Jtg£ GEOLOGICAL OBSERVATIONS IN FRANC|;. 



|hat have fallen from the mountain are many remarkajj^j 

 J(arg^ comua ammonis. I 



JM^et. Mount Buet may be ascended not only from the valley 



^fferentroadiof gj^t, taken by its first visitors, Messrs. Deluc ; or that 

 of Berard, the way chosen by Mr. Bounit, and described 

 by Mr. Saussure ; but by crossing mount Breven from the 

 priory of Chan^ouni, or from Servoz, by going up the val- 

 ValdofVilly. l^y of ViUy* This valley is watered by a rivulet, which 

 JEbrnas the precise boundary between the primary and secon- 

 dary rocks. Another observation to be uaade in this road Ib^ 

 that the mountain above Servoz, which terminates the chain 

 of Aiguilles rouges to the south-west is in great part formed 

 ^f a primitive micaceous gritstone ; there being only the 

 suipmit called Aiguilette, that is composed of a foliated 

 rock like that of mount Breven. In like manner at the 

 north-east of the chain the pass of Charlenton is formed of 

 a primitive gritstone, remarkable for its well defined small 

 quartz crystals; and is the intermediate point between the 

 primary rocks of the chain of Aiguilles rouges and the tran- 

 €rit or pud- sition limestone of the summit of Buet. This is another in- 

 clingstone ge- stance in support of Mr. Saussure*s remark, that bed? §€ 

 the^pninary^" grit or puddingstone are almost always , foun^ betwefta the 

 and secondary last secondary and first primary strata. 



ffi '^^^ valley of Cham.ouni runs S9uth-west and north-east, 



inounL parallel to the chain of the Alps, and is bordered by moun- 



Conttins some tains of the primary class. The col de Balme however, that 



©econdary bounds it on the north-east, and mount Lacha, its termina- 

 Btrata. 



tipa ^t the south-west, are composed of slate or calcareous 



^stpnef* This valley contains other secondary rocks likewise, 

 a^s some fine white gypsum, about three miles south-west of 

 the priory, on the borders of the nant or torrent of Tacwiay ; 

 .jjtQj^e limestone opposite the priory, at a place called Biolsiy ; 

 A calcareous l^iid the isolated hill of Piget, in the bottom of the valley, 

 ^^id stretching iiji the same direction, whicli is entirely formed 

 of limestone. These excepted, every thing in thp valley of 

 Chamouni i& of the primitive class. 



Exactly above the priory, on the north-west of the va,ll(^, 



ig mount Breven, the base of which is connected with the 



Aiguilles roviges. Its summit is isylj^ted, and its striata are 



^^t Q§ perpendicularly on ihU side, bjit slojpe gfintjy on the 



... ... , o^hef 



hill, 



BrAveii. 



