RECONNAISSANCE IX CENTRAL TURKESTAN. 
177 
ridge to the south presents a steep north-facing fault scarp in the central portion, 
although farther west this merges into a fold. 
A peculiar feature of these basins is the drainage, illustrated in fig. 128. In the 
main, the drainage of the Kashgar region is consequent, with the master stream 
flowing eastward toward the center of the Kashgar basin and the smaller streams 
flowing at right angles to it ; but along the line of the smaller basins this simple 
arrangement is interrupted. A continuous valley runs parallel to the main stream 
and north of it, but instead of being occupied by a single stream it contains three, 
A, C, and D, and a fourth, B, taking its rise in the western basin, flows across it. 
The latter stream is easily explained. The tine silts of Kuzzil Oi indicate that the 
up-faulting of the barrier on the south proceeded rapidly enough to convert the basin 
into a lake. This was drained by the short stream B, which has only had time to 
cut a very narrow gorge through the uplifted mass, even though it is composed of 
Fig. 128. — Drainage of the Kuzzil Oi and Min Yol basins. 
the softest of strata. The further study of these basins and their drainage, together 
with the verj' complete geological section exposed near by and the coal mines worked 
b\- the Chinese at Kan Su, offers an interesting field of work. 
The main portion of the Kashgar basin, as is well known, is a smooth desert 
plain. On the edges broad slopes of gravel are soon left behind, and the floor of 
the basin stretches sea-like to the triie horizon. It is composed of horizontally 
stratified sand and silt, entirely free from gravel. The surface is often an immense 
playa, devoid of vegetation and covered witii a deposit of alkali like new-fallen 
snow. In some districts the surface is thickly strewn with dunes, each topped 
with small green shrubs a foot or two high. The latter seem to be the cause of the 
gathering of tlie silty .sand into the dunes, for where the shnibs are dead the dunes 
are being destroyed, and dunes were seen without shrubs, either living or dead. 
Elsewhere the plain of the basin floor is less desert and is covered with a low 
growth of weeds, bushy and tough, from 6 to 24 inches high. The central part 
of the basin, the real sand desert, lay south of my line of travel. In the peripheral 
region the nniddy streams are incised from 10 to 20 feet between slightly terraced 
walls, although all but the largest soon leave their valleys and spread out in playas. 
