ancient Gypsum of the Alps. 85 



as I have shewn, since mica exists also in the same manner 

 in admitted transition g;ypsums, and as this substance occurs 

 in many other transition rocks. 



Its primitive origin is then any thing but proved. I may 

 even go further, for I strongly suspect that this gypsum is of 

 the same epoch, and occurs in the same manner as the other 

 gypsums of the Valais that I have before described ; it 

 would indeed be very extraordinary that the Valais, con^ 

 taining at least three portions of well recognised transitioa 

 gypsum, should also present a primitive one, which is 

 in other respects analogous to the former : and if such were 

 the fact, we should have reason to be astonished at meeting 

 but with this single example in the Alps, when nature 

 exhibits herself so much in the great scale in that chain, and 

 the same rocks are distributed over such a vast extent of 

 country. I shall moreover add, that the Alps are the only 

 chain in which primitive gypsum has been supposed to be 

 recognized ; it will then be the only primitive rock of which 

 an analogous one has not been found in some other chains. 



It remains for me to sum up the conclusions to which the 

 facts I have produced have led me, 



Summari/. 



1. It does not yet appear proved that there are in the Alps 

 or elsewhere, beds or masses of gypsum distinctly contained 

 in primitive rocks, and possessing characters of contempo- 

 raneous origin with them. (I have demonstrated above that 

 the gypsum quoted as primitive in the valley of Canaria, and 

 in that of Cogne, is of later origin.) 



2. Many gypsums of the Alps form beds in a decided 

 transition series. 



The beds with which this gypsum is associated are lime- 

 stone and argillaceous schist, which here represent the grey- 

 wacke or anthracite formation. (The gypsum of Cogne, of 

 Brigg, and of Bex, belongs to this class. * ) 



* Of these examples that of Bex, at least, is secondary. (Trans.) 



