2S WYNNE: TRANS-INDUS SALT REGION, KOHAT DISTRICT. 



Thickness. — Using these bedding planes and their inclination by 

 which to calculate the stratigraphical thickness, the maximum thickness of 

 the salt-rock in one part of the Bahadur Khel exposure is thus found to 

 amount to no less than 1,230 feet in round numbers. So that even 

 making a large deduction for any slight alterations in the angles of in- 

 clination to say the salt has here a visible thickness of one thousand feet 

 is apparently considerably within the mark, for the section giving this 

 thickness ends both ways in salt. Even on the spot it is difficult to 

 realise this great thickness as being true. Yet almost every bed from one 

 side of the valley to the other might be counted, and their steep northerly 

 dip is palpable. In mentioning the detailed features of this locality, 

 some facts will be noticed which might strengthen the suspicion that 

 an exaggerated appearance of their original thickness obtains, but this 

 could only be reduced upon supposition, while, however produced, the 

 measured thickness is a fact. Both east and west of this measured thick- 

 ness, the salt has an anticlinal structure reducing its bulk, but here it is 

 also much less exposed. In other parts of the district large thicknesses 

 of one, two, and three hundred feet of salt beds without any alternations 

 of unworkable salt are exposed, but in no case can it be said that the 

 bottom of the deposit or deposits is seen. 



Manner of exposure, — The salt is here associated with gypsum, as 

 is commonly the case, the gypsum also, as in perhaps a large majority 

 of instances where both are present, overlying the salt. This gypsum 

 being less soluble by rain water occupies an enormously greater superficial 

 area than the salt; and the association of the two perishable rock 

 minerals with masses of soft gypseous and other clays within the anti- 

 clinal curves of limestone in situations subjected once to great lateral 

 pressure, and subsequently, from their superior elevation, favouring the 

 action of the denuding agencies (to which they are still exposed), is 

 doubtless the reason why the rocks in the interior of the nummulitic 

 ellipsoids present such a broken, confused, and concealed state of irregu- 

 larity. Amidst obscure masses of gypsum covering and undulating over 



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