Geology 



be required when we reached the glaciers, of which we 

 could now get occasional glimpses. 



Owing to the roughness of the ground we were 

 unable to travel more than fifteen miles per day, and on 

 some days this was reduced to seven or eight, when we 

 had to traverse moraine-covered country. 



There was little of interest in the next section of 

 the valley, though we were able to locate two further 

 quartz-porphyry dykes of considerable size, both of which 

 contained a few small crystals of tin-stone and tourma- 

 line, but not in sufficient quantities to pay for working. 



When within about two days' march of the foot of 

 the glacier, we noticed, on an outlying spur of the hills 

 on the north-east side of the valley, three curious 

 cuttings, one above the other. They seemed to connect 

 the near side of the spur with the valley of a tributary 

 stream which lay beyond it, and had a strangely artificial 

 appearance. On climbing up to these we found that 

 they were large trenches with precipitous sides and flat 

 floors. They were obviously the work of running water, 

 but were entirely streamless, though each had a great 

 spread of gravel covering the hillside at its lower end. 

 Under existing conditions there was no possible catch- 

 ment for a stream in such a position, and hence we 

 concluded that they were the overflow channels of a 

 lake which had occupied the valley of the tributary at 

 a time when its mouth was closed by the ice of the 

 glacier in the main valley. 



We made careful measurements, by means of our 

 aneroid barometer, of the relative levels of the upper, or 

 intake, ends of the three channels, and found that they 

 were 830 feet, 745 feet, and 690 feet respectively, above 



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