GEOLOGICAL SURVEY 
BULLETIN NO. 182 PL. X 
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.4. Finely crystalline ore from the Ridgway mine. Magnified 1 7 diameters : nicols crossed . large black 
areas, pyrite : small black areas, argentites, with a little sphalerite and galena: shaded areas, quartz 
11. Gangue of rich oie, Camp Bird mine Magnified 1 7 diameters ; nicols crossed ; black areas, fluonte ; 
shaded areas, quartz ; cross-hatched areas, calcite. 
VEIN-QUARTZ STRUCTURE. 
