CAMPTONVILLE AND VICINITY. 431 
clay resembling the clay derived from basaltic or andesitic material, is in somewhat rounded, worn, 
comparatively thick grains, but has (probably) not been carried far.” 
At the Oshawa tunnel the gravel is paying well, but at the California tunnel no rich spots have 
been struck. The bed-rock appears to be irregular and wavy, with no distinct channel. It seems 
as if the gold must be distributed in spots over an irregularly flat surface, which may or may not 
have been in the path of any stream, but which has been covered with volcanic material during 
the period of volcanic activity. The area of this surface cannot be stated. The California tunnel, 
over nine hundred feet in length, is not yet half-way through the hill. The gravel of Big Oak 
Flat, on the opposite side of the North Yuba, is said to be similar in character to that of Pitts- 
burgh Hill. Further reference will be made to that locality on a subsequent page. 
The present surface of Pittsburgh Hill, and to a depth of three or four feet, is said to have been 
rich in coarse gold. The old miners sank pits until they struck the lava clay, which they sup- 
posed to be bed-rock. It is difficult to account for the gold found on the top of the lava ; perhaps 
it had the same origin as that reported from the top dirt at Depot Hill.* 
The gravel deposits near Oregon Creek, at Tyler’s Diggings and Tippecanoe, a few miles above 
Camptonville, are not of much importance. They are not much higher than the present bed of 
the creek, and they probably owe their origin to the action of the creek itself in connection with 
the cutting away of the Bald Mountain channel at Forest City. Tyler’s Diggings are on the right 
bank of the creek, and lie on both sides of a small ravine. They seemed to be entirely deserted 
at the time of my visit, and I confined my observations to the western bank. The bed-rock at 
this point is a dark-blue clay slate with a northwesterly strike, and a nearly vertical northeasterly 
dip. At the southern end of the diggings the bed-rock is very irregularly intersected witn clay 
seams, and with masses of a whitish or yellowish clayey material. The gravel has extended over 
an area of about 450 by 150 feet, the longer axis being nearly north and south. The present 
northern bank is about sixty feet in height, the lower half being a fine quartz-gravel, containing 
some fossil vegetation, and the upper a sandy clay with red dirt and volcanic boulders, such as 
might have come from the crest of the ridge above the diggings. A few quartz boulders, ranging 
from two to four feet in diameter, lay upon the bed-rock. 
The altitude of the bed of Oregon Creek, where the trail crosses between Tyler's Diggings and 
Tippecanoe, I made to be 3,385 feet, 125 feet below the bed-rock at Tyler’s, and 170 feet below 
that at Tippecanoe. The bed-rock at Tippecanoe is very variable in character within short dis- 
tances. Some of it is soft and rotten, like a decomposed granite ; some is slaty ; and some is soft 
and fragile, breaking with an irregular fracture, like the serpentine of the higher portions of the 
ridge. There are also many seams with a clayey filling, called “tale” by the miners, similar to 
those seen at Tyler's. The gravel is said to extend for a length of 1,200 feet parallel with the 
course of the creek, and to be 600 feet in width in the centre, growing narrower at both ends. At 
the centre of the deposit the banks are about seventy feet in height. The bottom-gravel for a 
thickness of twenty feet is rather coarse, but without large boulders. It contains some rounded 
and some angular pieces of float bed-rock mingled with the blue and white quartz. Considerable 
petrified wood is also found in this lower stratum. Higher up, the bank is composed of finer and 
lighter gravel with a few thin sand-streaks. 
The gravel at the head of Grizzly Cation, two miles and a half above Pike City, is different in 
character from the gravel seen in the old channels. Grizzly Cafion is one of the tributaries of 
Oregon Creek. At its head is a broad flat at the base of the tufa ridge, which rises rapidly about 
a half-mile to the northeast of the mouth of the Grizzly Cafion tunnel. The tunnel is 1,300 feet 
in length, and the drifting extends over an area of about 250 feet in width. The gravel brought 
out to wash contains a great variety of boulders. There is also a peculiar cemented breccia made 
up of angular quartz ; and, in addition, there are blocks of cemented bed-rock. The gold is sharp 
and angular, in spangles “like tea,” or in thin flattened scales, not rolled. In short, there are none 
* For a part of the foregoing information about Pittsburgh Hill I am indebted to Mr. L. A. Pelton, of 
Camptonville. 
