254 VREDENBURG: SKETCH OF BALUCHISTAN DESERT. 



Neighbourhood of Mukak, 



Mukak, a spring to the east-north-east of Mirjawa, lies amongst 

 the continuation of the above described ranges. The ranges have 

 now gained considerably in altitude, and the degree of disturbance has 

 also greatly increased. Cleavage has distinctly set in. The greater 

 height of the ranges favours the production of rain ; hence the rocks 

 in the longitudinal valleys between the principal ridges are once 

 more concealed by accumulations of coarse alluvium. 



The section (Fig. 14) shows the principal points to be noticed 

 in the neighbourhood of Mukak. South-west of the point (a) there 

 are a few hillocks forming parallel ranges, all of them consisting 

 of the ash-beds, shales, etc., of the flysch series. Mukak karez is 

 in a shallow syncline ; then we find next an anticline. At (b) the 

 amount of dip is about io° ; cleavage is distinctly seen. Further 

 on comes a t( dasht " plain with low ranges ; at the point (c) the 

 dip is about 40 E. of N. at 40 , the rocks still belonging to the same 

 varieties. The cleavage is still well pronounced, the cleavage planes 

 nearly vertical. The tall range at {d) consists of the same columnar 

 basic rocks already mentioned at Tozgi and elsewhere (page 73). 

 Here the junction of the columnar rock with the underlying sedi- 

 ments is exposed uninterruptedly for considerable distances. The 

 igneous rock rests upon flaggy limestones and shales of a kind 

 very common amongst the flysch series. In immediate contact 

 with the igneous rock there is a band of a greenish colour and of a 

 texture resembling that of porcellanite, probably the effect of 

 contact metamorphism ; it is not ; however, more than one inch in 

 thickness, showing that whether the igneous rock be intrusive or 

 truly interbedded, its metamorphic action has been very slight. 

 Nowhere could the igneous rock be seen cutting across the bedding ; 

 the junction is absolutely sharp, the igneous rock remaining very 

 coarse-grained up to the actual junction. 



Beyond the point (d) comes another plain of " dasht " ; then more 

 ranges appear ; at (e) there is a cliff formed by a thick band of 

 ( 76 ) 



