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440 



SUPPLEMENTARY INVESTIGATIONS IN THE GRAVEL REGION. 



which shows comparatively little wear ; there were no pebbles of volcanic origin. The yield of 

 gold is not great, perhaps from twenty-five cents to one dollar per car-load. The indications are 

 that this gravel lies at the head of a ravine which formerly led down from the ridge, and over 

 which the volcanic flow extended. 



The '76 tunnel is about a mile and a half farther east, at the head of Wild Joe Canon. Seen 

 from a point on the opposite side of Kanaka Creek, it appeared to be about 400 feet higher than 



the Crescent tunnel. 



The lava capping grows very narrow at the sag, or divide, between Wolf Creek on the south 

 and Jim Crow Canon on the north. This latter canon is reported to have been extremely rich 

 in early days. At its head, though several hundred feet below the crest of the ridge, are the old 

 Nebraska workings. There is no work now going on at this point, and partly on account of the 

 lack of time, and partly on account of the snow, I made no attempt to study the region ill detail. 

 The descriptions given me by some of the older miners, however, lead me to think that a careful 

 examination would bring to light several features of interest. It is still a question whether the 

 gravel is continuous under the lava between Nebraska and American Hill. 



The American Hill mining claim lies upon both sides of Wolf Creek, the claim next easterly on 

 the southern side of the creek being known as Bunker Hill. The bed-rock is slate, but the line 

 between the slate and the granite to the east is not more than a quarter of a mile away. The bed- 

 rock surface where exposed to view is extremely uneven. I took an observation at the base of the 

 most northerly bank at American Hill, and made its altitude to be 4,880 feet, or 700 feet less than 

 that of the ridge road at the point where the road to the mine leaves it. The altitude of the bed- 

 rock in the cut at Bunker Hill is only 4,700 feet. On the northern side of the creek there is 

 apparently a rim of bed-rock nearly parallel with the present course of the creek ; though farther 

 to the west, below where a bad slide of lava has covered the rim, the channel is thought to recede 

 farther back into the hill, and the spur between Big and Little Wolf Creeks is all gravel. The 

 long tunnels, such as the Whiskey tunnel and the Dutch tunnel, which have been driven in the 

 exploration of the American Hill gravel, are not now accessible. It is said that two channels, a 

 front and a back one, have been recognized, the latter being considerably higher than the former, 

 carrying a different kind of gravel, and yielding a finer quality of gold. There may be some con- 

 nection between these two channels and the two which are reported as being distinguishable at 

 Nebraska ; but their mutual relations have not yet been made out. The front gravel at American 

 Hill is a white quartz, mixed with some blue, and is not much worn ; some of the pieces are still 

 very angular. At Bunker Hill there is considerable float bed-rock in the gravel, and a slide of lava 

 and clay had covered the eastern bank. The lower limit of the lava flow, on the ridge between 

 Wolf Creek and the Middle Yuba, is just above the Bunker Hill gravel. Until mining operations 

 are resumed and the old tunnels are reopened, or new tunnels are driven, it will be difficult to 

 make any satisfactory report, or one that will clear up the doubts which exist in regard to the 

 source of these gravels, or their connection with other deposits either above or below. 



C. Sierra City and Vicinity. 



Sierra City lies upon the South Fork of the North Yuba Biver, a short distance below the junc- 

 tion of a northerly and a southerly branch, thirteen miles above Downieville, and at the southern 

 base of the Sierra Buttes. The town is built in the canon, near the level of the stream. Its alti- 

 tude, at the Yuba Gap House, is 4,175 feet. To the south of the town rises the high northeasterly 

 extension of the Forest City ridge. I did not determine the altitudes of any of the highest points 

 in this vicinity on account of the snow. 



The bed-rock between Sierra City and Downieville, so far as exposed to view in the canon and 

 along the stage road, is an easily cleavable slate. About four miles above Sierra City, on the Sierra- 

 ville road, there is a change to granite; and the easterly portion of the slate is, in places at least, 

 much more compact and much less easily cleaved than are the portions farther west. In crossing 

 the ridge which lies between Sierra City and Sierraville I saw no bed-rock at all on the eastern 



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