; 
THE WASHINGTON RIDGE. 413 
altitude, but no bed-rock has been reached. The present bank at one of the most advanced of the 
openings is 260 feet in height, and, with the exception of eight or ten feet of red dirt and voleanic 
débris at the top, is made up of alternating layers of sand, clay, and fine gravel, ranging from two to 
twenty feet in thickness. The material of the gravel and sand is almost exclusively quartz, and there 
is seldom a pebble more than three or four inches through. The water in the sluices, instead of 
being reddish in color, as is so common in gravel mines, was nearly as gray as if it carried nothing 
but tailings from a quartz mill. The lower hundred feet is of a bluish slaty color. There are no 
boulders excepting those of volcanic material which fall from the top of the bank. Some of the 
clay streaks are exceedingly rich in fossil leaves and impressions. There is also considerable 
pyritous fossil wood. The present bank at Gopher Hill is about 240 feet in height. As seen from 
a distance, the top gravel resembles that at Sailor Flat, just described, but much more free from 
sand and clay. Lower down the gravel is coarser and the boulders are larger. Towards the 
bottom the material of the gravel is for the most part metamorphic slate rock, without many quartz 
pebbles. It has a striking resemblance to the gravel at Smartsville, yet wouid be easily distin- 
guished by any one familiar with the appearance of gravel banks. I cannot describe the difference 
in words, any more than I can the differences of the features of two persons who look alike. The 
lowest stratum is a hard blue cement. 
At the Enterprise ground the top bench of light gravel has been removed over an area of about 
eighty acres. The high bank is there nearly three hundred feet high. At one point in the Enter- 
prise ground there was a volcanic top-dirt as much as seventy feet thick in the thickest part. It 
thinned out rapidly on both sides, however, so that the cross-section resembled an old local ravine 
which had become filled by a slide from the central ridge. 
At Sailor Flat there is no recognizable difference of value between the top and the bottom gravel. 
The gold is fine and scaly; but at Gopher Hill the bottom gravel is notably richer in gold, and the 
gold is of a coarser and more massive character. 
There does not seem to be much use in trying to trace the course of any old channel at this 
point until more is known about the relations of the bed-rock. At Gopher Hill I paid some atten- 
tion to the direction of the principal grooves and furrows in the bed-rock, and found it N. 70° W. 
(magnetic). This, however, is not an indication of much value. I will add here that, in the 
opinion of Mr. Hughes and of Mr. Chadwick, there are several nearly parallel gravel streams 
leading down obliquely from the direction of the main ridge, which did not all concentrate at one 
point. The data which I collected at New York Camion, and which will be given on a subsequent 
page, have some bearing upon this view of the question. 
The two sections on Plate O, Figs. 2, 3, are drawn on the same scale as the accompanying map, 
or nearly so. The north and south section (Fig. 2) extends from the South Yuba River to a point 
high up on the ridge above the Blue Tent House. It will be seen that if the bed-rock is level 
from the point “B,” the gravel must be as much as 650 feet thick at the point where the house of 
the superintendent stands. I do not think that the gravel will prove to be of that thickness, for 
it seems most likely that the bed-rock will begin to rise in harmony with the general slope of the 
ridge before that point is reached. 
The east and west section (Fig. 3) has one remarkable peculiarity. It shows a profile across the 
northern end of the deposit, where there is a “ high channel” between Gopher Ravine and Johnson 
Creek, with its bed-rock 145 feet higher than the bed-rock at Gopher Hill. This high channel is 
said, furthermore, to have carried granite boulders, such as have not been met with yet at other 
places in this neighborhood. 
In this connection another diagram (Plate O, Fig. 4) may be given to show a section, north and 
south, through the Sailor Flat mine to the centre of the ridge. I do not have the necessary data 
to make the section an accurate one. ‘The heights and distances are estimated, but are fair approxi- 
mations to the truth. The scale is 500 feet to the inch. The point A is the point on the rim at 
which the observation for altitude was taken. The surface on the flat bench above the gravel bank is 
covered with volcanic débris for a thickness of from five to twenty feet, and there is probably gravel 
