AURIFEROUS VEINS IN NEW MEXICO AND THE GREAT BASIN. 
95 
yet occupied by another, he has to apply to the nearest alcalde, (justice of the peace of the 
district,) who, according to the means and intended work of the individual, allows him a 
smaller or larger tract of land, measured only in front, and reaching in depth as far as the 
owner pleases to go. The price of the land is trifling ; hut if the owner does not work a certain 
portion of the mine every year, it falls hack to the government.” “ Foreigners were, in conse¬ 
quence of the eternal revolutions and new law codes in Mexico, sometimes excluded, sometimes 
allowed to participate in this privilege.” “ By taking a Mexican as partner, they obviated the 
law ; hut the most dangerous enemy was generally the avaricious Mexican government itself. 
Often, when a foreigner had opened a profitable mine, these trustees of justice interfered for 
some reason or other, and ejected the owner of his property. Several instances of such proceed¬ 
ings are known. If we add to these causes the isolated situation of New Mexico, the thin 
population, the want of good mechanics and real miners, the hostilities and depredations of the 
Indians, it will not astonish us at all that, notwithstanding the great mineral resources of the 
country, so few mines are worked at present.” 1 
Quartz veins .—There is one specimen of “ auriferous quartz” from the new placer in the 
collection, (No. 93 of the catalogue.) On examination, as will he seen from the description in 
another place, no gold could he detected by the eye, hut the rock was cellular, and stained with 
oxide of iron, proceeding from the decomposition of pyrites. I do not find any description of 
the vein from which this was procured in Mr. Marcou’s notes. He, however, mentions the 
occurrence of copper ores, which are probably auriferous, hut from the specimens in the collec¬ 
tion I judge that they are from another vein. The direction of the new placer is also given in 
the notes as east 30° north ; hut whether this refers to the direction of the auriferous valley or 
to the auriferous veins, is rather uncertain. 
Quartz veins, hearing gold, are, however, mentioned and described by both Abert and Wis- 
lizenus, and also by Gregg. The former visited a mine somewhere in the old placer, north of 
Tuerto, and found the gold to he in a quartzose rock in particles visible to the naked eye. 
This auriferous quartz was first broken into fragments, and then crushed by a rude mill or 
arastra . 2 Lieut. Abert also visited another mine further south. This he calls a copper mine, 
and specimens of the ore were seen about the entrance. By pounding up some of this, however, 
between two stones, and washing, particles of gold and silver were visible. The vein is said to 
he in compact limestone. The sides of the passages of the mine were very irregular, and cut 
into deep rounded fissures which were called pockets, and in which the richest ores were said to 
occur. Lead ore and carbonate of lime were also seen at this place. At another mine—one 
belonging to Mr. Campbell—the ore was composed of a very porous and vesicular rock, which 
was easily crushed. The vein is reported to he nearly horizontal, and trends a little north of 
west, (N. 80° W.,) 3 and traverses compact limestone. The sides of the mine are full of pockets. 
Mr. Campbell informed Lieutenant Abert that the ore near the surface was the richest, and that 
the yield in gold diminished on going to a great depth, so that it hardly paid the expenses. 
This is probably due to improper treatment of the ore. That found near the surface being 
partly decomposed, yields up the gold more readily and with less care than the undecomposed 
portions from a greater depth. This conforms to the universal experience with veins of auriferous 
pyrites, the decayed parts of the vein being the most profitable. With regard to the working 
of these mines, Lieutenant Abert observes: ‘'These mines are much more extensively worked 
than those of Real Viejo ; and, notwithstanding the scarcity of water, I have been told by 
several persons that not less than two thousand people congregate here in the winter season 
1 Wislizenus’ Memoir of a Tour to Northern Mexico, p. 32. 
3 A peculiar mill for grinding ores, used principally in Spain, South America, and Mexico, and formed by attaching heavy 
slabs of rock by chains to the ends of long beams projecting from an upright spindle, which being made to revolve, drags 
the slabs around in a circular pit or trough lined with iron or stone, into which the ore is thrown, with water and quick¬ 
silver. 
3 This direction is given in a corrected copy of Lieutenant Abert’s Report. It is printed N. 50 - W. 
