IIIFカラー高解像度
国立情報学研究所 - ディジタル・シルクロード・プロジェクト
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| IIIFカラー高解像度 |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.3 | |
| 1899-1902年の中央アジア旅行における科学的成果 : vol.3 |
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引用情報
FROM THE KUM-KÜL OVER THE ARKA-TAGH.
419
the cooking-pot, exactly like the hills and heights which I have already described as existing in another part of Eastern Tibet. Even if there ever did exist any stratification or bedding it is certain to have become obliterated under the circumstances that prevail. After a continuous downpour, especially of rain, though it is also true of melting snow and hail, the whole of this slough of despond — it is by no means thick — becomes wet through, and then, in consequence not only of its own weight and the very slight degree of adhesion that subsists between its finest particles, but also of the softening and loosening effects of the water upon the surface, it must inevitably begin to slide down, at however slow a rate. From the summits of the hills, where the thickness of the formation as well as its weight are greatest, the pressure is propagated outwards, giving rise to a displacement and an extension all round. This movement and transference within the body of the mass take place extremely slowly, and become more and more retarded in proportion to the increasing flatness of the hill or ridge. In their present stadium the heights of Min-bulak are so small and so low, that the sliding movement is at a minimum, and exercises no noticeable effect upon the regularity and hydrographical position of the innumerable eroded rills, torrents, and watercourses. But it is easy to imagine these gullies, as a consequence of a sufficient sliding action or displacement, to be prevented from excercising their functions in the usual way.
It is however ruinous to a caravan
to attempt to travel across a country such A
as that. We were forced to turn back
and retrace our steps down the glen, al- /
though its bottom had been trampled still softer by the camels. At length we turned
west up a side-glen, the scarped terraces of which, consisting of the same soft material, were about 3 m. high and perfectly vertical (fig. 329). Once or twice, when we had to cross over it, our only alternative was to hack out steps on both sides with spades and pickaxes. In this glen there was no water, but it is nevertheless bordered by a number of contributory crevices of a peculiar shape; that is to say, they are often 1 dm. wide and 1 m. deep, or ten times deeper than they are wide. Crossing over an unimportant pass (alt. 4171 m.) in the neighbourhood, we reached a flat cauldron-shaped glen, surrounded by the usual low gentle hills, with a small pool in the middle of it. Its surface had a sprinkling of grass, and the meadows were traversed by a couple of small brooks, which ran off towards the north-west; this was said to be the actual Min-bulak.
Thus during the course of this day's march we came across no actual hard rock; the nearest approach to it was occasionally fine gravel and coarse sand lying on the outsides of the gentle hills. The only place where the bedding was distinct was on the hills immediately south of Camp XIV, the clay there being rather firmer, although even it crumbled readily between the fingers. Its dip was 45° towards the S. 3° W. One or two of these hills presented the appearance shown in fig. 330; one of them was covered with a layer of sand and gravel. Some grass grew on them, although very scantily and of very poor quality. All the country next to them on the south was perfectly soft and absolutely barren.
Fig. 329.
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