470 THE CENTRAL ASIAN DESERTS, SAND-DUNES, AND SANDS.
on loth September 1899. It consists of fine, light-grey sand of quartz, mica, felspar, and hornblende, and is strongly calciferous, with a moderate proportion of magnetite.
. A specimen from the Jarkent-darja at Kuruk-asti (taken on 2nd October 1899) consists of grey calcareous, argillaceous dust, with no perceptible traces of magnetite. A specimen of 7th October 1899 from the bottom of the Tschöl-köl consists of grey argillaceous powdery sand, strongly calciferous, but with only slight traces of magnetite. Owing to the connection that exists between the Tschöl-köl and the Sorun-köl, it may be assumed that this specimen contains only a small proportion of river mud, the greater part consisting of drift-dust and drift-sand, which have settled in the lake. A specimen taken out of the bed of- the Jarkent-darja on the 16th October consists of fine light-grey. sand, _ though only a. few; grains of mica and gypsum are coarser than o.5 mm. The rest, consisting of quartz, mica, and felspar, is much finer. It is moderately : calciferous and has a • very, heavy proportion of magnetite. Another specimen from the bed of the Jarkent-darja, taken on the right side, at Matan, on 24th October, consists of very fine, brown-grey, calcareous sand. On 2nd November I took immediately below Läschlik, at the confluence of the Karakirtschin with the Tarim,: a specimen of grey clay, highly calcareous.
On 6th November I took out of the Tarim at Bostan the following specimen of the mud at the bottom — a yellow-grey, very fine sand, consisting of quartz, felspar, mica, and hornblende, strongly calciferous, and with a very heavy percentage of magnetite. On the same day another specimen was taken a little lower down, at Kara-daschi, which possesses essentially the same properties as the former — light grey, very fine sand, of quartz, felspar, mica, and hornblende, moderately calciferous, and with a large percentage of magnetite. A specimen from below the mouth of the Intschikä, taken on 14th November, is grey argillaceous dust, moderately calciferous, and with no perceptible traces of magnetite. From Mungusasti, on the 23rd November, comes a fine yellowish sand, the grains less than 0.5 mm., consisting principally of quartz, mica, and felspar, strongly calciferous, and with but slight traces of magnetite. Lastly a specimen from the bottom of the Tarim on 2nd December 1899 — very fine sand, yellow-grey, moderately calciferous, and with a moderate proportion of magnetite.
The places from which these specimens were taken are too few and too wide apart to justify any general conclusions. For such conclusions we require a regular series, with precise data as to the local relief and the velocities of the river. It would also be very important to know whether each specimen were taken from the alluvial or from the eroded side of the river.
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