704 IDAHO MINING DISTRICTS. 



GEOLOGY. 



The geological structure of the Lucky Peak ridge is very simple. 

 It consists nearly entirely of the normal granite of the Boise Moun- 

 tains. A number of dikes vary the monotony, but consist almost 

 exclusively of light-colored granite-porphyry, which have in general 

 a northwesterly trend and a width occasionally attaining 100 feet, but 

 usually much less. Placer deposits hardly found place to accumulate 

 in the steep gulches and cut no figure in the production of the camp, 



MINERAL, DEPOSITS. 



A number of gold-quartz veins are found in the Black Hornet dis- 

 trict; and they are not confined to the district. Scattered small veins 

 occur in the granite between this region and the Neal mining district, 

 9 miles to the southeast. West and southwest from Lucky Peak scat- 

 tered prospects are also found; likewise to the north and northwest, 

 connecting in the latter two directions with the Shaw Mountain and 

 the Boise districts. The northern part, or the Deer Creek district, 

 has been known for a long time. On the Montana claim an arrastre 

 was built and worked many years ago by Mr. Plowman, of Idaho City. 

 But the southern and lately most productive part, near the Black 

 Hornet mine, has been known only during the last few years. 



The production has been confined almost entirely to ore shipped to 

 smelting works from the Black Hornet or Ironsides mine. During 

 1895 and 1896, 200 carloads are said to have been shipped, averaging 

 $40 per ton, which would give a total product for the camp of about 

 $24,000; the total production is probably $30,000. 



The veins in this vicinity differ markedly in direction and dip from 

 those at other camps on the range. Instead of a strike ranging from 

 east-west to northeast-southwest, we here find veins striking north- 

 south or northwest-southeast, and with a dip of 45 to 50 to the west. 

 Though base ores prevail, some of the veins carry a notable percent- 

 age of free gold. 



The more prominent claims begin at the Viola mine and extend for 

 2^ miles northward. South of the Viola are a number of prospects, 

 some of which, such as the Fraud and the Ruby, are reputed to be 

 promising. 



The Black Hornet vein extends through the Viola and Ironsides 

 claims, but can hardly be traced any farther. Having at first a direc- 

 tion of N". 20 W., it changes in the Ironsides claim to N. 40 W., the 

 dip being to the southwest at 50. The vein crops along a ridge lead- 

 ing up to Lucky Peak, and a sharply cut ravine several hundred feet 

 deep offered excellent place for tunnels to tap the vein. The Viola 

 shows on the crumbling granite on the surface as a strong vein of 

 white quartz. It is developed by a crosscut tunnel 200 feet long 



