140 



THE ULTIMATE SOURCE 



salt was found in a bore hole at a depth of 1,293 feet. At 

 Cordona, in Spain, a mountain of rock salt, the depth of 

 whose base is unknown, rises to upwards of 500 feet. The 

 Trans-Indus salt hills reach an elevation of 200 feet. The 

 great salt lake area of lake Utah, equal to about 2,000 square 

 miles, is situated at an elevation of about 4,000 feet, in the 

 Rocky mountain district. The rock salt at Hallein, near 

 Salzburg, is 3,300 feet above the sea level ; and that at 

 Arbonne, in Savoy, is 4,000 feet higher, being perched in 

 the region of perpetual snow at an elevation of 7,200 feet 

 above the sea level. 



The physical characteristics of rock salt, and the formation 

 of its beds, will claim our attention before we can satisfac- 

 torily attack the problem of its origin ; but as these considera- 

 tions lead up directly to the question of origin, it is as well 

 to open that question here. 



A good deal of obscurity shrouds the origin of rock salt 

 deposits, and geologists are not all agreed as to their mode of 

 formation. Dr. Fleming, who surveyed the geology of the 

 Indian salt range in 1848-53, attributed the salt formation to 

 eruptive agencies, as the result of his own observations. Sir 

 R. Murchison says that other distinguished geologists have 

 arrived independently at the same conclusion. Dr. Mac- 

 culloch remarks of all rock salt formations, " The purity and 

 solidity of the masses of rock salt, their bulk, their insulated 

 and peculiar positions, with many other facts on which I need 

 not now enter, prove that they could not have been derived 

 from the ocean in the manner thus supposed, nor probably in 

 any manner. They are special and original deposits, in 

 whatever way produced.' ' On the other hand the majority, 

 perhaps, of writers upon this subject, look upon rock salt as 

 being a sedimentary rock, of aqueous origin, and formed from 

 the sea. It is nevertheless admitted that the aqueous theory 

 is open to several and serious objections, which require to be 



