LINUGREN.] 



GRAVELS OF MOORE CREEK VALLEY. 



663 



covered by auriferous gravels which have 

 a thickness of 60 feet or less. The base 

 of these gravels lies, at Barker's claim, 300 

 feet above Moore Creek. This gravel shows 

 excellent fluviatile stratification, and appears 

 to rest in a flat channel eroded in the lake 

 beds. The gravel consists of well-washed 

 granite pebbles, accompanied by some of 

 quartz. Bowlders 2 feet in diameter occur 

 occasionally. This gravel is quite rich, the 

 best pay being found, as usual, on the bed 

 rock, i. e., on the soft lake beds, but there is 

 also gold distributed through the gravel. 

 The gravel and gold has also, of course, slid 

 down the steep hillside, and this material 

 covering the slopes has been washed. Dur- 

 ing the summer of 1896 the claim of Mr. 

 Barker, 1 mile southeast of Idaho City, was 

 worked by the hydraulic process. The pay 

 gravel does not extend southward beyond 

 the lake beds. In these high gravels there 

 occur- somewhat abundant large cobbles up 

 to 1 foot in diameter of quartz stained brown- 

 ish, and which are often rich in gold, one 

 bowlder sometimes yielding $20. The source 

 of this quartz is not known. It certainly does 

 not come from the high hills to the south. 

 Fig. 57 shows the general relations of the 

 high gravels at Idaho City. 



Another important bodj^of the high gravels 

 is found on the hill immediately east of Idaho 

 City. The gravel , which reaches a total depth 

 of 100 feet, forms a body about 2,000 feet long 

 and 1,000 feet wide. It rests throughout on 

 clayey and sandy lake beds, dipping gently 

 westward at an angle of 10. Seen from the 

 south side of the creek, the stratification 

 planes in the gravel appear to have a decided 

 dip westward, amounting to 4, or a little less 

 than the underlying rocks. The gravel rests 

 remarkably evenly on the. lake beds, with 

 but little sign of unconformity. The geolog- 

 ical section in fig. 57 illustrates the occur- 

 rence, while PI. XCV shows the gravel bank 

 and underlying lake bed in Plowman's claim. 

 A marked fluviatile stratification is often 



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