CHAPTER XXVI. 
LITTLE KARA-KUL LAKE 
( Contimied) 
I T was not necessary to stay long by the Little Kara- 
kul to perceive clearly its geological formation. I 
soon saw that it was a moraine lake, formed by the 
damming of the valley by the moraine of the Ike-bel-su 
glacier, the remains of which are now pierced by the rivers 
that issue from the lake. The basin, or part of the valley 
dammed by the moraine, is filled with glacier and spring 
water, which bring down with them large quantities of 
sediment, and this, in conjunction with the drift-sand, is 
gradually choking the network of lake streams. The day 
will no doubt come when they will be effaced altogether, 
and the Kara-kul river will flow through the valley in a 
continuously eroded bed. The lake was undoubtedly much 
larger at one time, when the river flowed at the top of the 
moraine, and had not yet succeeded in digging down 
through it. The number of boulders still cumbering the 
bed of the river and lying in its broad mouth — fragments 
of the former medial moraine — testify to this ; as do the 
lagoons just described. That the whole valley was once 
cut off by the now defunct glacier we have unmistake- 
able proof in the number of gravel-mounds, ridges, and 
boulders which lie scattered about on every side. 
“The material, consisting of fine-grained mica-schist, 
crystalline schist, pretty, fine grey gneiss, coarse-grained 
gneiss with felspar crystals, and red varieties of the same, 
etc., is similar to that which I found in the higher regions 
of the Mus-tagh-ata. The gneiss boulders, which are 
spread over large areas, could only be brought thence, 
306 
