

BETWEEN NORTH BLOOMFIELD AND EUREKA. 



405 



h 







for the remaining 800 feet. The tunnel was driven for the sake of opening a drift mine, not for 

 hydraulic sluices. At a distance of 523 feet from the mouth of the tunnel a rise was made, and 

 gravel was struck seventy feet above the tunnel. At 500 feet farther in gravel was found only 

 seven feet above the top of the tunnel, and this distance seemed to remain nearly constant to the 

 end of the tunnel. Some drifting was done in blue gravel mixed with large smooth boulders, 

 for a few months, but for some reason the work has been discontinued. The bed-rock was Hat 



and level. 



The only other places at which I took observations for altitude were at Mr. Penrose's house and 

 at the mouth of an old shaft in the Eagle claim, where it was said to be sixty feet to bed-rock. 

 If this last statement bo true, the bed-rock in the Eagle ground is fifteen feet lower than the mouth 

 of the Great Eastern tunnel, the altitude at the mouth of the shaft being made to be 3,758 feet, 

 and about fifty feet lower than the bed-rock at the farther extremity of the tunnel. So far as 

 these observations have any value, they point to a probable course of the stream at this point more 

 northerly than I had supposed, if it has a fall in the general direction of Bloomfield, or the Derbec 

 Shaft, as is more likely the case. Any alternative supposition, which would select a more southerly 

 course for the channel and make it sweep around more nearly parallel to the course of the present 

 South Yuba, will have to bo excluded, both on account of the topographical features of the country 

 and on account of the great difference of altitude between Relief Hill and Bloomfield. If the 

 gravel at the Derbec Shaft be supposed to be on the continuation of the channel from Relief Hill, 

 the grade between the two places will be but little more than the average grade of the old stream 

 for its whole length from Snow Point to Timbuctoo. The precise distance from Relief Hill to the 

 Derbec Shaft cannot be given, but it will not exceed three miles nor fall much below it The 

 difference of level of bed-rock between those points I make to be 345 feet, — say 115 feet to 

 the mile. The principal objection to the hypothesis of a connection between Relief Hill and the 

 Derbec Shaft is that it requires the stream to follow a more northerly course than the old streams 

 usually followed, —an objection less serious, it seems to me, than those which can be urged against 



other hypotheses. 



The highest banks exposed at present, those in the Eagle claim, arc from 100 to 150 feet in 

 height From twenty to forty feet of the top of these tanks are made up of red dirt and volcanic 

 boulders, the excavations not yet extending back to the lava in place. Below this there comes a. 

 stratum of white gravel, composed of fine quartz with small streaks of sand and clay, not cemented, 

 which, certainly on the northeastern rim, reaches quite down to the bed-rock. In some places the 

 white gravel must be as much as 140 feet thick. Below the white gravel there is said to be a blue 

 gravel on the deepest bed-rock, reached only by means of the shaft. 



The gold found at Relief Hill is mostly fine. In the Union claim nuggets worth from five to ten 



dollars are said to have been found, though rarely. 



In regard to the drift mine at Mount Zion then; is not much to be said. Work has been carried 

 on here at intervals for more than twenty years, but no one seems to have had the courage to 

 thoroughly test the property, and to settle the question whether there is or is not a deep gold- 

 bearing channel under the lava. The main tunnel runs nearly due west for a distance of 1,400 

 feet, rising in that distance twenty-four feet. The tunnel is entirely in bed-rock, a hard meta- 

 morphic slate. At the farther extremity of the tunnel there is an incline with a vertical rise of 

 fifty-two feet, followed by a short, nearly level drift to the gravel. From the point where the 

 gravel is struck there has been a drift run in a northerly direction for six hundred feet. This 

 drift is supposed to follow the rim, for the bed-rock has a strong pitch to the west. The material 

 of the gravel in this drift is almost exclusively quartz, with occasional bits of slate, well washed 

 and rounded. The «ravel is not very coarse, pebbles of three or four inches in diameter being 



among the largest. 



The gravel is not cemented. 



To the south of the main tunnel prospecting has been carried into what may be regarded as a 

 branch or overflow. It was at this point that breasting was going on when I was there. The pay- 

 streak is about three or three and a half feet thick, and on the bed-rock the gravel is frequently 





