204 



ON CONGLOMERATED ROCKS. 



berg commences immediately after its appearance, 

 as well as the ravine towards Lessoe ; and in these 

 straits, it becomes very remarkable. It generally 

 abounds in mica ; the mica is not scaly-foliated, 

 but in considerable folia, which aVe continuous, 

 and it abounds with beds of quartz. But there 

 is also every where considerable pieces of gneiss 

 dispersed through it, in which the felspar predo- 

 minates ; the mica only appears in separate iso- 

 lated folia, and the quartz very sparingly. The 

 mica in these pieces, forms more straight and paral- 

 lel running streaks, than slate ; while, on the other 

 hand, the slaty composition in the surrounding 

 gneiss is more strongly marked and distinct. These 

 pieces are all angular, and most of them even are 

 quadrangular"; of so considerable a magnitude, as 

 a foot and upwards, and they appear, in fact, very 

 thickly heaped together ; but still in such a man- 

 ner, that we always distinguish the connecting 

 gneiss mass or ground. The streaks of the diffe- 

 rent pieces lying near each other, are often parallel, 

 but they also frequently take completely different 

 directions. They do not consequently follow the 

 direction of the slaty structure of the gneiss which 

 constitutes the basis. This wonderful rock is not 

 a conglomerate, the pieces being too small. The 

 basis is too distinct, and too strongly characterised 

 as gneiss. But it must be owned, that this ap- 

 pearance bears some resemblance to the manner 

 in which the puddingstone is found in gneiss at 

 Valorsine, and in the lower Vallais, according^ 



