The gold first discovered was evidently not in its original place, but had been washed down from higher regions; and when all that is thus spread through the sands of California shall have been exhausted, if it ever shall be, there are large bodies of auriferous quartz, which (with greater labor and expense) will doubtless afford large supplies of gold for generations to come. The amount of capital invested in quartz-mining, according to the state census of 1852, was about six millions, and in placer and other mining operations, about four millions of dollars; and the sum total of these amounts has been greatly increased since that date. Up to the close of 1851, there had been deposited in the United States mint, $98,407,990 of California gold; and the deposits of 1852 amounted to $46,528,076, making a total of $145,000,000. But all this falls far short of the real amount produced; as probably quite as much more has been sent to Europe in the shape of dust or bullion, not to mention the unreported sums which have been privately taken out of the state. An official estimate states the production of American gold in 1853, at $109,156,748; and of this sum nearly the whole is from the mines of California. And this vast amount is steadily on the increase, in about the proportion of the increase of the mining population, so that California not only is, but is likely to continue to be _the great gold-field_ of the world. Before leaving California, it may not be amiss to add, that the country abounds in mines of almost every kind, as well as gold. Quicksilver, plaster, lead, iron, silver, copper, asphaltum and marble, are found in Butte, and also in Marion county; rich silver mines and coal, in San Louis Obispo; copious salt springs, in Shasta; bituminous springs, in many places along the coast; hot sulphur springs, in Santa Barbara; warm soda springs, near Benicia; and platina is said to be widely distributed in almost every section where gold has been found. Silver has been discovered in several mines in the southern district; copper is widely distributed in other sections beside those above-mentioned; chromium occurs in large quantities in the serpentine rocks; and diamonds are reported to have been recently found in several localities. [Illustration: PLACE WHERE GOLD WAS FIRST DISCOVERED IN AUSTRALIA.]