1916] 



Dickerson: Tejon Eocene of California 



391 



is exposed for about 4400 feet, and in this distance the descent is 250 

 feet in a west-southwest direction. The form is that of a flat trough, the 

 bedrock rising on the south side 150 feet and on the north side 200 feet 

 and being laid bare throughout. . . . The bottom of the channel is on 

 the whole flat and 700 feet wide. The bedrock is very irregular in detail 

 and covered by large greenstone boulders. The elevation at the upper or 

 east end is about 1250 feet; at the lower end, at the hydraulic bank, about 

 1000 feet. This channel is not the bed of a main river but rather that of 

 a broad and steep gulch. . . . 



At the present bank the channel appears to turn southward and its 

 downward course is in doubt. The gravels at Morris Ravine are of a dif- 

 ferent character. The upper continuation of this channel is likewise in 

 doubt. It is believed that its source was somewhere near Yankee Hill, 

 where there are rich pocket mines, but there are many such deposits in the 

 immediate vicinity, especially near Oregon City, which could supply the 

 gold for concentration in the Cherokee channel. . . . Along the east 

 front of Table Mountain the basalt generally rests on bedrock at an eleva- 

 tion of about 1000 feet. A sharp Neocene slope of 500 feet in a mile 

 carries the bedrock down from Monte de Oro to Morris and Chambers 

 ravines, where several hydraulic and drift mines are located on bodies of 

 gravel once overlain by the basalt of Table Mountain. The elevation of the 

 bedrock at the diggings above the roadhouse on the point of South Table 

 Mountain is 750 feet. On this point an area of about 900 by 150 feet along 

 the rim has been washed. The rim rises 50 feet on each side, forming 

 a distinct shallow trough. The bedrock is greenstone. The bank is 100 

 feet high, showing 50 feet of white sand with extremely well-washed 

 pebbles, mainly of quartz. The sand shows fine fluviatile stratification. 

 This is covered by 50 feet of yellowish clay in horizontal beds and this 

 in turn by basalt. From this point the bedrock remains near an eleva- 

 tion of 620 feet almost to the Yuba mine, where it sharply drops to 580 

 feet. Here there is a considerable hydraulic pit, showing a bank of fine 

 quartz sand with pebbles, underlain by yellowish material containing 

 many pebbles of diabase. . . . Just below this pit, at an elevation of 

 565 feet, the Yuba tunnel extends a few hundred feet in a westerly 

 direction. A slight incline carries it down to bedrock 20 feet below the 

 portal; at this point the bedrock still pitches into the hill. . . . 



A short distance north of the Yuba mine, on the road toward the 

 Goodall and Perkins mine, the Old Glory shaft is sunk 160 feet deep to 

 the greenstone bedrock, which lies at an elevation of about 510 feet and 

 slopes gently west. Coarse, partly angular greenstone gravel was found, 

 apparently containing little gold. The shaft is dry. 



A large hydraulic cut has been made at the Goodall and Perkins 

 mine in the clays and fine gravels of the lone formation, showing a lowest 

 bedrock elevation of about 560 feet. An incline sunk on the rim between 

 the Old Glory shaft and the Goodall and Perkins mine is said to have found 

 bedrock 100 feet lower than in the Old Glory. . 



No bedrock has been found east of these exposures. Heavy masses of 

 clay, with fossil wood, prevail in the south branch of Chambers Ravine. 



There seems to be no large, well-defined channel in Morris Ravine, 

 but an even, rather sharp westward slope, which contained several gullies 

 in which coarser and finer gravel accumulated. They certainly do not 

 represent the continuation of the Cherokee channel. 



