ransome.1 OKE MINERALS. 85 
In the Sunnyside Extension mine a sulphobismuthite of lead and 
silver, showing no distinct crystal form, occurs intimately associated 
with molybdenite and free gold in an ore containing quartz, barite, 
sphalerite, pyrite, and galena. In the Mastodon, which adjoins the 
Sunnyside Extension on the north, an argentiferous sulphobismuthite 
of lead showing indistinct prismatic crystallization occurs so finely 
disseminated in quartz as to give the latter a dark clouded appearance. 
In the Custer claim on California Mountain an argentiferous lead, 
sulphobismuthite, forms the richest ore, and similar bismuthiferous 
compounds occur in the ores of the Sound Democrat and Silver Queen 
mines in Placer Gulch. 
A lead-copper sulphobismuthite, probably argentiferous, occurs in 
small, ragged prisms, frequently forming star-like radial clusters, in 
quartz with pyrite at the Uncompahgre Chief, near Mineral Point. 
At the Silver Bell mine, between Ironton and Red Mountain, the 
richest ore was a massive argentiferous lead sulphobismuthite carry- 
ing up to 1,000 ounces of silver per ton. Massive argentiferous lead 
sulphobismuthites, of probably more than one species (one of them 
cupriferous), occurred in the Genesee-Vanderbilt ores, intimatety asso- 
ciated with barite and pyrite. A massive lead sulphobismuthite (with, 
perhaps, a little copper) has been found in the Silver Queen mine on 
Bear Creek. In the Neigold group of claims on Galena Mountain a 
lead sulphobismuthite, carrying a little silver and perhaps some cop- 
per, occurs as small indistinct prisms and specks in quartz with pyrite, 
specularite, and bismuthite. Lastly, it is known that rich bismuth- 
iferous ores, probably argentiferous lead sulphobismuthites, were for- 
merly mined in the Old Lout and Poughkeepsie mines, and are 
probably present in varying amounts in most of the lodes of Pough- 
keepsie Gulch. 
Tellurides. — The occurrence of tellurides of gold or silver has been 
noted at only four localities within the quadrangle, and at each of 
these in small amounts only. In some of the rich ore of the Camp 
Bird mine a little tellurium, probably occurring as a telluride, has 
been detected chemically by Dr. Hillebrand, although no tellurium 
mineral has been recognized. In the Barstow mine small amounts of 
an unknown telluride are intimately associated with an argentiferous 
lead sulphobismuthite and pyrite. Its presence can be detected only 
by chemical means. At the Silver Ledge mine a small amount of a 
telluride resembling calaverite was found, with free gold in a single 
small pocket. At the Magnet mine telluride of silver, probably hess- 
ite, occurs, intimately associated with argentiferous galena and a little 
free gold in a quartz gangue. 
Gold. — Isometric, but rarely showing crystal form. Usually in 
irregular hackly particles. Gold yellow. Hardness, 2.5-3. Very 
malleable and ductile. Specific gravity, 15.6-19.3. 
Eree or native gold occurs in arborescent sheets in quartz and 
rhodonite in the Golden Fleece vein (see p. 183). In the Sunnyside 
