66 SUPP'JSED AUBIFEEOUS BOCKS 



that it may not contain very metalliferous transition rocks 

 and mica-slates superimposed on the granite. 



I have already observed, that the silvery lustre and fre- 

 quency of mica have contributed to give Gruiana great cele- 

 brity for metallic wealth. The peak of Calitamini, glowing 

 every evening at sunset with a reddish fire, still attracts the 

 attention of the inhabitants of Maypures. According to the 

 fabulous stories of the natives, the islets of mica-slate, situate 

 in lake Amucu, augment by their reflection the lustre of 

 the nebulse of the southern sky. " Every mountain," says 

 Raleigh, " every stone in the forests of the Orinoco, shines 

 like the precious metals ; if it be not gold, it is madre 

 del oro (mother of gold)." Raleigh asserts that he brought 

 back gangues of auriferous white quartz ("harde white 

 sparr") ; and to prove the richness of this ore, he gives an 

 account of the assays that were made by the officers of the 

 mint at London.* I have no reason to believe that the 

 chemists of that time sought to lead Queen Elizabeth into 

 error, and I will not insult the memory of Raleigh by sup- 

 posing, like his contemporaries,f that the auriferous quartz 

 \vhich he brought home, had not been collected in America. 

 We cannot judge of things from which we are separated by 

 so long an interval of time. The gneiss of the littoral chainj 

 contains traces of the precious metals ; and some grains of 

 gold have been found in the mountains of Parima, near the 

 mission of Encaramada. How can we infer the absolute 

 sterility of the primitive rocks of Guiana from testimony 

 merely negative, from the circumstance, that during a jour- 

 ney of three months we saw no auriferous vein appearing 

 above the soil ? 



In order to bring together whatever may enlighten the 

 government of this country on a subject so long disputed, I 

 will enter upon a few more geological considerations. The 

 mountains of Brazil, notwithstanding the numerous traces of 

 imbedded ore which they display between Saint Paul and Villa 



* Messrs. Westewood, Dimocke, and Bulmar. 



t See the defence of Raleigh, in the preface to the Discovery of Gui- 

 ana, 1596, pp. 2 4. 



J In the southern branch of this chain, which passes by Yusma, Villa 

 is Cura, and Ocumare, particularly near Buria, Los Teques, and Los 

 Mar let as. 



