138 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
where placer gravel mining has been carried on, off the line of the Table 
Mountain channel just described. At Chinese Camp there is a flat, or level, 
area some three miles in length and covered with detrital material to the 
depth of from three to five feet, which has been mostly worked out ; 
although as late as 1872, according to Mr. Skidmore, furnishing employment 
to a considerable number of Chinese, and likely to do so for several years to 
come. Some spots were found to be very rich; but these have long since 
been exhausted. In this vicinity a number of patches of cemented gravel 
occur on the summits of the higher spurs. One of these, situated immedi- 
ately to the east of Chinese Camp and about 180 feet above the level of the 
Flat, and covering an area of about ten acres, is said to have been exceed- 
ingly rich, the pay gravel, which was of a blue color, varying from one to 
twenty inches in thickness and lying immediately above the bed-rock.* 
Two miles northeast of Chinese Camp is the town of Montezuma, which 
was once noted for its rich placers, the gravel covering several small irreg- 
ular patches to the north and east of the town and a larger one between it 
and Table Mountain, which runs about a mile to the west. The thickness of 
the gravelly material was here, in places, as much as fifty feet. Between the 
Stanislaus River and Wood’s Creek there are various gravel areas, but no 
one so extensive as that to the west of Montezuma. Jamestown, on Wood’s 
Creek, was once the centre of an active placer mining population, the bed 
of that creek having been exceedingly rich, and many small patches of 
gravel yielded largely, although not usually over two feet in thickness. 
It is said that the sales of gold at Jamestown for several years averaged over 
a thousand dollars a day. 
The whole surface of the limestone belt between Kincaid Flat and the 
Stanislaus, already described, has been worked over and nearly or quite 
exhausted, in all the localities where the deeply eroded cavities in this rock 
could be got at, without too much expenditure for drainage. Columbia, 
three miles northwest of Sonora, was for some years the centre of activity 
in this mining region. It is situated on the limestone belt, in the midst of 
what was once a beautiful valley; but which now presents a most extraor- 
dinary appearance, the soil and detrital accumulations, which once covered 
over the underlying rocks, having been entirely removed, over the whole 
extent of the belt, so that nothing is to be seen except the projecting tops 
of the ragged edges of the eroded limestone, rising sometimes fifteen or 
* W. A. Skidmore, in Fourth Annual Report of the Commissioner of Mining Statistics, p. 60. 
