A TRIP TO ANDERE-TEREM. 373
the north of it are traversed by the rivers Kara-muran, Möldscha, Bostan-toghrak, Tollan-chodscha, and Nija-darja, some of these being at times very respectable streams, although, like all the rivers of East Turkestan, they are undergoing a process of shrinkage. In former times they were all bigger and watered more plentifully the region in which vegetation is growing; though this is now dying out and thriving ill, and will no doubt in due time be overwhelmed by the sandy ocean advancing from the north-east. The strip of fresh grazing which lies at the foot of the detritus slope of Kirk-saj, and on which the taghliks, or »mountaineers»,'graze their sheep, is mainly watered by rain, and some smaller streams. Below this strip of grazing comes the saj, which possesses every condition requisite for the formation of a desert — refractory soil, hard gravelly débris, and scanty precipitation. The rivers I have named, although they cut their way across this belt, do not in the slightest degree do any-
Fig. 323. A CARAVAN OF MERCHANTS FKOM KERIJA, TRAVELLING ON THE »ASTIN-JOL».
thing to water it, for they have excavated for themselves such deep and well-defined channels that, even when they rise exceptionally high, they are unable to overflow, and so confer benefit upon, the adjacent districts. The water flows as it were through underground drains or conduits, and the saj derives not the smallest advantage from it, and consequently remains barren. The same thing is true of the belt of dunes which lies below it; for although the rivers there flow along shallower beds, they are of no service to the soil. But in the belt of vegetation beyond the astin-jol the case is quite different: there the river-beds are barely sunk below the level of the general surface, but spread themselves out in a deltaic manner, and so moisten the ground, which has an extremely gentle inclination towards the north. It may be assumed, that when these streams carried bigger volumes than they do to-day, there was in this part of the country a very extensive forest, which effectually kept the desert at bay. Perhaps the belt of vegetation which we crossed in the middle of the Desert
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