452 



SUPPLEMENTARY INVESTIGATIONS IN THE GRAVEL REGION. 



between the forks of Slate Creek, and also between Slate Creek and Wallis Creek. There is, 

 therefore, no natural outlet now open, except through the narrow canon of the North Fork of Slate 

 Creek. Possibly some light might be thrown on this question by a careful examination of the 

 Chalcedonia and Boot-jack tunnels, which lie to the southwest of the town of Gibsonville, on the 

 opposite side of Gibson Creek. Work is now suspended in these tunnels, and I did not make any 

 attempt to enter them. From the best information I could get I judge that the bed-rock maintains 

 its downward grade to the southwest beyond the natural outlet above mentioned ; and if so, the 

 channel must extend under the volcanic capping, to reappear at some point lower down, possibly 

 as far down as La Porte. No more positive information can be given at the present time, nor is 

 anything definite known in regard to the extension of the channel above Hepsidam. The crest of 

 the ridge, a half-mile to the northwest of Bunker Hill, has an altitude of 6,750 feet, the top of 

 Bunker Hill being about 250 feet higher. The bed-rock directly underneath is probably 150 feet 

 above the mouth of the upper tunnel. This leaves 600 feet for the thickness of gravel, clay, and 

 volcanic material at this point. The crest between Bunker Hill and Pilot Peak is a part of the 

 water-shed between the Yuba and the Feather rivers. To the east and northeast the surface of the 

 ground falls off rapidly into the valleys and the canons of the head-waters of the Feather. Blue- 

 nose Mountain is the only prominent high point to the east, of an altitude sufficient to justify any 

 expectation that the extension of the gravel channel might be found under it. Standing upon this 

 crest I could see nothing to serve as a guide in any further explorations ; I seemed to have reached 

 the end. If the sources of the old channel were still farther to the east or northeast, the evidences 

 of their existence are all gone. The course of the channel, even with only a slight upward grade, 

 would pass quite above the tops of almost all the peaks in sight. I did not make any attempt to 

 study the northeastern slope of the ridge, and do not know of any outcropping gravel beds on that 

 side. Having traced this channel to its highest known point, I must leave it. If we suppose the 

 channel came in under Pilot Peak, we shall be equally at a loss to tell where it came from. 



The water-supply of this region, including both the La Porte and the Gibsonville sub-districts, 

 is small. In winter there are heavy falls of snow, which frequently accumulates to a depth of 

 twenty feet or more. With the melting of the snow active mining operations begin. Some efforts 

 have been made to bring water from the Feather River by piercing the ridge with tunnels. 

 One tunnel, 500 feet in length, cuts through the ridge, near the Onion Valley road above Gibson- 

 ville, and another has been begun, to take water from Little Grass Valley through the ridge to La 

 Porte. When completed this latter tunnel will be over 4,000 feet in length. At Mount Pleasant, 

 in the height of the season, a supply of between 1,500 and 2,000 miner's inches of water from all 

 sources may be counted Upon, The smallncss of the supply of water affects unfavorably the mode 

 of working the gravel. The sluices are short, the sluice-boxes are narrow, and the grade is high. 

 There are no such extensive arrangements for saving gold, no such long sluices nor elaborate sys- 

 tems of undercurrents, as are to be seen in Nevada County. 



Another drawback to success in mining seems to be the uncertainty of mining titles, to which 

 may be added the lack of concentrated effort on the part of the miners. If all litigation were 

 brought to an end, and the smaller claims were consolidated under one management, the ground 

 could be worked with much greater profit than it now is. 



B. From Council Hill to Howland Flat; the Divide between Slate Creek and 



Canon Creek. 



Slate Creek and Canon Creek are nearly parallel to each other from their sources, on opposite, 

 sides of Alturas Mountain, to their junctions with the North Yuba. The ridge between them is 

 narrow and steep, the streams being sometimes less than two miles apart, while the ridge is more 

 than a thousand feet in height. The gravel deposits on this ridge, together with those near 

 La Porte and Gibsonville, make up what is frequently called the Slate Creek Basin, though below 

 Poverty Hill the natural outlet of the mines is into Canon Creek. The map (Plate R) shows the 

 principal features of the ridge. The vicinity of Poverty Hill and Scales's Diggings is shown on a 





