358 ' SANTA EULAL1A Book II. 
I cannot say. The formation of the ore seems to have de- 
pended upon the contact of the limestone with the masses 
of porphyry, both repeatedly alternating. In smaller pro- 
portion the layer contains argentiferous galena, and in 
larger masses the carbonate of lead, associated with car- 
bonate of iron. 
These ores were formerly smelted in the valley, and the 
silver gained by cupellation. I witnessed the whole process, 
but have not sufficient technical knowledge to make any 
remarks upon it interesting to the professional metallurgist. 
The process is certainly very imperfect. The ore is con- 
veyed from the mine on the backs of mules, and the labour 
is so hard that many of these animals die in consequence 
during the year. The scenery is wild and peculiar. From 
the height I saw the shafts of several disused mines on the 
opposite mountain, and in the valley the ruins of a place 
called Magellan. 
In the afternoon I explored the mountain on the south 
side of the valley, and followed a stag up to its summit 
without being able to get a shot at it. Here also I observed 
the contact of limestone with porphyry. The latter had, 
in places, been extensively decomposed, and regenerated ; 
in other places its surface was covered with fibrous 
radiated quartz as if with a glaze. Near the summit there 
is a deep ravine, the precipitous sides of which were co- 
vered with the gigantic lily-bearing steins of the yucca — 
an enchanting sight wherever seen. Yuccas, dasyliriums 
opuntias, and agaves covered the mountain sides, with 
many thorny shrubs, acacias, koberlinias, berberis tri- 
foliolata, &c, growing among them. It was the last day 
of March, and all plants which could subsist without the 
summer rains were in full spring beauty. 
Within a space of six English square miles all the moun- 
