1853.] Report on the Geological Structure of the Salt Range. 335 



of Foraminiferse, especially of nummulites which are most apparent in 

 the weathered surface of the rock, a freshly fractured surface often 

 presenting no trace of them. 



It is very hard but brittle, and presents a splintery conchoidal 

 fracture. The rock is invariably traversed by deep fissures and 

 cracks indicative of its having suffered severely from the commotions 

 to which the Salt Eange has been subjected. 



It is a very fine limestone dissolving rapidly in muriatic acid, and 

 with the separation of a small quantity of flocculent silica. 



The nummulite limestone formation west of Pind Dadun Khan 

 forms generally the top of the escarpment of the range, appearing 

 between that place and Kuttha and in the Chichalee Eange, in pre- 

 cipitous cliffs several hundred feet high, which weather of a white 

 colour and in the distance have a strong resemblance to chalk. 



Owing to the rapid disintegration of the shales in the cliffs, the 

 limestone becomes undermined, and huge masses of the rock thus 

 become detached, and strew with their debris the steep sides of the 

 hills. To the north of the escarpment of the range in its central 

 part, the nummulite limestone in a great degree conceals the inferior 

 rocks, and is generally distributed over the ridges, table-lands and 

 valleys which intervene between its north and south sides. Its 

 strata are, however, very much broken up, and in all the deep ravines 

 its relation to the inferior rocks may be observed. 



The thickness of the formation varies much, but when well deve- 

 loped, it cannot be less than a thousand feet ; in many places it is 

 much more. 



In this formation the limestone as a source of lime is very valuable, 

 being more generally burned, than any other limestone, in the Salt 

 Eange. It is never quarried by the natives who have only to collect 

 the boulders of it which are strewed in great abundance all along 

 the foot of the hills. 



From its brittle splintery character, and the difficulty of obtaining 

 blocks of it of any size, it is not adapted for a building stone. 



The minerals we shall notice as occurring in this formation are 

 the alum shales as a source of alum, and thin enclosed beds of lig- 

 nite, petroleum and mineral sulphur. 



Alum shales are extensively mined at Kalibagh, and at Kathee in 



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