66 
SUPPOSED AUEIFEBOUS KOCKS 
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 ^eat cele- 
brity for metallic wealth. The peak of Calitamini, glowing 
every evening at sunset with a reddish fire, stiU attracts the 
attention of the inhabitants of Maypures. According to the 
fabulous stories of the natives, the islets of mica-slate, situate 
in lake Amueu, augment by their refiection the lustre of 
the nebulse of the southern sky. “ Every mountain,” says 
Raleigh, “ every stone in the forests of t£e 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 quai-tz (“ harde white 
sparr”) ; and to prove the richness of this ore, he gives an 
account of the assays that were made by the ofhcers 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, t that the auriferous quartz 
which he brought home, had not been collected in America. 
"VVe cannot judge of things from which we are separated by 
so long an mterval 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 Gruiana 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 ViUa 
• Messrs. W’eslewood, Dimocke, and Bulmar. 
t See the defence of Raleigh, in the preface to the Discovery of Gui- 
ana, 1596, pp. 2 — 4. 
t In the southern branch of this chain, which passes by Yusma, ViUa 
is Cura, and Ocumare, particularly near Buria, Los Teques, and Los 
Marietas. 
