206 Report on the Geology t Zoology, SfC. [No. 135.. 



Resting upon the red sandstone we have the red marl in which the 

 rock salt and gypsum occur imbedded. Its colour, as in other quarters 

 mentioned, varies exceedingly, being red, white, blue, green, &c. The 

 rock salt occurs in vast beds of several hundred feet in thickness, 

 exposed and close to the edge of the river, so that when it rises, owing 

 to the hot season causing the melting of the snow in the mountainous 

 regions to the N. and N. N. W., it uniformly washes away a part of 

 the salt ; its color is generally red, approaching to rose red, but some- 

 times white ; structure lamellated, but very compact. The gypsum 

 associated with it is either of a rose red, or greyish white colour, and 

 of a granular structure. Like the rock salt, it occurs forming moun- 

 tains of considerable height ; in some places we find it studded with 

 crystals of rock crystal, the colour varying in general with the rock ; 

 the most beautiful varieties are the rose red, but they also occur white, 

 grey, brick red, black, &c, varying from transparent on the edges to 

 semitransparent, translucent and opaque j in form generally the six- 

 sided prism terminated by the double six-sided pyramid, but with 

 numerous modifications of the terminal planes, and sometimes the lateral 

 planes are wanting altogether, when we have formed the double six- 

 sided pyramid. In other crystals one of the lateral planes will be large at 

 the expense of all the other five, which are only represented in miniature, 

 but the forms are much too varied to attempt to notice them all. In 

 size they vary from that of millet seed to two or three inches. The 

 resplendent appearance presented by the gypsum when the sun is shin- 

 ing, produced by these imbedded crystals, is very striking. The occur- 

 rence of rock crystal in this locality is both very extraordinary and ex- 

 ceedingly interesting, and this is the only one that we are aware of in 

 which silica in a pure state is thus associated with sulphate of lime. In 

 the carbonate of lime or limestone, it is met with, but even in this loca- 

 lity it is rare. The crystals are of contemporaneous formation with the 

 gypsum, and probably have been formed by segregation of silica from 

 that rock. In the rock salt, though much more rarely, crystals are 

 also found imbedded. 



Associated with the red marl there is a white sandstone in which coal 

 along with mineral sulphur occurs. To examine its value and adapta- 

 tion to economical purposes, particularly steam vessels, was one of 

 the principal objects of my journey to this place. The late lamented 

 travellers, Burnes and Wood, had each reported, I believe, to Govern- 



