396 PRODUCE OF GOLD. 
and ten times as much as is furnished by all the 
mines of Europe. 
On the other hand the produce of the Mexican 
mines in gold is not much greater than those of 
Hungary and Transylvania; amounting in ordinary 
years only to 4315 troy pounds. In the former it is 
chiefly extracted from river-deposites by washing. 
Auriferous alluvia are common in the province of 
Sonora, and a great deal of gold has been collected 
among the sands with which the bottom of the val- 
ley of the Rio Hiaqui, to the east of the missions of 
Tarahumara, is covered. Farther to the north, in 
Pimeria Alta, masses of native gold weighing five 
or six pounds have been found. Part of it is also 
extracted from veins intersecting the primitive 
mountains. Veins of this metal are most frequent 
in the province of Oaxaca, in gneiss and mica-slate. 
The last rock is particularly rich in the mines of Rio 
San Antonio. Gold is also found pure, or mixed 
with silver-ore, in most of those which have been 
wrought in Mexico. 
The silver supplied by the Mexican veins is ex- 
tracted from a great variety of minerals. Most of it 
is obtained from sulphuretted silver, arsenical gray- 
copper, muriate of silver, prismatic black silver-ore, 
and red silver-ore. Pure or native silver is of com- 
paratively rare occurrence. 
Copper, tin, iron, lead, and mercury, are also pro- 
cured in New Spain, but in very small quantities, 
although it would appear that they might be found 
to a great extent. The mercury occurs in various de- 
posites, in beds, in secondary formations, and in veins 
traversing porphyries ; but the amount obtained has 
never been sufficient for the process of amalgamation. 
