2] 2 VREDSNBURG : SKETCH OF BALUCHISTAN DESERT. 



low angle. It consists of finely comminuted debris together with 

 volcanic pebbles which vary in size from the 

 smallest ash up to fragments of about one 

 decimetre at most. In some exceptional instances, where ash-beds 

 are exposed nearer the central cone, some much larger boulders 

 were observed. These ash-beds are very similar to those of the Koh- 

 i-Sultdn. They have been deeply cut into by streams forming gorges 

 bordered by cliffs. These valleys are, however, very narrow ; every- 

 where else the surface of the ash-beds presents a gently undulating 

 surface, denudation having acted only locally. 



In all the portions of the volcano which I have visited, these ash- 

 beds are the oldest formation. The explosive eruptions that produced 

 them were succeeded by the outpouring of great flows of lava. 

 These flows appear to be of great thickness ; at Timi they terminate 

 in a northward direction by a rather steep escarp- 



Lava-flows. 



ment, rising above the imperceptibly sloping 

 surface of the ash-beds. From this point up to the base of the 

 central peaks there rises a broad shallow cone entirely composed of 

 lava, whose gentle slope is only locally interrupted by scarps of similar 

 appearance to the terminal scarp at Timi, and indicating the end of 

 a lava-flow. This gigantic slope must be composed of many succes- 

 sive lava-flows in superposition or in juxtaposition. This would 

 probably be ascertained by examining some of the ravines which the 

 rivers have cut through their mass. So far as mineralogical characters 

 go there does not seem to be much to distinguish the lavas from one 

 another, all the differences which I have observed being variations of 

 texture such as may be frequently observed, even in different portions 

 of a single lava-flow. The surface of these enormous fields of 

 lava has become weathered into irregularly-sized boulders thickly 

 carpeted with aromatic shrubs. 



The double central cone itself consists entirely of lava which has 

 solidified at high angles. The south-eastern peak appears newer 

 than the nOith-western one; its shape is that of the latest flow of 

 lava which has solidified half-way down its slopes, while the lavas 



( 94 ) 



