VREDBNBURG : SKETCH OF BAlOCHISTAN DESERT. 



Part III. 



PETROLOGY AND ECONOMIC GEOLOGY. 



Section i.— PETROLOGY. 



The journey which I performed through Baluchistan, although 

 not always favourable to geological observations on account of the 

 great distances travelled through, afforded nevertheless from this 

 very reason, an opportunity for collecting a most varied and exten- 

 sive collection of rocks. 



Two descriptions have been published of the specimens collected 

 in 1896, during the Afghcin-Baluch boundary commission, one by 

 Mr. Holland, and one by General McMahon (see ante, page 6). 

 Nevertheless the excellence of the material now at our disposal 

 represented, as it is, by a collection of several hundred specimens, 

 will still allow many important details to be added to these interest- 

 ing studies. Although a great deal of preparatory work has been 

 done, the study of such a vast amount of material has not advanced 

 far enough to justify the publication of any results. It is, therefore, 

 necessary to postpone, until some future occasion, the review of this 

 important subject. The following is a short resume of a few points 

 that have been noticed : — 



On page 40, a classification was* given, dividing some of the 

 igneous rocks into three groups according to 



Classification. . , . 



their geological age. 

 1 1 _ -Volcanic rocks of the " flysch " period, that is upper cretace- 

 ous and lower eocene. * 



2. Intrusions, principally acid and intermediate, probably upper 



eocene. 



3.— Basic intrusions cutting through those of group 2. 



To these must be added a fourth group, that of the recent 

 volcanic products which, if some of my observations be correct, 

 vvould require a further sub-division into 



4^ —Volcanic outbursts of Siwalik age, probably pliocene. 



4 ^_R CC ent and sub-recent eruptions. 

 ( no ) 



