56 M. CoRDiER on the Mountain of 



two-tenths. The gypsum and perfectly pure rock salt (No. 

 1) amount scarcely to a tenth. 



This mode of composition is without doubt worth atten- 

 tion, but the stratification is still more so ; thus all the ma- 

 terials of the mountain are disposed in parallel and vertical 

 beds, having a direction from E.N.E. to W.S.W, that is, 

 according to that of the crest stretching through the middle 

 of the circus. 



The mean thickness of each of these beds, thus placed on 

 their edges, may vary from one to six decimetres [about 4 to 

 24 inches] ; some are found of not more than a centimetre 

 [•Jj- inch], whilst others attain a thickness of seven or eight 

 meties, [about 23 to 26y feet]. Many saline strata of the 

 same sort are often in contact; they then can only be 

 distinguished by their grain and the contrast of their colours. 



This order of stratification is variously modified ; some- 

 times the thickness of a bed varies considerably in different 

 parts of its course, thus presenting exact parallelism; some- 

 times the planes are shifted in an opposite direction, pro- 

 ducing various inflexions in the lines of direction and dip. 

 These irregularities do not alter the general order. 



No order has been observed in the intercalation of the beds 

 of different kinds. They appear to alternate with each 

 other in no settled manner. All that may be said is, that 

 the clay is most abundant on the northern side, and that its 

 opposite side coi\tains scarcely any thing but muriate of soda. 

 The gypsum beds are not mixed with the rock salt ; they 

 occur interposed between the last clay beds on the north 

 side. 



Some of the steepest slopes of the mountain are cut by 

 fissures, so wide that they may be entered to the depth of 

 some metres. In these rugged places saline concretions are 

 found, sometimes tubercular, at others in mamillated plates ; 

 they produce a fine effect from the contrast their brilliant 

 white colour presents to the tints of the coloured bases over 

 which they are scattered. 



The perfectly pure and transparent rock salt beds are 

 almost all united on the E.S.E. side of the mountain ; they 



