604 



the chain of the shore of Venezuela, where 

 granite seems to constitute an independent for- 

 mation from 15 to 16 leagues in length, I saw 

 no foreign or subordinate layers of gneiss, mica- 

 slate, or primitive limestone *. 



The Sierra Parime is one of the most exten- 

 sive granitic soils existing on the globe -f - ; but 

 the granite which is seen alike bare on the 

 flank of the mountains, and in the plains by 

 which they are joined, often passes to gneiss. 

 (Vol. iv, p. 552.) Granite is most commonly 

 found in its granular composition, and inde- 

 pendent formation, near the Encaramada (Vol. 

 iv, p. 462), at the strait of Baraguan^ (Vol. iv, 

 p. 502), and in the vicinity of the mission 

 of the Esmeralda. It often contains, like the 

 granites of the Rocky Mountains (lat. 38°— 

 40°), the Pyrenees, and Southern Tyrol, am- 

 phibol crystals disseminated in the mass, 



* Primitive limestone, every where so common in mica- 

 slate and gneiss, is found in the granite of the Pyrenees, at 

 port d'Oo, and in the mountains of Labourd (Charpentier, 

 sur la const, geogn. des Pyrenees, p. 144, 146. 



f See above, Vol. vi, p. 501, 520. To prove the extent 

 of the continuity of this granitic soil, it will suffice to ob- 

 serve that M. Lechenault de la Tour, collected in the bars of 

 the river Mana, in French Guyana, the same gneiss gra- 

 nites (with a little amphibol) which I observed three hun- 

 dred leagues more to the west, near the confluence of the 

 Oroonoko and the Guaviare. 



t 1 did not observe this mixture of amphibol in the gra- 



