244 VREDENBURG: SKETCH OF BALCCHISTAN DESERT. 



from north to south. The rocks constituting these mountains are 

 extremely interesting as there is reason to think that they form part 

 of one of the great volcanic centres of the flysch period. Unfor- 

 tunately my observations of this interesting district are very scanty; 

 I was never encamped amongst the mountains, but did nothing more 

 than touch them at a few points. The following notes contain an 

 account of the facts observed. 



I followed the road that leads from Chagai to "Balanosh ZiaVat," 

 Hilb north-west of a s P ot much resorted to by pilgrims. The rocks 

 Chagai. met w j tn are enumerated on the section, figure 12. 



The limestone (i) and possibly the highly metamorphosed rock (2) 

 and (3) are the only sedimentary rocks. In all the sections hitherto 

 described the volcanic products of the flysch period were in the shape 

 of strata, principally tuffs. But here we find a considerable develop- 

 ment of massive igneous rocks of basic character, evidently intru- 

 sive. There is great evidence of solfataric action which has given 

 rise to secondary minerals in great profusion, such as in the rock 

 JL?3- so rich in epidote as to be practically an epidote-rock. These 

 great intrusive masses consist of fine-grained rocks of volcanic 

 appearance and they may represent the deep-seated portions of some 

 of the great volcanic apparels of the flysch period. Most of the 

 volcanic products are submarine, but in some cases the ejected 

 materials must have accumulated to a sufficient height to form 

 islands as is shown by the waterworn pebbles observed in some of 

 the shallow-water deposits of the Ranikot age. The augite-bearing 

 gabbros and dolerites, in the present instance, are accompanied by 

 intrusions of a more acid composition particularly rich in micro- 

 graphic quartz. Their microscopic structure is porphyrinic or felsitic, 

 but coarser grained rocks will be mentioned from other localities 

 of the same group of hills, always presenting the same exceptional 

 composition of quartz and plagioclase felspar and with a typical 

 tendency to a graphic or micropegmatitic structure. The age of 

 these micropegmatitic quartz-diorites will be discussed further on 

 (page 63). 



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