70 ASIA 



summer and winter is as bad as the true plantless 

 desert. This is also the case with the Ordos plateau, 

 which lies inside the loop of the Hwang-ho. 



The alternate availability of summer pastures in the 

 mountains and winter pastures in the lowlands has 

 determined the nomadism of the Mongolians, along 

 the whole margin of the plateau. This nomadism is 

 mitigated by the fact of a double chain of oases, where 

 permanent cultivation is possible, an inner line of swamps, 

 and the line of loess terraces, which are often transformed 

 into fertile orchards and corn-fields. 



On the two sides of the desert the character of the 

 natural and the cultivated vegetation is different: on the 

 northern side it is frankly northern, on the south it is 

 mediterranean. Thus the lower valleys, south of the 

 Tarim, display rich orchards of apricots, mulberries, 

 melons, grapes, pumpkins, walnuts ; and fields of maize, 

 similar to those of Fergana and the upper Amu. This 

 is the more readily explained by the fact that the present 

 desert is the bed of a former inland sea whose last and 

 feeble vestiges are found in such erratic and vanishing 

 sheets of water as the Lob-nor, the Ebi-nor, the Bag- 

 rach-kul, and others. Long after the disappearance of 

 the sea, a more generous climate prevailed over the 

 broad plains strewn with large lakes. Water was more 

 abundant than it is now, and large rivers wound far into 

 the plain,while agriculture supported comparatively dense 

 populations : important cities also were engaged in active 

 trades. The gradual drying up continuing, forced the 

 cities nearer and nearer to the mountains, burying the 

 old ones in the sand, The lofty chains increasingly 

 grudged their scanty waters to the plains, and the popu- 

 lations had to depart with their herds, to follow the 

 broad belts of steppes between the snows and the deserts, 



