Chap. IX] 



DESERTS 



623 



occasionally extend for distances of six or seven miles. Localities of the 

 same kind characterize the central Gobi, whilst in its northern and southern 

 parts mountains frequently occur, partly grouped like an archipelago, 

 partly extending in chains. The mountains are only slightly raised above 

 the flat tracts of land at their feet and are covered with rocks, which 

 one encounters at nearly every step. Frequently dry river-beds, full of 

 water only during the rainy season, also occur. Springs are situated at the 

 higher elevations. In the Gobi, as in the adjoining region, permanent 

 water-courses are absolutely wanting. During the rainy season temporary 





M 1 ^- 



-"■W-v C-» 



mam 







fwa.2. -~ 



"■ 1% 



Fig. 357. Desert of Gobi, near Lake Lob-Nor. After Przhevalsky. 



lakes and rivers form, which dry up during the hot season. There are no 

 lakes with a permanent supply of water. 



' The soil of the true Gobi consists of coarse-grained red sand, sometimes 

 intermixed with various kinds of gravel. One seldom finds tracts com- 

 pletely devoid of vegetation ; on the other hand the grass in many places is 

 barely one foot high, so that it only scantily covers the red ground. Along 

 the depressions of the valleys, where the water flows during the rainy 

 season and collects in ponds and lakes, the grass is ranker and attains 

 a height of three feet. . . . 



' Throughout the Gobi there is no forest, and only rarely a single tree at 

 the foot of a mountain or on the bank of a dried river-bed stands as an 



