'PHYSICAL FEATURES, 185 



Chapter II.-PHYSICAL FEATURES. 



Section i.— General Characters. 



The country examined is included within the parallels 28°3o'' 

 and 3o°N.. and the meridians 6o°3o' and 66°E. 



Geographical situation. r ... . 



It may be roughly divided into two regions,- each 

 possessing a different type of structure. The northern part is mostly 

 a great desert plain with a few groups of hills irregularly scattered 

 about it, and extends northwards as far as the Helmand river and 

 even beyond. To the south-east, south and south-west, this com- 

 paratively low-lying area is bounded by ranges of mountains in 

 parallel or rather concentric ridges forming roughly an arc of a circle. 

 To the extreme east and extreme west of the region visited, at 

 Nushki and at Ron-i-Malik-Si^h, where the ranges strike respect- 

 ively north-east and north-west, the mountains form very close-set 

 parallel ridges. But in the interval between these two extreme 

 points, the inner ranges, that is those bordering on the great desert, 

 become gradually separated from one another by broad plains, 

 mostly desert areas strewn with black pebbles, when not invaded 

 already by the sand dunes. 



Throughout the region characterized by parallel ranges, the rocks 

 L<< ' are nearly everywhere highly folded, with a 



Two types of structure. J J ° J ' 



considerable development of slaty cleavage. 

 The hills which rise in isolated groups from the midst of the great 

 desert plain, on the other hand, exhibit only moderate flexures without 

 any predominating direction of strike, or the rocks constituting 

 them may even be quite horizontal. The broad plains above men- 

 tioned as occurring between the parallel ranges partake of the nature 

 of the great desert depression ; both must be regarded as regions of 

 minimum disturbance, and they are moreover, in many cases, real 

 areas of subsidence. This is well shown by the structure of the 

 mountains in their neighbourhood ; they exhibit in a marked degree 



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