During the whole night, a strong wind had been blowing and the minimum temperature was only -2 3.9°. But from I o o'clock a. m. the atmosphere was in an equilibrium that is very rare on the Chang-tang.
From Camp LXXIV we go south with the base of the eastern mountains near our left and the chief watercourse of the valley at our right. The mountains are pierced by innumerable gorges and erosion beds directed to the river. As the road follows an old terrace about 2 0 m. above the river, and as this is also pierced by all the small tributaries, we have to cross them all, which makes this part of the road very tiresome. Several of them have perpendicular sides a few meters high and to avoid them the road goes in a zigzag. Outside the mouths of some bigger gorges and tributary valleys, conical fans have been formed on which the beds of the watercourses have divided themselves in many delta-branches. All the beds are full of gravel. Everything seems to indicate that we have reached a region with more precipitation than those parts of the plateau-land which we have left behind. Probably during the latter half of the summer, the monsoon rains reach these regions. In one of the larger tributary valleys, there is a little brook, from a spring, forming ice-sheets. In the bed of the main brook itself the ice-sheets are very extensive and there are several small islands in the ice. Here the right terrace of the principal brook is well-marked and about I o m. high, somewhat rounded and pierced by innumerable gorges of the same kind as on the left side. At the latter, the terraces grow lower and finally disappear. To the right or western side of the valley the mountains retreat gradually, are more interrupted, and different groups of them are, here and there, separated by small plains.
Finally our valley opens out into a large plain or arena-shaped steppe with hard comfortable soil of fine gravel with small sparse plants, which, however, come to an end in the lowest part of the depression, and with rabbits' holes which also become more and more rare. The Tibetan road turns S. E., but we leave it and march southwards in the direction of a few black tents. The plain still falls to the south. It is full of tracks of tame animals and of kyangs. Flocks of sheep are visible among the hills to the west, at a great distance. The bed of Niring-tsango becomes broader and turns more and more S. E. to the lake bed of the depression. At a point east of the river bed, I observed a height of 4,490 m., which is even lower than the altitude of Camp LXXV, though the latter, 4,503 m., is more reliable. When we crossed the bed it still contained some ice. The lake bed, which was left at some distance to the east, seemed to be dry now and filled with deposits like those of the previous depressions. To the S. S. W. there appeared another greenish white bed, which is the continuation of the dying lake. There, springs came up. The depression is oblong from east to west and may perhaps be regarded as a part of a latitudinal valley. On all sides it is bounded by fairly low mountains of violet,
IIIFカラー高解像度
