国立情報学研究所 - ディジタル・シルクロード・プロジェクト
『東洋文庫所蔵』貴重書デジタルアーカイブ

the fact that the Satlej and its tributaries run more in solid rock in the eastern parts
of the plain, and more in soft alluvial matter in the western parts.

Beyond the Gunda Yankti some 4 miles more of the plain brought him to
Darma Yankti, which was larger but similar in character. For the two last days
to Gyanima the plain was level or gently sloping, covered with shingle. The abrupt
rocks around or rising from the level of the plain suggested that he travelled over
a dried-up bed of some great lake or inland sea. As his brother Henry, he was
told that from the lower end of the Gyanima lake a stream issues and joins the
Darma Yankti, which soon afterwards unites with the Gunda Yankti, after which
the combined river is called Chu-kar. East of Gyanima he enters a hilly country
forming the eastern boundary of the plains of Guge. He thinks the deposits of Guge
have been formed by the ocean. The valleys east of that plain show that they have
carried much more water in olden times.

The watershed of Rakas-tal was found to be 15,200 feet, or 200 feet above
the lake. Here for a short distance he touched ground where his brother had been
in 1846. But Henry Strachey went north, Richard Strachey and Winterbottom south
of Rakas-tal. On the way to this lake eruptive rocks were found and on the south-
ern shore hypersthenic rocks predominated. The Tibetan name of the lake was found
to be Tso-Lanak. As his brother, he calls Gurla, Momanangli.

His plan was now to go to the north-western corner of the Manasarovar,
where the point of efflux of that lake was supposed to be. This we were anxious
to see, for Moorcroft had denied the existence of any opening there, though
my brother had crossed a large stream some miles to the west of Ju, which he was
informed came from Manasarovar.

He had hoped to be able to go along the edge of the lake, but when he
came to a little shingly bay, the steep cliffs forced him to ascend again over the
hills, where the ground in parts was almost level. On September 16th he proceeded
14 miles from Rakas-tal to the Manasarovar. At the commencement of this day's
march hypersthenic trap was still found, after which followed mica schists, and frag-
ments of granite. He is not sure whether any granite in situ was crossed, but
Gurla seemed in great part to consist of granite.

He made the following observations on the isthmus:

¹The ground separating Manasarowar (Mapham) from Rakas-tal rises rather steeply to
about 300 or 400 feet above the level of the lakes, being apparently altogether composed of
alluvial deposits made up of pebbles, precisely similar to those now found on the beaches of
the two lakes, of granite, mica schists, and quartzites, sometimes cemented together and forming
conglomerates, but more commonly in the state of loose gravel. The general structure of this
alluvial mass is so perfectly identical with that of the deposits of the great plateau that they
must all be held to have had a common origin; but it is impossible to offer any opinion as to
the probable time at which this particular portion assumed its present position relatively to the
rest, whether before, with, or after the general movements that have elevated the whole. —
We kept for some distance along the top of the separating ridge, till a hollow that nearly