857 



Guyana is owing for the most part to the geo- 

 graphical situation of the country, and the errors 

 of the ancient maps, we are not justified in de- 

 nying the existence of any auriferous land in 

 that extent of country of eighty-two thousand 

 square leagues, which stretches between the 

 Oroonoko and the Amazon, on the east of the 

 Andes of Quito and New Grenada. What I 

 saw of this country between two and eight de- 

 grees of latitude, and sixty-six and seventy-one 

 degrees of longitude, is entirely composed of 

 granite, and of a gneiss passing into micaceous 

 and talcous slate. These rocks appear naked 

 in the lofty mountains of Parima, as w T ell as in 

 the plains of the Atabapo and the Cassiquiare. 

 The granite prevails there over the other rocks ; 

 and, though in both continents the granite of 

 ancient formation is pretty generally destitute 

 of gold-ore, we cannot thence conclude, that 

 the granite of Parima contains no vein, no stra- 

 tum of auriferous quartz. On the east of the 

 Cassiquiare, toward the sources of the Oroonoko, 

 we saw the number of these strata and these 

 veins increase. The granite of these countries, 

 by it's structure, it's mixture of hornblende, 

 and other geological features alike important, 

 appears to me to belong to a more recent forma- 

 tion, perhaps posterior to the gneiss, and ana- 

 logous to the stanniferous granites, the hyalo- 

 mictes, and the pegmatites. Now the least 



