SECTION I. TRANSCASPIA AND ITS 

 NATURAL CONDITIONS 



CHAPTER I 



Situation and Boundaries of the Region examined. 



THE great tract of lowlands, a southern extension of the 

 West-Siberian plain, stretching from the Caspian Sea to 

 the country round Lake Balchash, and having as its southern 

 boundary the mountains of northern Persia, the Thianshan 

 and Ala-tau and which is in open communication with the 

 south of Russia, to the north-west, through the plains north 

 of the Caspian Sea, cannot strictly be designated as belonging 

 to those portions of the continent which are without drainage 

 to the sea. The Duab or country with two streams tra- 

 versed by the two great rivers Amu and Syr, both flowing 

 into the Aral Sea, is of the type designated by RICHTHOFEN 

 as a peripheral region, that is a region whose waters are car- 

 ried by rivers to the sea, or to remnants of sea which are 

 now lakes. RICHTHOFEN'S Central Asia, on the contrary, in- 

 cludes the areas in the interior of Asia which are devoid of 

 any drainage to the sea. Here the wind is the principal 

 geological agent, and all the products of chemical or mech- 

 anical disintegration remain in the country ; they are only 

 moved from one place to another, filling up the hollows 

 and thus imparting a monotonous aspect to the country. 

 While, as RICHTHOFEN remarks, the movement in Central 

 Asia is centripetal, it is centrifugal in the peripheral regions, 



