IRAN . 45 



of Kerman and Khorassan, whose limestone slopes are 

 generally as porous and barren as those of Zagros. 



Very different is the appearance of the desolate plains 

 which lie at a lower level east of Teheran and north-east 

 of the Kerman chain. This portion of Persia is much 

 poorer in water and more extreme in climate than the 

 plateau of Shiraz-Isfahan ; in fact, it corresponds to 

 the arid alfa plateaus of north-west Africa. A per- 

 sistent and strong dry wind from the north keeps down 

 all tree-growth and is the specific feature of the climate. 

 Vast expanses of sand-wastes and salt-tracts are well- 

 nigh devoid of vegetation or peopled by straggling 

 colonies of salt-bushes. Other areas support a loose 

 brush of tamarixes. Broad stretches of rubble, especially 

 in the eastern part, grow only solitary bushes, thorny, 

 leafless, and stunted, and tufts of stiff, wiry grass. 



Life is confined to the immediate margins of the rivers 

 which diverge from the Hindu Kush, or, again, to the 

 valleys of that belt of low hills which separates Kuhi- 

 stan from Afghanistan. In the middle of the wide 

 expanse of barren gravel lies the oasis known as Seistan, 

 a very rich country due to the convergence of the Hindu 

 Kush rivers towards the lowest point of the relief at the 

 foot of the central chain of hills. Here are exhibited 

 the characteristics of the northern vegetations, and agri- 

 culture is of a northern type ; cereals and fruit-trees 

 are profusely grown under shelter. Seistan was known 

 in the past as one of the granaries of central Asia, but 

 with increasing dryness, its limits have contracted con- 

 siderably. Swampy tracts between the affluent rivers 

 are covered with jungles of tamarixes, similar to those 

 of the Tarim desert. 



Farther south, the sub-tropical character is asserted 

 clearly in the oases, which like those of Africa and 



