172 
EXPLORATIONS IN TURKESTAN. 
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bounding a flood-plain so narrow that in the valley bottom a road with difficult}- 
finds a place among the cedars and mnst often cross the cascading brook or even 
climb out of the valley. Between these young valleys the graded northern slopes 
of the broad anticline are covered with cedars, which form the 
only forest seen during the whole journey. Far up the stream, 
where glaciers have been at work, the valleys widen and are 
better graded, and at the same time the interstream areas become 
rougher, although they still contrast strongly with the valleys. 
The }outh of the latter is shown not only by the steepness of 
the walls, but by the relatively moderate depth, i,ooo or 2,000 
feet, which seems to be the most that they have as yet attained 
beneath the interstream highlands, although the streams descend 
very rapidly and are cutting actively. Another evidence of youth 
is seen in a nonnal hanging valley from which a small side stream 
cascades 40 or 50 feet directly into the Jukiichak Su, whose 
narrow valley here has no flood-plain whatever. 
The broad ridge which lies along the northern border of the 
Tian Shan plateau is always covered with snow, and most of its 
passes are occupied by glaciers. A few of the summits have 
been sharpened into peaks by glacial action — after the fashion 
described for Alpine peaks by Richter — and are worth seeing as 
attractive examples of Alpine scenery, but most of them are 
mere remnants of the old peneplain, separated by broad, but not 
very deep, valleys of glacial origin. The uniformity of summit 
height is illustrated by the excellent topographical map con- 
structed by tlie Russian general staff" on a scale of 2 versts 
(iy2 miles) to the inch. Out of 43 summits, of which the 
elevation was given on three contiguous sheets at the eastern 
end of Lssik Kul, 32 reached an elevation of from 13,000 to 
14,000 feet, and the highest reached 15,069 feet. 
As soon as the broad ridge of the northern border is crossed 
the country assumes an aspect which fully justifies the tenn 
" plateau." At Jukuchak pass, for instance, the narrow young 
valley which one ascends in traveling southward from lssik 
Kul is exchanged for a broad, open, elevated plain, bounded 
on all sides by snowy mountains, whose slight dis.section 
causes them to suggest a block of marble on which the sculptor 
has rudely outlined a form but on which he has as yet carved few 
details (see fig. 1 25). The treeless plain with its cover of brown 
or green grass has the thoroughly graded aspect and subdued 
slope of a region in late maturity ; and such it is in spite of its 
elevation and potential youth. So far as erosion is concerned 
it only waits for some stream to cut headward through the sur- 
rounding ridges to cause it to enter upon a new cycle at the 
very beginning of youth. The Yak Tash basin, southwest of 
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