NOME I. MIAGITE. 



granite ; some of gneiss, others of granite!, or of 

 a rock composed of felspar and hornblende. 

 We see the elements of this granitel sometimes 

 mingled, sometimes separated in the form of 

 layers, some quite white, others quite black; 

 these layers are here straight, there in zigzag, 

 or interrupted by knots or kernels; these acci- 

 dents are generally the same, but less marked, 

 less beautiful, than at the foot of Mont Blanc, 

 892. The most remarkable rocks of this kind, 

 that I saw on the glacier of Lauteraar, are those 

 which enclose other fragments, whose layers cut 

 at right-angles those of the stone or block which 

 enclose them. I also observed roches de corne, 

 or schistose hornblendes, of different qualities ; 

 and the fragments of that rock were covered 

 over with a yellow ochre, occasioned by the 

 oxydation of the iron enclosed in it. Many of 

 s these large blocks were sprinkled with rock 

 crystals, formed in the crevices which had occa- 

 sioned the separation of the rock. These crys- 

 jtals were frequently accompanied with a velvety 

 green earth, or with chlorite."* 



In 1572 he had given an account of the 

 tobies of the river Isere, which runs by Greno- 



* Sauss. 1695. 



