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THE DIVIDE BETWEEN SLATE AND CANON CREEKS. 457 
main stream from Howland Flat, for, between the ravine and the crest of the ridge, gravel has 
been found, and drift mining has been carried on at several places. I cannot speak of this branch 
channel from personal observation, but it seems to have taken its rise somewhere near Table Rock. 
The St. Louis gravel, between Cedar Grove Ravine and Sackett’s Gulch, has been worked to a 
considerable extent by the hydraulic process, particularly at the northern and the southern ends 
of the field. The central portion, where the town stands, has hardly been touched. The gravel is 
favorably situated for mining, but the process of washing will go on at a slow rate, unless the 
available quantity of water be in some way increased. ‘The altitude of the bed-rock at the lower 
end of the mines, near Cedar Grove Ravine, is 4,993 feet. 
Between Sackett’s Gulch and Harris Gulch the town of Chandlerville used to stand, but there 
are no houses there now, and the gravel deposit is exhausted. Pine Grove also was once one of 
the principal mining towns of this vicinity; but since its destruction by fire it lias never been 
rebuilt. It is at this place that the most of the Slate Creek water is at present used. Mr. G. W. 
Cox, of the Sears Union Company, says that in the busy season the supply of water amounts to 
three or four thousand inches. The altitude of Mr. Cox’s business office I made to be 5,486 feet, 
and that of the bed-rock in the Pine Groves mines, about midway of the present opening, 5,396 
feet. The gravel in these mines has been disturbed in several ways since it was first deposited. 
Just back of Pine Grove there is a small sugar-loaf knoll of volcanic material, standing by itself, 
quite detached from the main voleanic capping at Table Rock. Whether this represents an ancient 
slide from the higher ridge or not cannot be told with certainty, but there is evidence that there 
has been a flow of lava or mud to cut away a part of the original gravel. There is also a so-called 
“horse” of similar material on the old rim of the channel, on the side opposite to the Sugar Loaf. 
The section (Plate S, Fig. 4) is not drawn to scale, but shows the relations of the gravel and lava 
as I sketched them roughly on the spot. I have Mr. Cox’s authority for saying that the presence of 
gravel under the eastern body of lava has been proved by drifting. In this connection I will add 
that I was told by Mr. Wallis, the superintendent of the Bald Mountain Company at Forest City, 
of a mass of lava at Pine Grove, “like a bell upside down,” which covered gravel under its rim on 
all sides, without there being any bed-rock discoverable under the apex of the bell, even though 
tunnels were driven in and shafts sunk. I did not make the acquaintance of Mr. Wallis until 
after I had left this part of the country, and could not return for any revision of my work. An- 
other interesting occurrence at Pine Grove is that of gravel in thin seams, two or three inches 
wide, in bed-rock. The quartz fragments which this gravel contains are angular. 
Above Pine Grove the old channel is traceable through Howland Flat to Potosi, though its 
precise winding course cannot be shown upon any published map. A detailed topographical map 
on a large scale is needed. Howland Flat is not quite a mile from Pine Grove, and Potosi is about 
half a mile to the east of Howland Flat. The altitude of the lower floor of Becker’s Hotel, at the 
latter place, I made to be 5,600 feet, and that of the mouth of the Bonanza tunnel, at Potosi, 5,655 
feet. There are everywhere signs of former mining activity. At Howland Flat there have been 
both hydraulic and drift mines. The banks now exposed to view to the north and west of the 
town are small and low, and do not appear to have been worked very recently. The drift mines 
at Potosi have been developed pretty extensively. Tunnels have been driven in a northeasterly 
direction, in the hope of finding the continuation of the old channel under Alturas Mountain, and 
other tunnels, like the new Bonanza, have been made to follow a more easterly or southeasterly 
course, on the hypothesis that the channel came across the ridge near where the low gap now is 
between Table Rock and Alturas. To go through all the mines and collect data for a satisfactory 
independent judgment would require several days’ time. The Bonanza tunnel was the only one I 
was able to visit, though I could easily have obtained access to others. This tunnel follows a 
course N. 83° 30/ E. (magnetic) for 1,547 feet, and then S. 65° 51’ E. (magnetic) for 2,289 feet 
farther, rising, in the whole distance, twenty feet. The tunnel was started in volcanic material, 
the probable position of the gravel being pretty well known from the developments in the adjoin- 
ing claim, the Empire. The successive rock formations met with in the tunnel are as follows : — 
