2IO EXPLORATIONS IN TURKESTAN. 
curve without a trace of terracing or any indication of old lake shorelines. Here 
and there, however, the smooth stretches of the swamp are broken b}' low, rounded 
hills or by broad, flat tables, 20 to 40 feet high and several miles wide, which are 
distinguished by a sparse growth of knotted poplar trees. On the soft slopes of 
these elevations are found most of the springs that make it possible for the poor 
Kirghiz to inhabit the wretched swamp. Jai Tebeh (Devil Hill), at tlie western 
end of the lake, is one of the best examples. Here on the sides of a small rounded 
hill five small springs bubble gently up at heights of from 10 to 40 feet above the 
green swamp which stretches for 3 or 4 miles on every side. The material of the 
hill and of the swamp seems to be identical, although possibly that of the hill is a 
little more sandy. In neither is there the least sign of gravel. A few miles west 
of Jai Tebeh a fonnation of apparently the same sort as tliat of the hill assumes 
the shape which has above been called a table, although it might better be described as 
a low and xer}' broad promontor}'. It rises from the swamp as a rude terrace with 
an irregularly dissected front, on which there is a suggestion of smaller terraces. 
Near the borders the top is somewhat rough, but it soon becomes very even and 
stretches back smoothly toward the mountains, near the base of which it merges 
into the slope that rises more steepl)', although still ver}^ gently, toward the 
mountains from the edge of the adjacent swamp. On this low promontory- are 
two or three springs like those of Jai Tebeh. A few miles farther to the west, at 
Dongjigdeh, another hill stands in the middle of the portion of the swampy plain 
lying west of the lake. The hill is about 40 feet high and has a spring near the 
top. Like Jai Tebeh, it appears to be mostly made of silt, but there are gravel and 
some sand scattered here and there. Six other streams were seen in different parts 
of the basin, welling up on small hills at a height of from 20 to 30 feet above the 
surrounding swamp or neighboring lake. In all the springs the water was sweet, 
and the material from which they flowed was the same silt as that of the swamp, so 
far as the eye could detect. 
It seems hardly possible, however, that the underlying j^art of these hills can 
be composed of this same silt. The one hill where sand and gravel occur seems to 
furnish the key to their structure, and the suggestion afforded b}- this one is borne 
out by evidence which will be presented after the statement of the conclusion to 
which it leads. Shor Kul appears to have been twice expanded to a size much 
greater than that of to-day. At the first of these expansions it reached a height of 
about 350 feet above the present water level. It then retired, so that the lake 
deposits were first covered with sand and gravel and later were well dissected. It 
next rose again, although to a less extent, and covered some of the remnants of 
the old lake deposits with a new layer of silt (fig. 146). The remnants of the 
old deposits are the hills and tables which have already been described, and which 
are now left exposed by a second retreat. The springs occur on them because 
the layer of sand and gra\-el on top of the earlier lake beds is easily pervious to 
water, while the silts above and below are impervious. Consequently water from 
the base of the mountain beyond the end of the silts gathers in the sand or gravel 
and percolates gently downward toward the lake. In the little hills the upper layer 
