664 IDAHO MINING DISTRICTS. 



visible. The gravel is medium coarse and is made up chiefly of gran- 

 itic bowlders with occasional pebbles of quartz. By tracing this area 

 around, it is found that the bed rock rises gently, being at the 

 eastern end at least 200 feet above the creek. At the western end the 

 exposures are not so good, as tailings and bench gravels lie up against 

 the higher gravels and the underlying beds are not here visible. The 

 gravel on East Hill, as this area is called, has been worked by the 

 hydraulic process for a number of years, and the claim is reported 

 to have produced from $10,000 to $20,000 a year. The largest part of 

 the gold is found resting on the soft bed rock. The upper part of the 

 gravel also contains some gold, but probably not more than about 5 

 cents per cubic yard. The gold is fairly coarse, and has a value of 

 $16.50 an ounce before melting. On the surface of the gravel the gold 

 appears to be more abundant, which is probably caused by a gradual 

 concentration by atmospheric agencies. 



Another large body of gravel is that known as Gold Hill (fig. 57), 

 occupying about 160 acres and situated on the point between the creek 

 and Bear Gulch. The top of this gravel body is 350 feet above Idaho 

 City, and its greatest depth is probably not less than 200 feet. Along 

 Elk Creek and Bear Gulch the gravel rests on the same soft lake beds 

 which crop out on East Hill. Toward the southwest tailings lie up 

 against it. On the northeast side, on the other hand, the gravel rests 

 directly on granite bed rock. Here also the dip of the gravel beds is 

 about 4, while that of the lake beds is 10 W. Good exposures, made 

 by hydraulic mining, are seen on the southwest side. One-fourth 

 mile north of Idaho City the surface of the soft lake beds lies 20 feet 

 above the creek. Above the lake beds lies 15 feet of coarse heavy 

 gravel with many subangular fragments. Above this is 10 feet of 

 sand with clay streaks, sometimes a little coaly, and somewhat 

 resembling the lake beds. Capping this sand is ordinary well- washed 

 gravel. Here, as in the other gravel bodies, the largest pay was 

 found on the surface of the bed rock that is, on the surface of the 

 lake beds and this rich bottom stratum has been mined by the drift- 

 ing process both on the southeast and our the southwest side. A large 

 body of gravel here remains, which can be worked by the hydraulic 

 process, although it is probably of low grade. Owing to some diffi- 

 culty in procuring water, the claims on this hill have not yet been 

 extensively worked. 



On the ridges above these deposits no other gravel masses have been 

 found, but a small body rests on a sidehill to the east of Elk Creek, 3 

 miles northeast of Idaho City, at an elevation of about 200 feet above 

 the creek. On the western side of Elk Creek, opposite Idaho City, 

 small patches of gravel are occasionally found 200 feet above the 

 creek level, and scattered pebbles occur in many places at about this 

 elevation. Still another body of high gravel is that found on the 

 point between Granite Creek and Moore Creek, east of Idaho City. 



