510 
INDEX 
Page 
Old Gold mine, view of. 350 
workings of. 356 
Old Gold Mining Company, mines of. 355 
Old Hickory claim, location of. 349 
Oligoclase, description of. 127 
occurrence of. 44,83,114.193,194 
Oliver shaft, location of. 4S4 
Olivine, description of. 127 
occurrence of. 53-54,55,64,92,93,95,103,114 
Olivine syenite, composition of. 102 
description of. 53 
occurrence of. 53 
petrology of. 53-55,102 
See also Syenite. 
Opal, description of. 123 
occurrence of. 4,100,114,169,174,176,178,402 
Ophelia tunnel, description of. 291 
dike in. 93,324 
drainage by. 9,235,242,244 
gas in. 254,256,269 
location of. 291,322 
minerals in. 124,125,126,128,174,175,177,183 
ore from, photomicrograph of. 180 
rocks in. 26,85 
temperatures in. 270 
yeins in, character of. 163,174,182 
Ophir Mining and Milling Company, mine of. 484,495 
Ore bodies, description of, terms used in, diagram 
showing. 206 
occurrence of, method of, plan showing. 212 
See also Ore deposits; Lode fissures; Ore shoots; 
Veins; Ores; Gold deposits; etc. 
Ore deposits, conclusions on. 8-9 
depth of. 32 
distribution of. 5,140,146,147 
enrichment of. 203-204 
genesis of. 8-9,217-231 
inconspicuousness of. 134,154 
metasomatism of. 184-185,188-196 
mining and milling of. 4-5,135-142 
technology of. 5,140-142 
oxidation of. 196-204 
production of. 4,134-135 
See also Ores; Ore bodies; Ore shoots; Veins; Gold 
deposits; etc. 
Orehouse tunnel, location of. 315 
Ores, analyses of. 172,173 
character of. 6,7,169-170 
chlorination of. 139 
composition of. 170-173 
cyanidation of. 139 
depth and relations of. 8 
description of. 137,169-183 
milling of. 138-139 
mineralogy of. 173-176 
occurrence of. 6-7 
origin of.217-231 
oxidation of. 169-170 
photomicrographs of. 180,186 
sorting of. 136-137 
smelting of. 4,139 
structure of. 176-182 
tenor of.... 6-7,8.170-173,223 
treatment of, cost of. 145-146 
value of.*. 170-173 
varieties of. 182-183 
See also particular mines; Ore deposits; Gold 
deposits; etc. 
Page 
Ore shoots, country rock and, relations of. 208-209 
depth and, relations of. 207-208,214-216 
description of. 205-216 
synopsis of. 8 
terms used in, diagram showing. 206 
intersections of veins and, relations of. 209-213 
pitch of. 206 
shape of. 205-208 
plate showing. 206 
surface and, relations of. 207-208 
veins and, intersections of. 209-213 
vertical range of, plate showing. 206 
Ore vein, character of. 287 
Orizaba claims, location of. 349 
Orpha May mine, dikes in. 381 
gas in. 261,380 
location of. 5,149 
minerals in. 124,176 
ore bodies in. 212 
production of. 380 
vein of. 380,382 
water level in.:. 240,244 
change in, figure showing. 242 
workings in. 380,383 
Orpha May vein, location and description of. 380.382 
Orpha Nell claim, location of. 478 
Orphan shaft, character of. 396 
Orthoclase, description of. 127 
occurrence of. 44 
46,47,49,51-52,53,56,67,68,72,73,81.83,85 
86,92,95,100,103,114,174,183,188,194,443 
Osmotic hypothesis, G. F. Becker on. 229 
Oxidation, alteration due to. 7,184,196-204 
depth of.7,196 
effects of. 203-204 
processes of. 199-203 
structure resulting from. 199 
water level and, relations of. 198-199 
See also particular mines, localities, etc.; Metaso¬ 
matism; Hydrometamorphism; Water; 
Alteration. 
Oxides, etc., description of. 122-129 
P. 
Palache, Charles, on sylvanite. 116,360 
Paragenesis of minerals, discussion of. 175-177 
Parallel vein, location and description of. 371,489 
Parker & Head vein, location of. 360 
Par Value vein, character of. 476 
location of. 314 
Pay Rock claim, location and description of. 279 
Pearce, Richard, on oxidation. 201,203,204 
on sylvanite. 116 
Pearl mine, location of. 406,478 
Peggy mine, description of. 330 
Peggy vein, character of.211,330 
Pegmatite, description and petrology of. 48 
Penrose, R. A. F., on Anna Lee chimney. . 447-448 
on discovery of gold. 130 
on granite ore. 193 
on kaolin. 128 
on metasomatism. 195-196 
on Orpha May vein. 382 
on placers. 152 
onpyrite. 170 
on Raven dike. 336,338 
work of.1,4,11,147,171 
