The rock on both banks was clay-slate, much altered by
heat, often very hard, and with numerous quartz veins;
no more greenstone was observed. The stream, copious
when we started, gradually disappeared as the ravine
widened, and water soon lay only in pools along the
gravelly bed. Boulders of granite were abundant all
along. After three miles the ravine opened into a wide
gravelly plain, skirted by rounded hills of considerable
elevation, to which the alluvial platforms sloped very
gently on both sides. Christolea, a little shrubby Artemisia,
and a small Stipa, were the plants which grew
among the gravel.
, After about a mile and a half, the direction of the
plain trending to the south more than was suited to our
purpose, we turned to the left, to cross the ridge which
ran parallel to it on the north-east. A long gravelly
plain, sloping almost imperceptibly upwards, led us to
the summit of the ridge, which was not more than two
or three hundred feet above the plain we had left. From
this pass, for such it was, though an insignificant one,
an open valley, skirted on both, sides by low rounded
hills, ran to the north-east for nearly five miles. The
appearance of the country was very remarkable. The
hills were all very gentle in slope, and quite rounded in
outline, so that the surface was almost undulating. It
required reflection on the fact that we were traversing a
tract in which the bottoms of the valleys were from
15,000 to 15,500 feet above the level of the sea, to
make us aware of the very mountainous nature of the
country we were passing through, which was, if any
part of Tibet (which I have seen) may be so called, the
Table Land north of the Himalaya. The height of the
mountains, too, was in fact greater than we had at first
been inclined to believe, the gentleness of the slopes making
us think the ridges nearer than they really were, and
therefore leading to a false estimate of their height. In
general they were from 1000 to 2000 feet in height,
and their summits therefore from 16,000 to 17,000 feet
above the level of the sea.
The open valley along which we now proceeded was
remarkable in another point of view. It was quite
waterless, and seemed hemmed in on both sides by hills,
so that its drainage must take place in the direction of
its long axis; at least, no lateral depression could be perceived
on either side. About a mile from its eastern
end, this plain was lower than in any other part. We
had been descending along it from west to east, and we
could see that beyond that point it rose gently to the
eastward. The surface of the lowest part was covered
with a hard shining white clay, without any of the fine
gravel which abounded elsewhere. A few tufts of an
Eurotia were the only plant which it produced. It was
evident that the winter snows which fall on this isolated
spot, when melted in summer, finding no exit, form a
small lake, till they completely disappear by evaporation.
After crossing this low clayey tract, we ascended gently
for nearly a mile in an easterly direction, when the valley
terminated very abruptly and unexpectedly in a precipitous
descent of four or five hundred feet, the clay-slate
rocks emerging suddenly from beneath the gravel at the
very edge of the precipice. The road descended in a narrow
gorge, which had apparently been worn by aqueous