350 TERI-NAM-TSO.
has a quiet current without rapids. Its valley is open and about 4 km broad, between low mountains. The road keeps to the right side without crossing the river once. The erosion terraces are sharply developed and some 1 o m high. As a rule it is easy to distinguish them from the old beach-lines, of which the highest follow the mountain sides above the sharper erosion terraces. Like the Dangra-yum-tso the Teri-nam-tso, during the pluvial period has covered an area twice or perhaps thrice as great as the present stream. At Camp 414 the highest beach-lines are quite 20 m above the bottom of the valley. The bed of the river is very broad and flat, and the river usually divided into several shallow branches. The bottom of the valley is covered with tussock grass and gravel. Just in the bend where the road turns from S.W. to south, a great latitudinal valley joins from the west; it has a road to Chokchu, N.E. of Teri-nam-tso. The rock is quartz-porphyry. At Camp 414 a valley Sha or Ya enters from the S.E., opposite the Camp, to the N. 65° W., the mountains are called Me-ri or Men-ri; in the immediate neighbourhood, N. i 2° E. is a conical rock called Nagräng.
At Camp 414 three different names were given for the river: Soma-, Nyagga-, and Soing-tsangpo. The river carried about 12 cub. m and was divided into three shallow branches. The bed was some 30o m broad and is under water after heavy rains. At the end of July the Soma-tsangpo is usually at its highest and remains high for three months, but may be crossed at some well known fords. Seven or eight km direct south from Camp 414 the valley is seen coming from the S.E. Between Camps 407 and 408 we had crossed it at a height of 4 792 m giving a fall of 108 m down to the lake. After its long run westwards the river pierces the ranges we had crossed in Dongchen-la and Teta-la. These ranges belong to the Transhimalaya and have a general direction E.S.E. —W.N.W. About their continuation, beyond the transverse valley of the Soma-tsangpo nothing is so far known with certainty; it is, however, probable that they continue with the same general direction north-westwards, where the Ladung-la may be situated in one of them. On the other hand, many of the ranges in this part of Tibet are very short and interrupted. Here is one of the places where it may be difficult to draw a sharp boundary line between the Transhimalaya and the next system to the north.
IIIFカラー高解像度
