70 M. Brochant on ike 



4tli. Anhydrous sulphate of lime. This substance has 

 been equally found in many gypsums of the Alps, and in 

 gypsums of Germany, which belong to very ancient rocks, 

 but which are recognised as secondary. It exists in the 

 Alps in the midst of gypsum masses and also in the rocks 

 near them. Defined crystals and crystalline masses with 

 large laminae more particularly occupy the clefts in the 

 neighbouring rocks; but in the midst of the gypsum, the 

 anhydrous sulphate of lime more commonly forms bunches, 

 and more or less considerable masses of a confused laminated 

 structure, with a crystalline fracture, sometimes in concentric 

 layers, of a whitish grey colour approaching violet. 



I have thus observed it at the glacier of Gebrulaz, in the 

 gypsum of Pesey, in the Tarentaise, at AUevard, &c. ; I do 

 not however pretend to a£5rm that this substance never 

 forms beds in the gypsum ; it certainly appears to occur 

 thus at Bex. 



I am not as yet acquainted with any description of the 

 position of the anhydrous sulphate of lime of Vulpino. If, 

 as I am led to presume, it is analogous, the masses that it 

 forms in the gypsum must be very considerable. 



5th. Muriate of Soda and saline springs. The presence 

 of muriate of soda is recognised in many of the gypsums of 

 the Alps, that I have observed. The gypsum contains rock 

 salt in the valley of the Arbonne, near St. Maurice in the 

 Tarentaise ; this salt is often visible in powder on the sur- 

 face; it also has been attempted, and not without success, 

 to obtain muriate of soda from it by solution. 



The saline spring of Moutiers rises out of limestone, but 

 at the foot of a considerable mass of gypsum ; other saline 

 springs of the Alps are in the gypsum itself, which often 

 contains a little rock salt. The gypsum of Bex appears to 

 be decidedly iuclosed in transition rocks ;* but on the other 

 hand, many saline springs and deposits of rock salt worked 

 ip Germany occur in masses of gypsum mixed with clay, or, 

 as has with truth been said, in masses of gypseous muriatife- 



* Jt will be hFveaftcr »litivii ihal they aic secondary. (Trans.) 



