30 
INDEX. 
Page. 
Mineralization and hot-spring action at 
Tonopah, resume of 17-18 
Miriam shaft, rock in which located 14 
Mizpah group of veins, period of formation, 
importance and character of 1C 
Mizpah Hill, main groups of veins 19 
outcrop of early andsite on 12 
Mizpah Hill veins, development of 19 
Mizpah mine, shipments from 8 
Mizpah vein, characteristics of branches of. 20 
horizontal plan of portion of, at 250- foot 
level 18 
limit of oxidized zone in 23 
oxidation of ore in 24, 25 
Molly shaft, rock in which located 15 
Montana Tonopah chief vein, brecciation 
and subsequent cementation 23 
Montana Tonopah group of veins, charac- 
teristics of 20 
period of formation, importance, and 
character of 1G 
Montana Tonopah mine, shipments from to 
July 15, 1903 8 
Montana Tonopah shaft in later andesite. . 13 
Mount. Gee next word of name. 
New York Tonopah shaft, rock in which 
located 14 
North Star mine, early andesite rock in 13 
North Star tunnel, in white rhyolite 14 
Oddie, T. L., connection of, with discovery 
and development of the district 7 
information furnished by 8 
Oddie Hill, lava of 14 
Oddie Mountain, rhyolite of, compared 
with later intrusive dacite 15 
some misconceptions concerning 27 
Ohio Tonopah mine, early andesite rock 
in 13,14,19 
rhyolite in vicinity of 14 
Ordonez, Ezequiel, reference to 28 
Ore, weight and value of, shipped to April 
1, 1903 8 
Ore shoots, veins where recognized 25 
Ores, occurrence of, in the veins 21-25 
proportion of gold to silver values in . . 9 
secondary sulphides, characteristics of. 23 
Ores, oxidized, limits and characteristics of. 23-25 
some mineral constituents of 16 
Ores, primary characteristics of 23 
microscopic examination of 23 
Ores, sulphide, of veins formed subsequent 
to early andesite intrusion 16 
Pachuca district, Mexico, comparison of 
veins of 28 
Pegmatite in volcanic breccias 9 
Polybasite, occurrence of 16, 23 
Population of Tonopah camp, estimate of.. 7 
Prospecting, localities and rocks not very 
favorable for 26, 27 
most favorable rocks for, above the 
early andesite 25 
probable favorable location for 25 
region worthy of 26 
suggestions as to economical methods 
of 27,28 
Pyrite, occurrence of 16, 17, 23 
Page. 
Rescue shaft, in white rhyolite 14 
Rhyolite, methods of distinguishing from 
andesite 14 
Rhyolite eruptions and later intrusions 10, 11 
Rhyolites, distribution and characteristics 
of 14 
Rocks of the region, description of 12-15 
Ruby silver, occurrence of 16, 23 
Rushton Hill, lava of 14 
Siderite, occurrence of 17 
Siebert Mountan, basin partly inclosed by. 14 
reference to 10, 11, 26 
Silver, proportion of, to gold by weight in 
veins formed subsequent to early 
andesite intrusion 16 
proportion of, to gold in the ores 9 
Silver bromide, occasional occurrence of . . 16 
Silver chloride, occurrence of 16 
Silvertop shaft, rock in which located 14 
Silvertop workings, unoxidized rock near 
surface in 24 
Stephanite, primary, occurrence of 16, 23 
Stone Cabin shaft, limit of oxidized ore in. 24 
Sulphides, alterations of 24 
Tonopah, altitude of 9 
location of 7 
Tonopah City shaft, rock in which located. 15 
Tonopah Mining Company, development 
work by 7 
Topography of the region 9 
Transportation facilities to the camp 7 
Tuffs and volcanics of the district 9 
Valencianite, reference to 16, 23 
Valley View, group of veins, characteristics 
of 20 
detailed vertical section at surface of 
one of „ 22 
limit of oxidized ore in 24 
period of formation, importance and 
character of 16 
Value of ore shipped to April 1, 1903 8 
Values in gold and silver of veins of rhyolite 
period at Gold Mountain 17 
in precious metals at contacts of large 
dacite necks 17 
in the ores, proportion of gold to silver. 9 
Values, comparative, in gold and silver in 
veins subsequent to later rhyolite 
intrusions 17 
Vein, crustified, example of, in Montana 
Tonopah workings 22 
Vein deposition, evidence showing age of . 15 
Vein groups of early andesite mineraliza- 
tion 18-21 
"Vein robbers," use of the term 21 
Veins, bearing of direction of trends on 
values 21 
difficulty of ascertaining age of 18 
earliest and most important class of, 
rock where found 17 
enrichment and impoverishment of 20, 21 
exceptions to replacement type 22 
formation of, by replacement of andesite 21 
gangue material of those formed subse- 
quent to early andesite and early 
rhyolite intrusions 16 
