is a small accumulation of sand, but there is not even a rudimentary formation of dunes. The colours are bright: the brilliant yellow grass, the clear blue sky, the dark violet, greyish yellow and red mountains, the white snow-caps on the highest summits, and the black rocks below the snow.
The grass comes to an end and the ground is then covered with fine, black gravel. One of the transverse valleys to the north is considerable ; its dry watercourses, however, are very diflùsed. Where we again reach a branch of the brook the grass is abundant, and the bed has a very low and rounded erosion terrace. On its other side there is barren sand with ripplemarks, but no dunes. Clay ground is also common. This alluvial region is curious. Wherever one goes there are signs of running water but the branches of the brook are meandering in all directions and in very undecided beds. Sometimes one gets the impression that the whole central part of the valley, to a breadth of several kilometers, is the bottom of a dying river, of which now only a few scant watercourses remain. Finally the ground consists of yellow clay covered by coarse sand or fine gravel of quartz grains of 4 mm. diameter as an average. This sand is arranged in great ripplemarks with a distance of from 1 dm. to 1 m. between the waves. The latter have obviously been formed by very strong winds, but they still show no tendency of accumulating into dunes. Now being moist, they were immovable. From Camp XI the chief branch of the brook seems to be situated near the foot of the southern hills, though the distance to them may still be considerable.
Panorama 26A and 26B, Tab. 5, is morphologically of exactly the same type as the preceding panoramas, though the open gap in the east marking the continuation of the latitudinal valley has dwindled to a very narrow space depending upon the configuration of the projecting spurs from the mountains north and south. Comparing the panorama with the map it seems as if this open gap ought to have been situated a little south of straight east, or about S. 8o° E. The disagreement is caused by the corrections inflicted on the map from the astronomical points and from the topographical knowledge previously possessed regarding the country in general. I am sure that the bearings of the panoramas are more reliable than these corrections. In another part of this work Colonel H. Byström has discussed the great difficulties he has had in constructing the map of 1: i,000,000 on account of the discrepancies existing between the itineraries of different explorers. In connection with this observation it may be said that the panoramas give a much clearer idea of the mountains than the maps. In the former there cannot be any greater errors in the bearings than i or 2 degrees. When, in the future, the astronomical points will be duly corrected, and the situation of Tibet as a whole well fixed within the net of coordinates, the value of the panoramas will increase. The scientific conquest of this country will still take centuries.
IIIFカラー高解像度
