72 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 182. 
and other lodes in Poughkeepsie Gulch. In practically all the stocks 
of the Red Mountain district barite was found in close association 
with the argentiferous copper ores. Thus in the Guston and Yankee 
Girl the bornite or chalcocite often incloses numerous isolated crys- 
tals of translucent barite, and it is to be found on nearly every mine 
dump in this vicinity. It also occurs in the Zuiii mine, on Anvil 
Mountain, embedded in kaolinite, and with zunyite in guitermanitc. 
Where occurring in lodes, the barite is very commonly associated with 
gray copper (tetrahedrite). In the Mastodon claim, on the Sunny- 
side lode, barite forms with quartz a finely crystalline aggregate 
which constitutes the gangue of a highly argentiferous lead sulpho- 
bismuthite. 
( 'alcite. — CaC0 3 . Rhombohedral. Commonly massive or in rhom- 
bohedrons, scalenohedrons, or prisms. Cleaves perfectly in three 
directions, affording rhombohedrons. White. Transparent to opaque. 
Hardness, 3. Specific gravity, 2.71. Effervesces freely with cold 
dilute acid. 
Calcite is less abundant than barite in the productive lodes, but is 
nearly always present in small amount, particularly in small vugs and 
in minute veinlets cutting the ore. As the principal filling of miner- 
alized veins it was noted at the Oneida, a prospect at the head of 
American Basin, where it carries sphalerite with a little pyrite, chal- 
copyrite, and galena, and at the Yellow Jacket claim on Bear Creek, 
on the northern edge of the quadrangle, where also it contains abun- 
dant sphalerite. In both cases the ore is too poor to work. As an 
important gangue constituent it was noted in some of the copper- 
bearing lodes north of Hanson Creeks At the Osceola claim in Cun- 
ningham Gulch it occurs pseudomorphous after tremolite. In the 
Camp Bird mine it is fairly abundant, filling vugs and spaces in the 
quartz left by comb structure. As a microscopic constituent calcite 
is found almost invariably in the wall rocks near the lodes, except 
where the rock has been silicified, in small amount with rhodonite and 
rhodochrosite in the so-called "pink spar" (chiefly rhodonite) of the 
Sunnyside and other mines, and with fluorite and quartz in a pale- 
green ciyptocrystalline aggregate accompanying and forming part of 
the rich streak in the Camp Bird lode. 
As limestone, impure massive calcite occurs at several points in the 
quadrangle, and on the east side of Sultan Mountain and at the 
Saratoga mine in Ironton Park is directly associated with deposits 
of ore. 
Dolomite. — CaMg(C0 3 ) 2 . Rhombohedral. Usually massive or in 
curved rhombohedra. Cleavage like calcite. White to brownish. 
Milk}- to opaque. Hardness, 3.5. Specific gravity, 2.88. Effervesces 
with cold dilute acid only when finely powdered. 
This mineral is not abundant or important in connection with the 
ore deposits, but occurs as a microscopic constituent with rhodonite 
and rhodochrosite. 
