Geological researches in China, Mongolia, and Japan, during the years 1862-1865.

30 GEOLOGICAL RESEARCHES IN
direction gradually ascending, the flat-topped hills of the table-land shutting us in
on both sides, till we reach a watershed from which we look down on a large, deep,
circular valley, covered with grazing herds, and ornamented with the gilded spires of
a lama-temple. This valley is shut in on the north and west by the volcanic formation of the plateau, but its southern wall is of granite and garnetic gneiss, capped
here and there by thin remnants of the plateau mantle. Still farther south, after
passing the village of Yingmachuen the plateau formation predominates, and the
long descent into the valley of the Te Hail is entirely over its rocks.
The great depression of the Te Hai is about twelve miles broad, and so far as the
plateau is concerned, appears to be open to the S. W. in the direction of its longer
axis. The northwestern side is formed by a serrated range of mountains, which
rises about 2,000 feet above the lake, between this and the plateau. The eastern
wall is of gneiss capped with the volcanic plateau formation, and the same would
seem to be the case with the southern wall, while, as we have seen, the northeastern
side is volcanic in its entire height. Thus the thickness of the volcanic mantle
varies, within a few miles, several hundred feet.
The northeastern end of the valley contains an extensive deposit of the terrace
loam. This faces the lake with a bluff that stretches N. W. S. E. across the valley.
From this line the terrace rises toward the N. E. at first gradually, and then
rapidly, until in the long northeastern arm of the valley and in the side valleys, its
surface is several hundred feet above the lake.
Below this terrace a plain rises gently from the lake toward the mountains.
The terrace deposit is a firm, stratified loam, containing, near the hills, numerous
fragments of the neighboring rocks and layers of gravel. It is cut into by deep
ravines, in the sides of one of which, about five miles east of the lake, I found
several species of fresh-water univalves.
The lake is apparently about eight miles long by four or five broad. Its water
is salt, though far less so than seawater, and is not bitter. The flat surrounding it
is covered with a thin coating of soda efflorescence.2
While the valley of the Kir Noor is occupied exclusively by the Mongols and their
herds, that of the Te Hai is cultivated by Chinese, only one or two Mongol camps
being seen. Ancient watch towers, that dominate these plains, and from which
signals could be made to the long line of similar posts on the Great Wall, are silent
monuments of a time when the shores of these lakes were the home of an aggressive race, ever threatening a descent into the fertile regions of China. Rising with
the terrace, the road leads us to the hills that form the southeastern wall of the
valley, and we pass through these by a deep and rocky ravine, in which the pass is
situated. These hills are, as I have already said, of gneiss, characterized by an
abundance of garnets, and capped with the volcanic mantle. The stratification
trends, in the main, N. E. and dips 75~ to N. W. Garnetiferous granulite, from these, Daikha Noor of the Mongols.
X For negative results of a microscopical examination of the deposits, both of the terrace and the
flats, see Nos. 2 and 3, in Mr. A. M. Edwards' Letter, Appendix No. 3.