PHYSIOGRAPHIC OBSERVATIONS. 145 
whole has tlie appearance of a mouutaiu iiiiiss formerly normally dissected above 
water and now flooded in the lower portions. These observations tend to show 
that when the normal dissection of the flooded part of the peninsula took place the 
lake stood far below where it is now, and possibly did not exist at all. It was then 
raised to tlie old high levels, and must have remained there a long time, for the 
shores, though now in many cases obliterated, are broad, even where cut in steep 
ledges. Then it fell again, and a relatively long time afterwards was raised to about 
the 150-foot lev^el, where it remained some time and then graduall)' receded, leaving 
its fresh shores following in and out of the old peninsula valleys. The lake surface 
appears to have stood at its present height for but a relatively short time, for its 
shores show very little cutting from wave action (fig. no). 
Considering all facts about the Kara Kul basin, we see that, although there 
is no absolute proof for associating the old shorelines of the lake with the glacial 
advances, they naturally group themselves together by probability' ; for if Kara 
Kul exists as a result of moraine damming and if, as seems more than likely, ice 
epochs occurred during times of increased precipitation, the greater fluctuations of 
lake level were doubly controlled by glacial epochs. Moreover, the ancient 300 to 
400-foot shorelines are in their imperfect state of preservation similar in antiquity 
to the old deeply clay-buried moraines, and the shorelines marked from about the 
150-foot level down are similar in their freshness to the overriding moraines with 
their unaltered surface topography. As further evidence we have the fact that the 
overriding moraines are cut, where they extended suflliciently low down, by the 
150-foot and lower shores, but not cut by the 200 to 320 foot and higher levels. It 
therefore seems proper to state that the lake surface appears to have risen to a 
height of 320 feet or more during the first glacial epoch established and to a height 
of about 150 feet during the second glacial epoch established. 
GLACIAL EPOCHS. 
It seems only reasonable to suppose that epochs of increased glacial conditions 
were coincident on both sides of the Trans Alai range and in neighboring regions. 
In the Great Alai Valley and on the Pamir we have one class of moraines of 
similar antiquity and extent, another of similar freshness and e.xtent, and indications 
of a third still later class of little extent. Evidence thus places each class on the 
Pamir as contemporary with its respective similar class in the Great Alai Valley. 
To distinguish the two definitely established glacial epochs we may name the 
older one the Alai Epoch and the later one the Kunundi Epoch. It is therefore 
at present convenient to divide Quaternary- time for the field in which I worked 
into five parts — 
f Post Kurumdi. 
I Kurumdi Epoch. 
Quaternary \ Orogenic Epoch. 
I Alai Epoch. 
I Pre-Alai. 
