Southern Tibet : vol.4 / Page 282 (Color Image)

0282	Southern Tibet : vol.4

granulated or knotty, overgrown with low grass and perforated by innumerable
rabbits' holes. The northern ridge, as may be seen on the panorama from *Camp
LXXXII*, is more continuous and has very steep rocky slopes. A little transverse
valley pierces them, opening to the N. 7° W. on the last-mentioned panorama. The
scree of gravel and débris at the base of the southern mountains reaches the vicinity
of the river, and one of them, with hard barren ground of fine gravel, projects
farther than the rest and is crossed by our road. The plain part of the valley may
be one mile, or a little more, broad. At intervals we touch the south-going bends
of the river. The ice-sheet of the river is concave and broken up at the banks,
proving that the volume of water decreases gradually during the winter. In 1901
I had found much more water in the *Bogtsang-tsangpo*, but then the season was
earlier or in the first days of October. The river is almost entirely fed by springs,
which get completely frozen as soon as the severe cold sets in. It is the rains of
late summer that again brings life into the springs, and they are very numerous in the
valley of this river. The *Bogtsang-tsangpo* may be regarded as a recipient of the
water of innumerable springs. After rains it receives direct affluents. Some springs
do not freeze even during the coldest part of the winter and if they are not too
far from the river, their water reaches its bed. Probably some water keeps running
during the whole winter under the ice-sheet. Now the volume was only about
1 cub. m. a second at *Camp LXXXII*, but increases slowly down the course on
account of new tributaries. East of this camp we passed a spring the brook of
which did not freeze until some 50 m. below its beginning. It formed a pool covered
with ice, but from there continued to the river. The right erosion terrace is always
clearly visible, though sometimes rather low; at *Camp LXXXII*, for instance, only
2 m. Farther on, at a new bend of the river, a little partly open brook goes out
to the river which here is open for about 100 m. along the right bank, though only
to a breadth of 1 m.

Then we cross the plain at some distance from the river which disappears
from sight. But sometimes we ride over old abandoned beds, some of them dry,
others containing ice-sheets, but no water. On account of the levelness of the ground,
the river seems from time to time to change its bed. The river sticks to the northern
side of the valley which is due chiefly to the screes from the southern mountains.
Between their base and the base of the northern mountains the profile of the valley
here forms a straight horizontal line. In this plain part of the valley the ground
consists of clay and alluvium without a single stone.

*Camp LXXXIII* was pitched at a branch of the *Bogtsang-tsangpo* which
seemed to be cut off from the main river with the running water. The latter pro-
bably turns to the N. E. just at the eastern base of the *Patu-loma* mountain group.
The panorama, 99A and 99B, Tab. 17, was sketched from *Camp LXXXIII*. To the

National Institute of Informatics - Digital Silk Road Project
Digital Archive of Toyo Bunko Rare Books

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National Institute of Informatics - Digital Silk Road Project Digital Archive of Toyo Bunko Rare Books

Citation Information

OCR Text

National Institute of Informatics - Digital Silk Road Project
Digital Archive of Toyo Bunko Rare Books