Dr. Traill on the Salt Mines of Car dona, 405 



The great body of the salt forms a rugged precipice, which is 

 reckoned between 400 and 500 feet in height at the upper extremity 

 of the valley, and is covered by a thick bed of the clay above 

 mentioned. 



The precipitous form is partly owing to the manner In which the 

 mine has been wroilght for a series of ages. There is no excavation ; 

 ^ut the salt has been procured by working down perpendicularly as 

 in an open quarry. The lowest part of the present works has a 

 solid floor of pure salt which is not above the level of the bottom 

 of the valley where no salt is found ; but the real depth of the bed 

 of salt has never yet been ascertained. The upper surface of the 

 salt is not level ; but appears irregularly elevated, according to the 

 general outline of the hill in which it occurs. 



The salt has been usually represented as forming an entire moun- 

 tain : but though it here appears supplying the place of common 

 rock, yet from its being confined to this valley, and not attaining so 

 high a level as the surrounding hills, it would seem more correct to 

 consider it as a mass or bed of salt filling up a valley, than as con- 

 stituting a mountain, which according to some authors* is a league 

 in circumference. These dimensions could only be obtained by 

 considering the neighbouring heights as formed of this mineral j a 

 supposition not countenanced by my personal observation, nor by 

 the best information which I could collect on the spot. 



The surfaces of the salt precipice which have been long exposed 

 to the weather are not smooth, but cut into innumerable shallow 

 channels, running in a tortuous manner, and divided from each other 

 by thin edges, often so sharp as to cut the hands like broken glass. 



* Iiitroduccion a la Illsloiia Natural y a la Geografia Fisica de Espana, por Don 

 Guillermo Bowles. — Madrid, 1773. — Dillon, who translates him. Laborde, Itineraire 

 descriptif, &c. 



