SIKHIM AND BHUTAN
it is, with gneiss moraine débris, the mountain itself being shale.
All along these mountains there is everywhere evidence of the former enormous size of all these glaciers, both on the north and south. To the north, moraine débris is found fifteen to twenty miles within Tibet, and boulders of gneiss are found on limestone hills with nothing now but huge flat plains between them and the peaks of the Himalayas. To the south, along all the valleys, old lateral moraines extend for many miles and in many places are quite distinct, 1000 feet to 1500 feet above the present river level. It seems almost impossible to take in the fact that these valleys were once filled with ice, or to imagine what these mountains were like in former days, as the moraine débris now showing, would by itself form mountains as high as those we have in England without taking into account the enormous quantites of silt carried down by the rivers during these ages.
The rainfall in these parts is very heavy, and this very great alteration in the glaciers can, I suppose, only be accounted for by the gradual change of temperature, although theoretically, in accordance with the scientific opinion held by many authorities, that the Himalayas are still being elevated by the contraction of the earth’s surface, the mountains must in those days have been more massive if individual peaks were not higher. From this point we had a splendid view of the Bam-tsho and Yeum-tsho lakes, of which I had known for some years, but had not seen before, with Chomolhari in the background, standing up splendidly against the blue sky. The panorama of interminable ranges in Tibet was also very impressive, although gloomy, and I wished I could march into the then forbidden land.
The survey of this portion of the boundary finished, I returned to Thangu in order to reach the Lonak valley viâ the Nangna-la. It was a very roundabout, and very difficult route, and took several days longer than if I had
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