GEOGRAPHICAL SUMMARY 
185 
though they are of a less imposing altitude. The valleys 
through which these several streams descend from the 
Pamirs to the lower regions exhibit features of a Transi- 
tional character. On the one hand, whilst they resemble 
the deeply trenched valleys on the outer borders of the 
plateau, with their large rivers in full flood all the year 
round ; on the other hand, they possess many features 
in common with the level plains of the central areas of 
depression. Although strictly speaking, according to Von 
Richthofen’s definition, the Ghez-daria and Yarkand-daria 
belong to the central area of depression, the districts 
through which they flow, and which their muddy streams 
to some extent help to mould and level up, exhibit the 
characteristics of a Peripheral zone. The drainage-basin 
of the Ghez-daria embraces four lakes, the two largest 
being Bulun-kul and Little Kara-kul. The Ghez-daria, as 
well as the Kara-su, an affluent of the Yarkand-daria, are 
fed principally by the snows and glaciers of Mus-tagh-ata ; 
so that in spring and summer their currents swell to streams 
of very respectable dimensions. On 28th April the Ghez- 
daria had a volume of 850 cubic feet in the second, and 
we had some difficulty in crossing it. Later on in the 
summer it cannot be forded at all. These two strong 
torrents have made an irresistible assault upon the 
Mus-tagh range ; both have cut their way through it. 
The Yarkand-daria is the chief contributory of the river 
Tarim ; indeed it furnishes the greater portion of the 
volume of its waters. 
Summarising in broad general terms, we may say that 
the Pamirs may be grouped in two sharply contrasted 
divisions — an eastern half, which is principally a plateau- 
land such as I have described, and a western half, consist- 
ing of a system of latitudinal mountain-chains disposed 
parallel to one another. There can be no doubt that at 
one period the entire region was strictly a plateau, and 
that it is being rapidly broken down by the agenc)/ of 
erosion. Indeed it is not more than a geneiation ago 
when the Pamirs were universally considered to be a 
plateau pure and simple. We know now, that they orm 
