62: t REPORT—1849. 
some of the oldest Silurian strata of Merionethshire, he particularly dwelt on the con- 
tinental tracts formerly so rich, as cited by Strabo, all of which (with the exception 
of the North Ural or country of the Arimaspes*, from whence, as Humboldt believes, 
the Scythian ores came) had been exhausted and were no longer gold-bearing di- 
stricts. This circumstance is explained by the Scythian or Uralian gold having re- 
mained unknown from the classical age until this century. So completely ignorant 
were the modern Russians of the existence of gold in the Ural Mountains, or that 
they had in their hands the country which supplied so much gold to Greece and 
Rome, that excellent German miners had long worked the iron and copper mines of 
that chain before any gold was discovered. Even then gold was worked from a solid 
veinstone for some time before the accidental discovery of gold ore in the ancient al- 
luvium or drift led to the superficial diggings, which produced at an infinitely less 
expense the present produce. All the energy however displayed by the Russian 
miners has failed to augment the amount of Uralian gold much beyond half a million 
sterling, and as the period is arriving when the local depressions or basins of aurife- 
rous detritus of that region wil] be successively washed out, the Ural will then re- 
semble many other countries in possessing actual mines of iron and copper, but a 
history merely of its gold. Russia, however, has also the golden key of all eastern 
Siberia, in which various offsets from the Altai*chain (chiefly those which separate 
the rivers Lena, Jenisei, &c., or stretch along the shores of the Baikal lake) have 
proved so very productive in their gravel, that for some years they have afforded the 
enormous annual supply of upwards of three millions sterling, exclusive of the Ural. 
As in the Ural Mountains, so has it proved to be in South America. There, the 
Spaniards, notwithstanding their keen search for gold from the days of Columbus to the 
present time, made many works in the parent rock, but either never discovered its 
existence or neglected to work it in the gravel and sand of the valley of the Sacra- 
mento, which tract they left in quiet possession of the native Indians. It was only 
indeed by the recent accident of the breaking dway of a bank of detritus by a mill 
race, that this region was opened out for the first time to the colonists of the Anglo- 
Saxon race. What then is to be the value and duration of these Californian mines ? 
On the point of absolute value the author does not venture to form an estimate in 
the absence of sufficient facts and statistical data; but in regard to the duration of 
this mining ground, he speculates that granting it to be locally much richer than 
similarly constituted detritus in the Ural, still there is nothing to interfere with the 
belief, founded on the experience derived from all other auriferous tracts, including 
those of Bohemia so productive in the middle ages, that, with the activity and num- 
bers of the men now employed in the works, these deposits may in no great length 
of time be exhausted. 
Judging from analogous facts, he is inclined to think, that the very great per-centage 
of gold ore in the gravel of the valleys of the Sacramento, indicates that the most 
valuable portions of the original veins have been ground down by former powerful 
denuding agencies; and if the rule be allowed which obtains very generally in 
mining, that the richer the veins the less are they likely to be spread over a large 
mass of parent rock, so is he disposed to think, that it will only be in certain patches 
that very great wealth will be discovered, and hence that it would be very wrong to 
conclude, that because rich gold detritus has been discovered on the affluents of the 
Sacramento, in lat. 40°, and also on the river Colorado in lat. 34° 5’, all the interme-- 
diate tract of country should prove productive. Considering the vast addition in the 
few last years made to the European market by researches in Siberia, and seeing that 
such addition has produced no change in the value of gold as a standard, the author is 
of opinion (as far as the evidences allow him to judge), that the Californian discovery 
is not likely to produce any disturbance in the standard. At the same time he ex- 
presses his full agreement with M. Erman and others, that with the advancement of 
colonization in the central regions of North Asia, and other parts of the world 
where civilization has not yet extended, other gold tracts may be discovered, wherever 
the geological and lithological constants to which he has adverted occur; but neither 
* If the gold tracts of the Ural Mountains had been explored and continuously worked from 
the time of Herodotus, they would have been exhausted ages before their occupation by the 
Russians.—R. I. M. 
ry 
