616 
ELEMENTS OE GEOLOGY. 
cases referred to in corroboration can be otherwise interpret¬ 
ed."^ We may, therefore, assert that the most ancient Cor¬ 
nish lodes are younger than the coal-measures of that part 
of England, and it follows that they are of a much later date 
than the Irish copper and lead of Wexford and some adjoin¬ 
ing counties. How much later, it is not so easy to declare, 
although probably they are not newer than the beginning 
of the Permian period, as no tin lodes have been discovered 
in any red sandstone which overlies the coal in the south¬ 
west of England. 
There are lead veins in Glamorganshire which enter the 
lias, and others near Frome, in Somersetshire, which have 
been traced into the Inferior Oolite. In Bohemia, the rich 
veins of silver of Joachimsthal cut through basalt contain¬ 
ing olivine, which overlies tertiary lignite, in which are 
leaves of dicotyledonous trees. This silver, therefore, is de¬ 
cidedly a tertiary formation. In regard to the age of the 
gold of the Ural Mountains, in Russia, which, like that of 
California, is obtained chiefly from auriferous alluvium, it 
occurs in veins of quartz in the schistose and granitic rocks 
of that chain, and is supposed by Sir R. Murchison, MM. De 
Verneuil and Keyserling to be newer than the syenitic gran¬ 
ite of the Ural—perhaps of tertiary date. They observe 
that no gold has yet been found in the Permian conglomer¬ 
ates which lie at the base of the Ural Mountains, although 
large quantities of iron and copper detritus are mixed with 
the pebbles of those Permian strata. Hence it seems that 
the Uralian quartz veins, containing gold and platinum, 
were not formed, or certainly not exposed to aqueous denu¬ 
dation, during the Permian era. 
In the auriferous alluvium of Russia, California, and Aus¬ 
tralia, the bones of extinct land-quadrupeds have been met 
with, those of the mammoth being common in the gravel at 
the foot of the Ural Mountains, while in Australia they con¬ 
sist of huge marsupials, some of them of the size of the rhi¬ 
noceros and allied to the living wombat. They belong to 
the genera Diprotodon and N^ototheriura of Professor Owen. 
The gold of Northern Chili is associated in the mines of Los 
Hornos with copper pyrites, in veins traversing the cretaceo- 
oolitic formations, so called because its fossils have the char¬ 
acter partly of the cretaceous and partly of the oolitic fauna 
of Europe, f The gold found in the United States, in the 
mountainous parts of Virginia, North and South Carolina, 
and Georgia, occurs in metamorphic Silurian strata, as well 
as in auriferous gravel derived from the same. 
* Report on Geology of Cornwall, p. 310. 
t Darwin’s South America, p. 209, etc. 
