LINDGREN.] SHAW MOUNTAIN MINES. 707 



SHAW MOUNTAIN MINING DISTRICT. 



The veins in this district, apparently forming a continuation of 

 those on Fivemile Creek, were discovered in 1877. The veins are 

 located on the high ridge just north of the Idaho City stage road, 8 

 miles N. 80 E. from Boise, at elevations of about 5,000 feet. The 

 mines were prospected only on a small scale in 1896. The country 

 rock is normal granite, with a few smaller masses of granite-porphyry. 

 A strong sheeting of the granite is noted in many places between 

 Fivemile Creek and Shaw Mountain, the joints having the same 

 strike and dip as the veins. The Rising Sun vein is the most promi- 

 nent, and crops as a well-defined fissure vein of white quartz for 1 mile 

 near the summit of the ridge with a general east-west direction and 

 dip of 45 to 80 S. Four claims are located on it, from west to east, 

 as follows: Rising Sun, Paymaster, North Star, and Daisy. On the 

 first of these a 10-stamp mill was erected in 1879. It is developed by 

 several tunnels, the lowest 400 feet below the croppings and 500 feet 

 long. From the upper levels at least 500 tons were extracted, yield- 

 ing from $14 to $100 per ton; in the lowest tunnel heavy sulphide ore 

 was found which did not contain much free gold. From a sample of 

 this, collected from the dump and containing pyrite, arsenopyrite, 

 blende, and galena, an assay of 11 ounces of gold and 4 ounces of 

 silver was obtained, a total value of $230 per ton. The pay shoot is 

 stated to be 120 feet long, the width of the vein being not over 2 feet. 

 Some ore of similar character has also been extracted from the Pay- 

 master. The North Star, showing strong croppiugs of white quartz 

 on the summit of the sharp ridge, is said to contain five smaller shoots 

 of ore, and is opened by a tunnel 280 feet long, giving backs of 180 

 feet. A few hundred feet south of this vein, on two smaller parallel 

 veins, lie several claims, among which are the Kessler, Gold King, 

 and Levi. These veins, on which some good ore is said to have been 

 found, carry the same clean white quartz as the North Star; samples 

 of this barren-looking material gave $2 in gold and $0.49 in silver. 



Near the vein the granite has undergone the usual alteration due to 

 thermal waters. The brown mica (biotite) is converted to white mica 

 (muscovite), and! the feldspars are changed to a white opaque mass, 

 which is muscovite (sericite) in an extremely fine-grained aggregate. 

 Aggregates of coarse muscovite sometimes occur in the quartz from 

 this vicinity. 



MINING DISTRICTS OF WILLOW CREEK AND ROCK CREEK. 

 LOCATION AND TOPOGRAPHY. 



The Willow Creek district lies in Boise County, 18 miles distant 

 from Boise, in a direction N. 20 W., and is adjoined on the northeast 

 by the Rock Creek district, the two extending in an east-northeast 



