254 Report on the Geological Structure of the Salt Range. [No. 3. 



recommendation in its favour, though from its liability to become 

 damp in moist weather, owing to its being impregnated with salt, 

 it rapidly crumbles, and hence cannot be recommended as a durable 

 building stone. If ever required for the purpose, the lighter colour- 

 ed portions of the rock should invariably be selected, as they are less 

 hygrometric than the darker variety. 



No minerals of importance have been observed in this rock. 



Although the most careful search was made, particularly in the 

 lighter-coloured beds where fossils are most likely to be found, not a 

 trace of an organic remain could be detected: when we bear in 

 mind the fact that only a few years ago, the old red sandstone of 

 Britain was regarded, " as the least fossiliferous rock in the geologic 

 scale," our want of success in obtaining fossils from its Punjab 

 representative, will not appear remarkable. 



The thickness of this formation varies a good deal throughout the 

 Range, and probably on an average is not less than 500 feet. The 

 upper surface of the beds frequently present ripple markings, indi- 

 cative of their having been deposited in shallow water. 



c. Greenish micaceous Sandstones and Shales with grey Dolomitic 



Sandstone. 



The red sandstone is generally succeeded by a series of greenish 

 micaceous thinly laminated sandstones, dark shales and coarse calca- 

 reous bands, which in the eastern part of the Eange are developed 

 into an extensive deposit of a very peculiar sandstone, varying from 

 nearly white to dark grey and weathering of a fawn colour. In many 

 localities it is brecciated, the fragments having become recemented 

 by a calcareous paste. A concretionary structure is by no means 

 uncommon, masses of the rock appearing to be sometimes made up 

 of nodules formed of concentric laminae like the coats of an onion. 

 Its lower beds are generally dark-coloured and parted by bands of 

 micaceous sandstones and shales ; brine springs not unfrequently issue 

 from these and their impregnation with magnesia is evinced by the 

 effervescence of sulphate of magnesia in fine acicular crystals, which 

 may be often observed under the ridges of rock. "When tolerably 

 well developed, the united thickness of this formation must be about 

 500 feet. 



