PHYSIOGRAPHIC OBSERVATIONS. 143 
fresh. The moraine front forms an irregiilar, steep slope rising from the plain some 
distance below, and about a verst to the north of Kotir Kul. Starting at the 
base of the moraine, the plain inclines north to Kizil Kul (fig. 107). 
OBSERVATIONS IN THE REGION OF KIZIL KUL. 
Kizil Kul, as the upper portion of the Markan Su stream is indicated on the 
Russian io-\'erst map, is not really a lake, but simply a sluggish portion of the 
stream. Here the Markan Su heads in three branch streams, all of which run on 
broad plains of clear gravel, broken at frequent inter\'als on their borders b}- large 
fans of angular material. These plains join to fonn the more e.xpansive stepjie 
around the upper portion of Kizil Kul, and in the midst of this steppe a ledge 
mountain about 500 feet high rises sharply from the waste. 
From the midst of the various branch plains there rise numerous island tops of 
moraines, with apparenth' unaltered surfaces and slopes pitching sharply under the 
alluvium, while the valley sides themselves appear to be partially buried by the 
waste. There are, also, several ledge islands in the midst of the branch flood plain 
Fig. 108. — The valley heacling a little west of Kizil-Art and joining the Kizil Kul Steppe. 
coming down from just west of Kizil-Art pa.ss (fig. 108). Thus this whole region 
has the appearance of a deeply-carved valley system partialh- buried in waste, much 
of which must have accumulated since the dumping of the moraines, probably of 
the overriding class seen in the Kara Kul basin. There are also traces of low 
terraces contouring the slopes bordering the Kizil Kul depression, and remnants of 
an ancient plain to be seen sloping back in a gently rolling topography above the 
steep valley sides and on the ledge island some 400 feet above Kizil Kul. 
On a side excursion about 5 versts to the southeast of this point I came in 
view of a larger glacier a few versts to the east and flowing south from the Trans- 
Alai. Unfortunately there was not time to visit it, and the bad sand-storm that 
came up made it useless to take photographs. Through the field-glasses enough 
was seen of its long ice-flow to show that it that it might be an important point 
of attack for the glacial geolog}- of this region. 
FLUCTU.\TIONS OF L.\KK LEVEL .\ND GLACI.\L ADVANCES EXPLAINED BY 
CLIMATIC CHANGES. 
With the little time available it was hardly possible to make sufiicient obser\-a- 
tions to definitely pair off the glacial advances with the old shorelines of Kara Kul. 
It can, however, be stated that during each wet period the lake rose either till its 
