follows:

In 1849, $4,921,250; in 1850, $27,676,346; in 1851, $42,582,695; in
1852, $46,586,134; in 1853, $57,331,034; in 1854, $51,328,653; in 1855,
$45,182,631; in 1856, $48,887,543; in 1857, $48,976,697; in 1858,
$47,548,025; in 1859, $47,640,462; in 1860, $42,303,345; in 1861,
$40,639,089; a total of $551,603,904 in twelve years.

The exportation of gold commenced in 1848, but we have no record of the
sums sent away in that year. Previous to 1854 very large sums were
carried away by passengers, who gave no statement at the Custom House;
since that year, the manifests show the exportation correctly within a
few millions. I am entirely satisfied that the total gold yield of
California has been not less than seven hundred millions of dollars;
but I have not room here to state the reasons for this opinion. My
estimate is considerably less than that of most business men of the
state, and less than that made by Hunt's _Merchants' Magazine_. There
was undoubtedly a regular increase in the annual yield of the mines
from 1848 to the end of 1853; and there has been a gradual decrease
since the beginning of 1854--a decrease perhaps not very regular but
still certain. Since 1854 considerable sums exported from San
Francisco, and included in our tables, came from mines beyond the
limits of California, such as the mines in Southern Oregon, in the
eastern part of Washington Territory, in British Columbia, and in
Nevada Territory; and while the California gold yield has been
decreasing, these extraneous supplies have been increasing. Several
millions must be deducted from the annual shipments since 1858, for
foreign gold. The gold yield will undoubtedly continue to fall, but to
what point and at what rate no one can know. I believe that in 1870,
the yield will not exceed thirty millions of dollars.

_Placer Mines._--Placer mines are divided into many classifications.
The first and most important is into deep and shallow. In the former
the pay-dirt is found deep, twenty feet or more beneath the surface; in
the latter, near the surface. The shallow or surface diggings are
chiefly found in the beds of ravines and gullies, in the bars of
rivers, and in shallow flats; the deep diggings are in hills and deep
flats. The pay-dirt is usually covered by layers of barren dirt, which
is sometimes washed, and sometimes left undisturbed, while the pay-dirt
is taken out from beneath it through tunnels or shafts. So far as our
present informati