

486 



SUPPLEMENTARY INVESTIGATIONS IN THE GRAVEL REGION 



rock has a more rapid westerly pitch than the surface of the basalt ; and that under the cap there 

 is probably a wedge-shaped mass of detrital material, of unknown thickness on the west and gradu- 

 ally growing thinner towards the east. At Cherokee Flat the gravel is certainly very rich in gold, 

 and the former richness of the Morris Ravine placers, the material of which probably came from 

 under the basalt, indicates that the wdiole mass of detritus is auriferous. But the fact that, while 

 the gravel of Cherokee Flat, with the exception of the large boulders, is almost exclusively quartz, 

 there is scarcely any quartz to be seen in the gravel of the western slope of the South Table Moun- 

 tain, is sufficient to raise a doubt as to the uniformity of the distribution of the gold. This doubt 

 is still further increased by the differences in the surface-dirt of Schermcr's and Morris ravines, 

 which stand in almost identical relations to the cap of basalt. By some persons it is supposed that 

 there is a true gold-bearing, old river channel, with a north and south course, connecting Cherokee 

 Flat with Morris Ravine. I do not feel satisfied that this is the case. In the first place, the, 

 gravel of Cherokee Flat lacks the peculiar arrangement and structure of the river gravels ; and, in 

 the second place, there are no similar gravel deposits, so far as I could learn, within a radius of 

 several miles at least, with which the Cherokee Flat gravels could have ever had any connection. 

 From the top of Table Mountain an excellent and extensive view of the high mountains to the north- 

 east can be had ; but nowhere in that direction for many miles are there any gravel deposits at all. 

 Walker's Plains, or u Walker's Lava-beds," distant about eighteen miles in an air-line, are said to 

 be covered with basalt like that of Table Mountain, and it is very probable that they once formed 

 parts of the same lava-flow. From Walker's Plains on a clear day the water in the Table Moun- 

 tain reservoirs can be seen. At higher altitudes in the mountains, at the "gravel range," and at 

 Lott's Diggings, near the line between Butte and Plumas counties, there are reported to be gravel 

 deposits in some respects resembling that of Cherokee Flat, though not identical with it. The 

 higher portions of Butte County are much cut up by deep canons, and the region is one difficult 

 of access ; an entire season might well be taken for the study of its detrital formations. v 



It was a part of my plan to extend my trip as far north, at least, as Dogtown (Magalia P. 0.), 

 fifteen miles from Cherokee Flat, but the commencement of the rainy season prevented my putting 

 the plan into execution. The gravels at St. Clair Flat, between Cherokee Flat and Pence's' Ranch, 

 were the only ones in that direction to which I paid any attention. The bed-rock along the stage- 

 road from Cherokee to St. Clair Flat is an easily cleavable slate. To the west and south of the 

 road the bed-rock soon disappears under the surface and is not seen again, either on the flank of 

 Table Mountain or in the valley. The gravel deposits of the Flat, and along Dry Creek, where it 

 emerges from the mountains, are of considerable extent, superficially, but they belong to a different 

 class of deposits from that at Cherokee Flat. They do not seem to be confined to particular chan- 

 nels, but to form part of the general detrital material of the valley. The altitude of the bed-rock 

 at one opening I made to be 765 feet, at another 735. The first large excavation to the north of 

 the road, that I saw on my way down from Cherokee, was in a bank of gravel resting against the 

 base of a bed-rock hill. The opening was nearly a quarter of a mile in length, but of no great 

 width. The gravel was lightly cemented, and resembled a breccia rather than a conglomerate. In 

 a few places it was blue in color, though generally reddish and brownish. It was not quartzose. 

 The boulders, some of them as much as six or eight feet in diameter, were heterogeneous in char- 

 acter. Specimen 162 represents a common variety. Welch's Bank, on Dry Creek, lies at the foot 

 of or under one of the beds of black volcanic conglomerates of which so many are seen, like beach- 

 marks on the hills of this vicinity. The face of the bank showed at bottom fifteen feet of gravel, 

 containing but little if any quartz ; then came about thirty foot of a dark drab or slate-colored 

 clay, with here and there thin streaks of gravel ; above this there was a stratum, about thirty-five 

 feet in thickness, of a very dark, nearly black, finely cleavable or horizontally laminated, clayey, 

 carbonaceous material, which might be described as a sandy and sulphurous impure lignite. It 

 effloresces on exposure to the air. The bank does not carry gold enough to pay for moving the 

 whole mass by the hydraulic process. Drifting operations have been begun. On the bed-rock the 

 gravel is reported to contain about fifty cents worth of gold to the car-load. 



