RECONNAISSANCE IN CENTRAL TURKESTAN. 185 
The simplest case is where a valley contains two moraines, one below the 
other, as in the valley of Kashga Su, a tributary of the Ulakhol at the southwest 
end of Issik Kul. Here, at an elevation of 7,400 feet, the lowest altitude at which 
any evidence of glacial action was seen, the lower portions of an old moraine are 
buried in valley gravels. The moraine itself consists of bowlders and rock waste of 
various sizes and kinds, deposited together in the usual glacial fashion. Its higher 
surface is smooth and rounded to such an extent that the topography peculiar 
to young moraines is almost obliterated, and the lower portions of the moraine 
show irregular hillocks and short ridges projecting out of a smooth valley floor of 
gravel in such a way that a removal of the latter would show the ordinary- kettles 
of a typical morainic topography. Farther up the valley there is another moraine, 
entirely separated from the first. It has a younger, fresher appearance, and is not 
at all drowned in gravel ; hence it must have been formed at a considerably later 
date than the other; but so far as the evidence of this valley is concerned the 
younger moraine might be merely a stage of retreat of the older one. 
In other cases the relation is not so simple. The younger moraine lies, as it 
were, in the anus of the older, and the two appear to have been formed at widely 
diiferent times, separated by a long period of aqueous erosion during which the ice 
retreated farther up into the mountains than the position of the younger moraines. 
One among many examples of this is found in the Tuluk Valley, north of Son Kul. 
Near the head of this valley and on its north side are two tributary- valleys, from 
each of which projects a large body of morainic material which seems to be of two 
ages. The older moraine of the western or larger tributary- takes the form of a rounded 
spur with its base at a height of about 10,000 feet. The spur has a long, grassy 
slope, fairly steep but thoroughly graded, and showing few bowlders. Its morainal 
character is more distinct on the top at a height of about 10,500 feet, by reason of 
ridges, imperfect kettle-holes, and other characteristic forms, and also b)' reason of 
more numerous bowlders. The topography is not fresh, however; the kettles are 
all drained, the slopes are gentle, there is a well-developed though circuitous 
drainage system, and the occasional bowlders are well rounded and deca}ed. The 
stream coming from the mountains has cut through the moraine an open flat-floored 
valley with graded sides. If this open valley is followed up, it comes to a sudden 
end at an elevation of about 10,000 feet, and above this level it is filled with a 
moraine that appears to be of much later date. The steep front of the latter has a 
slope of 30° instead of about 15°, as is the case in the older companion; there are 
deep, steep-sided kettles, some of them containing pools of water; drainage is but 
little developed, and the bowlders are mostly subangular. The stream here flows in 
a narrow V-shaped valley, the sides of which have an average slope of 35°. Yet 
the same stream, working just below in the other moraine, in what .seems to be 
the same kind of material, has carved out a valley many times as large, with sides 
that slope at an angle of only 22°. The inner, smaller moraine shows all the signs 
of youth ; the outer and larger all those of age. The two must ha\e been fonned 
at times so far separated that one moraine has had time to be maturely eroded and 
degraded while the other still remains young. As to what climatic conditions 
intervened between those times, and as to whether the two moraines represent two 
