I96 VREDENBURG: SKETCH OF BALtJCHISTAN DESERT. 



The volcanic material occurs mixed in all proportions with the ordi- 

 nary sedimentary particles, here forming almost the totality of the 

 rock, while at other times we find only a few cinders scattered 

 through a limestone full of fossils. 



All these volcanic rocks alternating with nothing but marine 

 sediments are consequently of submarine origin, and real lava-flows 

 are seldom met with. Some great sheets of columnar diorite 

 abundant in the vicinity of Ladis and at Tozgi are probably of the 

 nature of intrusive sills, though belonging perhaps to the same 

 series of eruptive products. 



As in the case of the flysch of Europe, the age of these volcanic 

 rocks extends from cretaceous to eocene. As might be expected in 

 the case of strata of this nature, their distribution in space as well as 

 in time is irregular, which will be seen in the chapter devoted to 

 detailed descriptions. But although no definite laws preside over 

 their distribution in space throughout the region examined, yet it 

 would seem that as far as the geological horizons are concerned, 

 they appear to occur more sparingly as we rise through the eocene. 

 In many cases the absence of fossils does not allow of any determin- 

 ation of age, but great thicknesses of slates interbedded with 

 limestone bands full of nummulites which probably correspond in 

 age with the " Ranikot " of Sind are almost free from volcanic 

 material. At K6h-i-Malik-Siah where an extensive series of shales 

 ia shown conclusively by fossil evidence to belong to that age, there 

 is little, if any, volcanic material. On the other hand at Saindak, strata 

 with a typical (i Khirthar" fauna rising up to the base of the " Nan" 

 stage immediately overlie a thick volcanic conglomerate the very 

 coarseness of which would tend to show, however, that it must be 

 of local occurrence. In several instances strata of the " Cardita 

 beaumonU 1i age are interbedded with sediments containing a fair 

 proportion of volcanic material. It is well known that in the 

 neighbourhood of Quetta an important volcanic band separates the 

 hippuritic limestone from the nummulitic strata. Lastly, in the 

 hill called " K6h»i-Humai," I observed a thick bed of hippuritic 

 limestone resting upon an extensive series of the most typical tuffs. 

 ( 18 ) 



