A NEWLY DISCOVERED LAKE NORTH OF KARA-KOSCHUN. 171
single mound : the incessantly changing waters of that region have successfully militated against their formation. Due south there was a pretty extensive sheet of water, perfectly open, and to judge from the frequent divings of the wild-duck its depth must have been everywhere extremely slight. Along the shore there were many small silt islands and holms projecting but slightly above the surface. The general impression was that of a veritable marsh. Thus within the short space that intervened between that point, Camp No. CLXVI, and the point where we reached the lake the year before its character was essentially altered. At the former place we found bare, but well-developed, dunes, standing singly; at the latter only one insignificant ridge of sand. At the latter there was an abundance of fresh kamisch; at the former the shore was practically destitute of vegetation. At the latter, the water was fresh; at the former it was so salt as to be undrinkable, except in case of absolute necessity (sp. gr., 1.0052). Hence it may be inferred, that the Karakoschun, the shore of which here extended west-south-west, could not be prolonged particularly far towards the east-north-east or north-east, and that the region in which these waters finally terminated must be excessively desolate. Still the unexpected sterility of the lake-shore may simply be due to the fact to which I have already alluded, that the Kara-koschun is migrating northwards, pouring vast quantities of water over what was formerly dry land, whilst the central parts of the marsh are becoming entirely overgrown with kamisch. If this supposition is correct, and everything speaks in favour of it, the northern shore cannot but be barren, for the water is travelling northwards across the schor desert, and that is of course inherently of absolute barrenness. Hence the kamisch which grew on the older northern shore, now farther to the south, is at this time entirely surrounded by water. It is impossible to trace out and disentangle the changes which the Kara-
r koschun has undergone in respect of expansion, shape, and position in the part of
the Desert of Lop in which it is now situated: not only have the periodic alternations been far too many, but they have obliterated one another's traces. In the vicinity of Camp No. CLXVI we can at all events point with certainty to three different positions of the northern shore — (1) the above-mentioned scarped terrace, north of the existing lake; (2) the shore-line where the kamisch is, and which is to be found somewhere farther south; and (3) the present shore-line, which itself changes at different periods of the year, according as the lake-level rises and falls. Hence it has moved from north to south, and then back again from south to north.
Unfortunately I was prevented from carrying out a portion of my work, and had to abandon some excursions I had planned from this camp, in consequence of an exceptionally violent storm from the east-north-east, which lasted for 55 hours, and immediately after its onset blew with a velocity of 11.5 m. in the second, and soon grew to twice that rate. Shortly before the storm burst, the sky in the east-north-east shot a murky yellow gleam across the desert, but was lighter above the continuation of the lake, from which we may infer that the marsh is prolonged to a pretty considerable distance in that direction. Although the northern shore is accompanied by one insignificant belt of sand, and that is in part held together by vegetation, the storm nevertheless brought with it considerable quantities of drift-sand. Yet very little of it appeared to be arrested there; most of it continued
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