60 SUB-HIMALAYAN ROCKS OF N. W. INDIA. [ClIAP. II. 



■crystalline rocks reach much lower down on the south side. There is 

 massive granitoid gneiss at Sulhetur. Here too the trappean schists, 

 below a well marked boimdary with granitic rocks, are themselves 

 felspathic, and even porphyritic. 



In connection with this portion of our area I must notice the well-known salt rocks of 

 Mundi. I approached these rocks with various expectations. Any 

 mention that had been made of them by geological observers in 

 India treated these salt rocks of Mundi as beyond question the geological equivalents of tho 

 salt rocks of the Punjab. It was indeed plain that the opinion was rather taken for granted 

 than founded upon evidence, yet the notion was sufficiently plausible to excite hopes of find- 

 ino- something new, and which might throw a light upon the general section. My curiosity 

 was increased by the fact, that the same authorities alluded to the Mundi salt as connected 

 with the red clay and sandstone deposits, which I have grouped in the Sub-Himalayan series, 

 although for many years it has been known, from Dr. Fleming's descriptions, that the salt 

 of the Punjab occurs in Palaeozoic (Devonian) rocks. The imaginary puzzle was of course 

 removed by a single inspection of the ground, but only to make way for a real one. I can state 

 that the salt occurs very close to, but well inside, the main boundary, among the limestone, 

 sandstone, and slates which I have supposed to be the same as the Krol rocks, and which are 

 here much complicated by trappean intrusion : but the natural history of the salt is still very 

 obscure. 



There are at present two localities where the salt is extracted ; one just below Drang, and 



the other fourteen miles to the north, at Guma. Both are at 



Position of the mines. ,. , „ , . , . ., _ , . . „ , 



the base of the steep and regular ridge, formed principally by 



the trappean rocks, along the boundary of this region of the Himalaya. In both cases the 



workings are placed right in the bed of the drainage gullies : whether or not this is a 



necessity entailed by the local distribution of the mineral I have no means of ascertaining ; 



but think it is not. These difficulties, natural or presumed, backed by improvidence and 



want of skill in the native managers, result in the almost total stoppage of the works during 



the rainy season, in the almost total destruction and obliteration each year of the open pits 



and short galleries by which the salt is extracted, thus involving the annual execution of 



t hese preliminary operations, which are sometimes very difficult. As may be expected from 



these facts, the opportunities for examining the allure of the mineral are very poor. The 



Mundi salt is commonly known in the neighbourhood as black 



salt ; it has a dark purplish hue, is quite opaque, and contains 



a large admixture of earthy impurities. An average sample gave twenty-five per cent, of 



earthy matter. The salt is pure chloride of sodium. It is only used by the poorer classes, 



who, as a rule, subject it to a purifying process by fire and water. Small nests of pure 



crystalline rock-salt are occasionally found, but so rarely as to be reserved for the special use 



of the Rajah and his household. 



Regarding the origin of this rock, we have to select one of these views, — contemporaneous 



deposition pseudomorphism, or. a totally subsequent introduction ; we will see that the 



