78 WYNNE: GEOLOGY OF THE SALT KANGE IN THE PUNJAB. 



The banded structure of the salt beds is chiefly caused by layers 

 of different colour, the bands being most solid, 

 looking- or of darkest colour about the middle and 

 softened into a paler tint on the edge ; sometimes there are alternating 

 layers of a red earthy nature from which Epsom salt effloresces. The strata 

 have a regularity intermediate between that ordinarily observable in flag- 

 stone and sandstone, the bands or layers having in some places for consi- 

 derable distances vertical to their planes a general thickness of 6 to 8 inches 

 varying to 2 feet, while for several yards across the strike in some of the 

 larger beds no lamination at all is to be seen. There are also numerous 

 irregularities of the bedding showing much lenticular arrangement of 

 deposition. In one place an earthy film was observed crossing a thick bed 

 in a zig-zag manner as if a crack had been filled up. No sign of current 

 (ripple) mark or well-developed oblique lamination could be found. Layers 

 of the salt thinning out, convex above and below, were frequently 

 seen. 



A contorted band of salt between two layers of hallar similarly 



curved was observed in the 10-feet 

 marl bed ( fig. 5 ), the appear- 

 ance being precisely similar to 

 that produced by disturbance in 

 ordinary stratified rocks, though 

 the arch was only about 3 feet 

 across. One of the uppermost 

 layers of the salt in the Khewra 

 gorge has a mechanical brecciated 

 soJx. "b KcJiar- "^ structure, and encloses fragments 



of marl, gypsum, and of rock-salt. 



Fig. 5.— CoQtortion in beds within the Mayo salt mines. 



The whole of the group of salt beds at this place is shown to be 

 curved by the different angles of dip observable, but none of the 

 complicated little foldings so common in the adjacent gypsum and 



( 78 ) 



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