THE MINERALS OF IDAHO 97 



The Texas Creek (Gilmore) district is also a lead-silver district 

 the primary ores of which consist of galena with some pyrite and 

 sphalerite. Unoxidized ore is rare, however, most of the lead being 

 in the form of carbonate. The Pittsburg-Idaho, Latest-out, and 

 Allie are the principal mines. The galena is for the most part in the 

 form of coarse cleavages forming residual cores in massive cerusite. 

 (Cat. No. 56528, U.S.N. M.) Specimens of coarse cleavable galena 

 from the Pittsburg-Idaho mine show very perfect twinning like that- 

 described in galena from the Minnie Moore mine, Blaine County. 



OWYHEE COUNTY 



In the rich silver ores of the Carson (War Eagle, Silver City, 

 Florida Mountain) district galena is rare except in the Trade Dollar 

 mine where it occurs as scattered grains in the richer ores. 



Ore from the Bergh mine, 11 miles north of De Lamar, contains 

 heavy sulphide masses consisting of galena in coarse cleavages inter- 

 grown with sphalerite and pyrite. Such ore is said to run $50 a 

 ton in gold. 



A specimen of ore from the Flint district, old Leviathan mine, 

 consists very largely of coarse cleavages of galena, in considerable 

 part oxidized to ashy grayanglesite which preserves, pseudomorphous, 

 the cubic structure of the original mineral. Masses of coarsely 

 crystalline feldspar occur in small amount included in the galena. 



The South Mountain district, now nearly abandoned, in former 

 years produced considerable amounts of argentiferous lead* ore con- 

 sisting of galena and its alteration products. Specimens in the 

 National Museum show the character of the ores to be as follows: 

 Rocksyfellow mine (Cat. No. 14822, U.S.N.M.), coarse granular 

 galena in masses with perfect undistorted cubic cleavage, altered in 

 part to earthy cerusite, anglesite, and bindheimite; Washington 

 mine. Coarse granular argentiferous galena with massive cerusite in 

 iron-stained rock; Yreka mine (Cat. No. 65663, U.S.N.M.), granular 

 galena with earthy oxidation products; Monkey mine (Cat. No. 14539, 

 U.S.N.M.), coarse granular galena altering to bindheimite and linarite. 

 Primary ore from the Golconda mine (Cat. No. 65677, U.S.N. M.) is 

 moderately coarse granular galena with pyrite and partly oxidized 

 material shows coarsely granular galena partly altered to white glassy 

 cerusite with sparingly developed minium and bindheimite. The 

 Golconda ore occurs in crystalline limestone and is apparently of 

 contact metamorphic origin, being associated with garnet, pyroxene* 

 and ilvaite. Much of the unaltered ore from this mine is refractory, 

 being intimately mixed with pyrite arsenopyrite, sphalerite, etc. 

 54347— 26t 8 



