73 



seeing one of these blocks in the llanos of Vene- 

 zuela, though these immense plains are bound- 

 ed on the south by a group of mountains entire- 

 ly granitic # , and exhibiting in it's denticulated 

 and often columnar peaks traces of the most 

 violent destruction -f-. Toward the north, the 

 granitic chain of the Silla de Caraccas and 

 Portocabello are separated from the llanos by 

 a skreen of mountains, that are schistous be- 

 tween Villa de Cura and Parapara, and calca- 

 reous between the Bergantin and Caripe. I 

 was no less struck by this absence of blocks on 

 the banks of the Amazon. La Cond amine had 

 indeed affirmed, that, from the Pongo de Man- 

 seriche to the strait of Pauxis not the smallest 

 stone was to be found. Now the basin of the 

 Rio Negro and of the Amazon is also but a 

 llano, a plain like those of Venezuela and 

 Buenos-Ayres. The difference consists only in 

 the state of vegetation. The two llanos, situate 

 at the northern and southern extremities of 

 South America, are covered with gramina ; they 

 are savannahs destitute of tress : the interme- 

 diate llano, that of the Amazon, exposed to 

 almost continual equatorial rains, is a thick 

 forest. I do not remember having heard, that 



* The Sierra Parima. 

 + Vol. ii\ p. 461, 468, 469, 540, 568; vol. v, p. 177, 

 016, 676, 687. 



