90 WYNNE : TRANS-INDUS EXTENSION OE THE PUNJAB SALT RANGE, 



Among" these, the groups of least certain age are more numerous 

 cis-Indus in the Eastern Salt Range than to the west, while beyond the 

 Indus they are reduced to the infra-carboniferous salt marl, purple 

 sandstone, gypseous and boulder, groups — the supra- Jurassic zone being 

 at least partly cretaceous. But of the four infra-carboniferous groups of 

 doubtful age two are common to the whole range, and known to be not 

 newer than silurian, l so far as at present ascertained. 



It may be assumed that in early palaeozoic times a considerable uni- 

 formity of conditions prevailed, giving rise to the formation, over an 

 extensive area, of a curiously unstratified soft earthy rock, largely im- 

 pregnated with iron and soluble salts, the latter frequently taking the 

 shape of chemically formed layers, probably within more or less cir- 

 cumscribed limits. 



Immediately succeeding this early period, more or less adjacent, old, 

 metamorphosed rocks were within the reach of denudation, of coast 

 or river action, and their debris carried here to be deposited in the 

 boulder group. Up to this point, there is no evidence in any part of 

 the range trans-Indus whether the palaeozoic deposits succeeding the salt- 

 bearing series were marine or fresh-water or estuarine, but after this they 

 became decidedly marine. 



In the eastern Salt Range marine deposits were certainly formed in 

 pre-carboniferous times ; here, in the west, they continued to accumulate 

 without interruption till the close of the triassic epoch. 



At this time disturbance, not proved with certainty, may have taken 

 place quite locally. The northern end of the Khasor range may then, 

 or shortly after the lowest Jurassic layers were deposited, have become 

 an area of suspended accumulation, if not one of actual denudation. 



In other places the Jurassic deposits continued to succeed the earlier 

 mesozoic ones, but during the period of the variegated series this may 

 have been formed in shallower waters, perhaps no longer entirely salt ; 



1 This is still unsettled, see Manual, p. 488, and Falseontologia Indica, Ser. XIII, 

 Vol. I, p. 6. 



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