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84 



THE AUBIFEEOUS GEAVELS OF THE SIERRA NEVADA. 



Secret Canon, consists of a hard, gray quartzite, which seems to he a metamorphic form of a rather 

 coarse-grained, quartzose sandstone. The bed-rock at Sterrett's Claim, on the left hank of Sailor's 

 Canon and two miles in a straight line from its mouth, near Canada Hill, is a hard slate striking 

 JS". 35° W., and dipping to the northeast at an angle of 85°. Bald Mountain, a little east of 

 Canada Hill, is entirely made up of an enormous mass of impure quartz-rock. The boulders in the 

 main channel at Canada Hill consist very largely of quartzose sandstone, and there is in the adja- 



cent region a great deal of this material. 



The slates and sandstones about Canada Hill have a 

 nearly east and west strike. In Miller's Defeat Canon, about three miles south of Canada Hill, 

 the boulders are largely of sandstone. At Yule's mine at Startown, near Last Chance, and five 

 miles west-southwest of Canada Hill, the bed-rock varies more or less in character from a soft and 

 light-colored slate, to a very hard and dark-colored material, which may be either slate or sand- 

 stone ; much of this rock is very quartzose, as well as compact and hard. The strike of this rock 

 is pretty uniform in direction, a little to the west of north. The rocks in the bottom of the canon 

 of the North Fork of the Middle Fork of the American River, below Last Chance, are metamor- 

 phic slates, dipping at a high angle to the northeast, and striking northwest. 



A great deal of the bed-rock in the claims near Michigan Bluff is a very talcose slate ; some of 

 it, as at Byrd's Claim, is a kind of semi-serpentine, mixed with very soft talcose slate. In this 

 vicinity the strike of the slates is about north and south, and they stand nearly vertical. There is 

 a region, extending for many miles north from Byrd's Valley, among the forks of Shirt Tail Canon, 

 through Brimstone Plains, and Green Valley, as before noticed, where the bed-rock is almost ex- 

 clusively serpentine. There is a fine locality of this rock, on the line of McKinstry's ditch, south 

 of the North Fork of the American River, nearly east of Clipper Gap, and about a mile northwest 

 of the " United States House." The extent covers an area of 150 feet wide by 300 or 400 feet long, 

 over which the quality of the rock is good ; but the whole mass is much larger. The stone is 

 very beautiful, but more or less seamy. At El Dorado Hill the bed-rock is generally a talcose, 

 and very soft and thin-bedded slate, striking a little to the east of north, and with a variable dip, 

 as if it had been locally disturbed. 



At Smith's Point, between First and Second Brushy canons, near Yankee Jim's, the strike of 

 the slate bed-rock is N. 10° — 15° W. The slates vary from talcose to argillaceous, and stand 

 nearly vertical. At the Dardanelles Claim, a mile and a half southwest of Forest Hill, the bed- 

 rock strikes "N. 35° — 45° W., and stands nearly vertical: some of it is quite hard, and other 

 portions are very soft. 



In the Illinois Canon, near Georgetown, six miles south of Forest Hill, the bed-rock is slate, 

 which is sometimes very thinly laminated and talcose, while other portions are heavy-bedded and 

 argillaceous, so as to pass into a fine-grained sandstone. The more talcose slates are full of cubes 

 of pyrites, and these are said to be rich in gold. The rock is all thoroughly decomposed. These 

 slates have a strike of K 20° W., and dip to the northeast at an anglo of about 55°; they are 

 traversed by a system of joints, underlaying to the southwest at an angle of 45°. At Georgia 

 Slide, near Georgetown, the bed-rock is a rather soft, decomposed slate, generally more or less 

 talcose, and full of decomposed crystals of pyrites. Bald Mountain, between Canon and Otter 

 creeks, three miles north-northeast of Georgetown, is a mass of serpentine, which does not extend 

 far to the east, being succeeded by slates in that direction. At Flora's, two miles west of Volcano- 

 ville, and a little over five miles north of Georgetown, on the extreme end of the spar between 

 Eepublican Canon and the Middle Fork of the American, the bed-rock is quite hard : it has a 

 nearly north and south strike, and stands almost vertical. At the Buckeye-Sucker Claim, about 

 one third of a mile southeast of Mount Gregory, near the head of Otter Greek and eight miles 

 northeast of Georgetown, the bed-rock is a soft decomposed slate striking about 5T. 5° W. and 

 standing nearly vertical. There is a very heavy body of serpentine in the vicinity of Hotchkiss's, 

 at the southeast foot of Mount Oliver, which is about three miles south of Bald Mountain, and 

 some of the same rock at Volcanoville. Serpentine is known to the miners in 101 Dorado County 

 and the southern part of Placer as "hornblende rock." 





