ancient Gypsum of the Alps. 69 



mineralogists, who regard the first (that of Val Canaria) as 

 primitive. 



3d. Steatite. This mixture is principally seen in the gyp- 

 sum of Cogne and in that of Sarran near Martigny. 



In the first, steatite forms small masses, most frequently 

 flat, and even small thin plates of a leek green colour, often 

 blackish, very translucent at the edges, and sometimes of a 

 fibrous texture ; these plates are disposed parallel to each 

 other, and to the plane of the gypsum bed, but they do not 

 form continuous planes, and do not give a laminated texture 

 to the rock ; they are too much scattered, and often of rare 

 occurrence. 



In the gypsum of Sarran, the steatite is in smaller plates, 

 of not so dark a green, but duller, and of a texture often 

 fibrous, approaching talc. They are disposed in the same 

 manner, generally closer together ; but there are also large 

 portions of gypsum which do not contain any at all. There 

 are among these plates some that bear a great resemblance 

 to the superficial thin plates of talc, ill defined at the edges, 

 mentioned above in the gypsum of Brigg. 



The gypsum of St. Leonard also affords some small plates 

 analogous to fibrous steatite, but ill determined. 



Lastly, I obtained a specimen of gypsum found at St, 

 Gervais, in Faucigny, near the hot springs, that contains a 

 great number of these plates of steatite, which is fibrous, 

 and often shining, without however possessing the demi- 

 metallic lustre of talc. I have not myself observed this gyp- 

 sum in place, but I have many times visited the country, 

 and different observations make me regard it as altogether 

 analogous to the gypsum of the Tarentaise, which is in the 

 neighbourhood. 



I shall here remark the affinity which the mixture of 

 steatite shows between the gypsum of Cogne, one of those 

 regarded as primitive, and many others (those of St. Leonard 

 and Martigny) considered as transition, not only according 

 to my own ideas, but according to those of other mineralo- 

 gists who admit the primitive gypsums of the Alps. 



