THE FERRAR GLACIER 93 



cracks and holes ; this is evidently caused by the deposition of the vapour from the 

 holes as it cooled when escaping into the open air. 



On the evening of December 28th we camped at the foot of a hanging glacier east 

 of Cathedral Rocks (Plate XVIII. Fig. 2), Along the edge of the glacier here a 

 fair- sized stream was flowing, and this stream bi'oadened into a lake in the depres- 

 sion at the foot of the ice-cascade ; and again a few hundred yards below it formed 

 a pond 40 or 50 yards across. The lower lake is full of snow, and appears to have 

 been formed in a circular depression by the silting up of loose snow-drift and the 

 impregnation of this drift with water from the recent thaw brought down by the 

 stream which runs through the depression. This marsh was connected with the 

 lake at the foot of the glacier by one or two deep channels bridged with snow in 

 places. These channels were so deep that no bottom was found with an ice axe ; 

 they are probably partially recemented crevasses acting as drainage channels for 

 the upper lake and the thaw-water flowing into it. 



An interesting feature in these cliff glaciers is that while the ice is constantly 

 descending on to the surface of the Ferrar Glacier below it does not raise any 

 extensive mound of ice there, but is quickly absorbed into the main mass of the 

 glacier, which meanwhile retains the same gently sloping surface as before. 



Another of these cliff glaciers is illustrated in the next figure, which shows the 

 same feature. The phenomenon is on a far grander scale than would appear from 

 the photograph, the distance from the tent in the foreground to the glacier being 

 considerable. The heio-ht of the rock cliffs on either side is of the order of several 

 thousands of feet. 



Such instances speak volumes for the plasticity of glacier ice even at somewhat 

 cold temperatures. Overthrusting alone would fail to account for the rapid absorp- 

 tion of these ice masses into the main glacier. 



On the 30th December the thaw again became powerful. All the ice we 

 traversed was seamed with drainage channels forming an intricate network as far as 

 eye could see on either side of ouv course, and between these channels the surface 

 was honeycombed with boulder-holes, 1, 2, and even 3 feet deep, and full or partially 

 full of water. 



About 2 miles above the ice-falls all the tributary channels within our sight 

 converged into one main channel, along which flowed a stream 3 or 4 yards wide, 

 with a bed of gravelly morainic matter ; this main channel was between 1 and 2 

 feet deep, and had deeply undercut sides. 



From the edge of the ice-falls a comprehensive view of the thaw phenomena was 

 available. Besides the stream already described there was another of equal or 

 superior size to the south of the middle of the glacier, and to the north of it was a 

 series of three streams, each a couple of yards wide, and within 2 or 3 yards of each 

 other. These streams drained the middle of the glacier, and a large quantity of the 

 water they brought down was impounded into fair-sized lakes below the ice-falls. 



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