- here water is the principal agent as it continually carries 

 away the products of erosion by the rivers. 



As regards Turkestan 1 ), MUSHKETOW maintains, contrary 

 to RICHTHOFEN, that this part is very similar to Central Asia 

 proper. It is without drainage to the sea and the eolian or 

 windborne deposits are the most important feature. The 

 rivers in the lowlands have no effluence, and can therefore 

 only be local agents in transportation. Moreover there is a 

 very close geological affinity, deposits from the Cretaceous and 

 Tertiary periods stretching, almost without interruption, from 

 Hanhai into Turkestan, not only through the ravine of Dsun- 

 garia but also more to the south. Hanhai and Turkestan 

 have been covered by the same Tertiary sea. 



MUSHKETOW therefore, for the present at any rate, rejects 

 RICHTHOFEN'S definition of Central Asia and designates as Asia- 

 Media the regions that are without drainage to the open sea 

 and amongst these Turkestan. (1. c. p. 11). 



Turkestan or the Turkestanian Basin, called by ROMA- 

 NOWSKI the Turanian Plain, is defined by MUSHKETOW as 

 follows: It stretches from the Mugodshar mountains .and 

 Usturt in the west to Tsungei Alatau, Thianshan and Pamir 

 in the east, from Kopetdagh and the Chorassan mountains 

 in the south, to Tarbagatai and Tjingistau in the north-east 

 and in the north to the watershed between this area and the 

 rivers running into the Irtish. (See the map appended to 

 this memoir). The mountain range Karatau divides the area 

 into two parts: the north-eastern Balchash Basin which is 

 not dealt with here except as regards the distribution of 

 plants, and the Aral Basin or the Turanian Basin proper. 



This latter is the subject of the present contribution, 

 but not to the full extent of the limits given above. In view 

 of the botanical investigations, it is advisable to fix the nor- 

 thern boundary in this memoir at about 46 N. Lat. This 

 line passes through the northern part of the Aral Sea and 

 thus cuts off the whole territory of the Kirghiz Steppe, The 



') Mushketow also discards East Turkestan as name of a geographical 

 area on the ground that it belongs to the Central region of Asia 

 (L. c. p. 13). 



