1;6 THE BOGTSANG-TSANGPO.
where it soon comes to an end; it is fed by a spring. In the same valley and protected against the ordinary wind by a projecting mountain, two tents were pitched and flocks of sheep were grazing. The ground is very level and comfortable and consists of fine gravel with some grass and tussocks ; later on there is no gravel but alluvial clay, now hard as stone but soft during the summer, as could be seen from the numerous tracks of ponies, kyangs and yaks. They were sunk deeply into the ground which, during the rainy season, must be rather treacherous.
We approach the opening of a large valley from the S. E. Outside its mouth we cross several erosion furrows coming from the mountainous regions to the N. E. of Nain Sing's route. This great valley is to be found on Pan. 95A, Tab. 16, which also shows the mountains all around the horizon, among them several considerable peaks , of pyramidal or conical form. The region was rich in kyangs grazing in great herds. Camp LXXXI was pitched not far from an isolated mountain group to the north of which the Boatsana-tsanaj5o flowed in an apparently narrow valley.
The march of December 8th is only 8.1 km. Cainj5 LXXXI is situated on a flat threshold, 4,788 m. high, whilst Cam, LXXXII on the river has only 4,707 m.; the fall is as 1 : 100. The temperature of the night was —26.4'; in the morning there was a W. S. W. storm, the whole sky was covered with dark clouds. The soil of sand and gravel is hard and comfortable, with some poor grass. The mountain group to our left consists of greyish red dense albien-limestone, and forms very steep promontories and shoulders with narrow and steep gorges between. The height of this isolated group is only about 150 m. The breadth of the valley may be some two miles. From the camp we rise to a water-parting, so flat that it cannot be noticed ; on its eastern side, however, one feels that the ground slowly falls. There are no erosion beds. The mountains at the southern side of the valley are somewhat higher than on the northern ; and several transverse valleys and gorges open among them. One of them has a spring and is called Teshung. Pa/i-bo is the name of the promontory of the northern group at the very base of which the Bogtsang-tsanapo comes out from a narrow valley piercing the mountains. The river is streaming in capricious beds and has a right terrace, well-marked and 4 or 5 m. high. There are many fireplaces here and several tents are said to pass the summer at Pati-bo. With the terrace to our right, we follow the bank of the river which, as a rule, was frozen over, but open at a few places. At Camp LXXXII the ground is alluvial clay; the grass was tolerable and dung was to be had.
In this region some tents from Ombo on the Dana ra yum-tso are passing the winter, as the grazing near the lake is miserable. The Tibetans from Oiizbo told us that the lake is salt and that no road runs all around the lake on account of the steep mountains at several places. Pilgrims who wander around the lake