MODE XI. GNEISS. 



Gneiss, with white felspar, from the same coun- 

 tries, Salzburg, Greece, &c. It is a common, and 

 seems a fundamental rock in the Brasils. Mr. 

 Jameson says, that it is found in the isles of Coll, 

 Tirey, and Rona; also in the Shetland isles, and 

 many parts of the main land of Scotland. 



Aspect 2. Undulated. This is more uncommon 

 than the former. 



Undulated red gneiss, from the Alps of Dau* 

 phiny. 



The same, singularly contorted, from the same 

 site. This forms a remarkable diversity. 



Red gneiss, from Norway. 



Grey undulated gneiss, from the same countries. 



STRUCTURE III. IRREGULAR. 



In this kind the layers intersect each other irre T 

 gularly, in the form of wedges, &c. It differs 

 from the veined granite of Saussure, because the 

 divisions do not terminate in massy portions, but 

 are continued in oblique and irregular directions. 



Red irregular gneiss, from the Alps, Norway, 

 &c. 



Grey, from Brasil, and other countries. 



