 

 that of the hollow. In spite of the loose nature of the 

 debris the lake basins are enabled to hold water because at 

 all periods of the year the ground at a depth of a few 

 feet is frozen hard. Even in summer, the whole mass 

 of the debris, except an outer mantle, is firmly cemented, 

 in consequence of the freezing at a slight depth of the 

 percolating water supplied by the melting snowdrifts. 



Proof of this is seen where the streams have cut fairly 

 deep channels in the moraines. In the walls of these 

 channels lenticles of opaque ice fairly free from gravel 

 and varying from an inch or two to a couple of feet in 

 thickness are to be seen in many places, while in other 

 places, if a few feet of the outer mantle of the stream- 

 cliff are removed, the gravel behind is found to be firmly 

 cemented. 



Most of the streams run northwards, and at the 

 northern end of the moraines quite a thick alluvial deposit, 

 having a strong resemblance to a series of miniature deltas, 

 is to be seen along the ice-foot, awaiting subsequent re- 

 moval to the sea. The amount of material removed from 

 the moraines in this way must be very considerable. 

 Another agency which must be fast reducing the size of 

 the moraines is the direct heat of the summer sun on the 

 cliffs at the northern end. Frequently while we were 

 camped near the moraines small avalanches of gravel and 

 mud fell on to the ice-foot, and many tons of material 

 brought down in this manner must be carried away when 

 the ice-foot breaks up in the late summer months. The 

 wind also plays an important part in the transport of finer 



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