706 IDAHO MINING DISTRICTS. 



Three miles east of Boise, on the north side of the stage road in 

 Cottonwood Creek, are several claims, Morning Star, Last Chance, 

 and First Chance, located on a narrow vein striking northeast-south- 

 west and dipping south, the developments consisting only of two tun- 

 nels 100 feet long. High assay values in silver have been found on 

 the first claim, while the others chiefly contain gold. One and a half 

 miles further east, just north of the road, is another claim said to 

 have yielded some rich decomposed silver ore. 



On Picketpin Gulch, 5 miles east of Boise, are the Golden Star loca- 

 tion and a great number of other claims. The Golden Star claim is 

 said to cover two parallel veins and a cross vein, but the openings do 

 not show the character of the deposit very clearly in the decomposed 

 granite. 



An arrastre wa built on this claim many years ago and the soft 

 decomposed ore treated in it is said to have yielded $33 per ton. A 

 small mill was erected a few years ago, but it did not run long. Man} 7 

 of the veins in this vicinity show no quartz, but only a streak of ther- 

 mal alteration on each side of a fault plane. Mr. Eldridge 1 mentions 

 at this same locality "several narrow dikes of lamprophyre, trending 

 N. 50 to 70 W. and dipping 45 to 80 SW. A vein of quartz lies 

 between two of these." The dark-green, fine-grained dike rock from 

 this locality is panidiomorphic granular, and consists chiefly of brown 

 hornblende and orthoclase with some soda-lime feldspar. It appears 

 to be a syenitic lamprophyre connected with the vogesites. In the 

 lower part of Fivemile Creek many strong quartz veins appear, all of 

 them having an east-west direction and a southerly dip of from 50 

 to 60. The Scorpion is a well-defined vein showing 2 to 3 feet of 

 solid quartz between granite walls. A tunnel 100 feet long has been 

 driven in this vein in the western side of the creek. The quartz, 

 which contains scattered iron pyrite and arsenopyrite, is said to assay 

 up to $8 per ton. A dike of fine-grained, dark-green minette, a 

 species of syenitic lamprophyre, was cut in the lower tunnel and 

 appears to lie nearly parallel to the vein. The dike is considerably 

 altered, filled with calcite, sericite (white mica), and pyrite, and car- 

 ries about $1.65 in gold. Claims adjoining on the same vein are the 

 Elevator and Hattie, while parallel to it and adjoining northward 

 are the Badger and Free Gold. Parallel veins also lie on both sides 

 of the Idaho City stage road at the mouth of Fivemile Creek, and 

 scattered prospects extend eastward to Shaw Mountain district. The 

 Tornado and Blizzard claims are situated 1 mile northeast of the Scor- 

 pion, and carry heavy sulphide ore, zinc blende, galena, and pyrite, 

 having high assay value but containing no free gold. 



1 Sixteenth Ann. Bept, U. S. Geol. Survey, Part II, 1895, p. 335. 



