220 VREDENBURG: SKETCH OF BALUCHISTAN DESERT. 



east-south-east, away from the desert depression, giving one the 

 Probable existence of impression that the tangential force which folded 

 InTtt Sett deprel: the ranges, acted here from east to west. The 

 s,on# rocks of the mountainous region are probably 



forced over the desert depression along an overthrust plane. The 

 presence of Siwalik strata also dipping east, all along the western 

 foot of the hills, further strengthens this supposition. 



A few miles north of Nushki some hills of limestones and tuff 

 intervene between the main range with its fringe of Siwaliks to the 

 east, and the desert to the west. This is represented in section, 

 Fig. 3. To the west are black volcanic rocks, whose structure it is 

 difficult to make out; apparently resting upon these, with a gene- 

 ral eastern dip, but much crushed and contorted are some limestones 

 of various colours forming small hills. The limestones are pink and 

 flaggy or else green and shaly ; others are white, more massive, and 

 considerably brecciated. The limestone and the igneous rocks seem 

 to have re-acted upon one another giving rise to green alteration 

 products. The easternmost limestones are massive, brecciated, un- 

 accompanied by any volcanic rocks, but full of nummulites (d). 

 Judging by the dip alone, it would seem that the shales and sand- 

 stones of the principal range rest upon this nummulitic limestone, 

 but as it is very probable that an inverted fault runs all along the 

 foot of that principal range, it is difficult to tell in the absence of 

 fossil evidence what the real relations of the rock can be ; the 

 presence of a band of Siwaliks (e) between the nummulitic limestone 

 and the slates makes it all the more likely that a fault exists here. 



It has been mentioned that all along the western margin of the 

 great range where it borders upon the desert, slaty cleavage is highly 

 developed. The character of the rocks is so disguised by this 

 peculiarity that they might be taken for palaeozoic strata, and have 

 been several times described as such. In fact, this was my own opinion 

 when I first saw them. Afterwards, however, I observed that they 

 pass quite gradually into the shales and sandstones of the central 

 and eastern portions of the range. Nowhere can any rigid line of 

 ( 42 ) 



