64 BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



Creek. The black sand contains much garnet, also some monazite. 

 The gold occurs in streaks in the gravels and is fairly coarse. It 

 has a value of $15 an ounce, or is 0.710 to 0.720 fine. The pro- 

 gressive change in purity away from the source has been mentioned 

 on page 55. The lode deposits had produced $2,000,000 up to 1896. 

 The veins consist of white quartz carrying about 2^ per cent of 

 sulphides, mainly sphalerite, galena, pyrite, and arsenopyrite, 

 together with native gold, native silver, tetrahedrite tellurides, 

 argentite, and scheelite. The principal veins are the Little Giant, 

 Rescue, Goodenough, Charity, and Knott. The Goodenough vein 

 consists of from 2 to 20 cm. of solid quartz with well-defined walls. 

 The ore is high grade, showing native gold and sulphides including 

 zinc blende, pyrite, ruby silver, and probably tetrahedrite and 

 arsenopyrite. The sphalerite is rich in gold while the pyrite is 

 poor. 15 The Rescue vein forms a belt of crushed granite 15 to 50 

 cm. in width, schistose in places and inclosing small veinlets of 

 quartz containing foils of native gold. Scheelite accompanies gold 

 in the Charity vein. In 1916 the production from four lode mines 

 was $12,441 in gold. 



KOOTENAI COUNTY 



The Camas Cove or Tyson district had a production previous to 

 1905 of $500,000, entirely in placer gold. 



LATAH COUNTY 



Potlatch of Gold Creek district contains some gold placers. The 

 production in 1905, for example, was 225 ounces of gold. 



In the Moscow district some gold is produced from intermittent 

 placer operations. 



LEMHI COUNTY 



In the Blackbird district gold occurs as low grade replacements 

 of Algonkian quartzites and schists (Blackbird Copper-Gold Mining 

 Co.) and as oxidized quartz veins containing native gold in quartz 

 much stained by iron and manganese oxides (Musgrove group) . 



In the Carmen Creek district the Oro Cache, which is the principal 

 deposit, is a gold-quartz vein following a fault in quartzite. The 

 ore is mostly oxidized and is much stained by iron and manganese 

 oxides. The primary ore, where encountered, contains some pyrite, 

 chalcopyrite, galena, and sphalerite. The Carmen Creek mine is a 

 replacement deposit consisting of quartz lenses containing chalco- 

 pyrite, pyrite, and bornite. Much of the vein is oxidized and 

 native gold occurs with cerargyrite in cavities and along fractures 

 in the secondary ore. A specimen from Umpleby's collection shows 



'» Waldemar Lindgren, U. S. Qeol. Survey, 20th Ann. Rep., pt. 3, pp. 247-249, 1900. 



