4 CONTEXTS. 
Page. 
Economic geology 42 
History of mining development 42 
Economic conditions 43 
General character of the ore deposits— 44 
Post-Jurassic and pre-Tertiary deposits ., 44 
Deposits in granite 44 
Deposits in Palezoic sedimentary rocks, predominantly lime- 
stone ^4 
Tertiary deposits 46 
Gold deposits in silicified monzonite porphyry and related 
rocks 46 
Deposits in rhyolite 46 
Aids to prospecting 49 
I descriptive geology 50 
Region about Goldfield 50 
Lone Mountain foothills 51 
Topography and geography 51 
General geology 51 
Sedimentary rocks 51 
Cambrian 51 
Older alluvium 52 
Igneous rocks 52 
Granite 52 
Diorite and diorite porphyry 53 
Structure 54 
Economic geology 54 
Northeastern extension of the Silver Peak Range • 55 
Topography and geography 55 
General geology 56 
Sedimentary rocks 56 
Cambrian l 56 
Siebert lake beds 57 
Travertine 58 
Igneous rocks 58 
Post-Jurassic granite, granite porphyry, and quartz- 
monzonite porphyry 58 
White quartz-monzonite porphyry 6<) 
Diorite porphyry 60 
Andesite 61 
Rhyolites and dacites 61 
Later rhyolite 62 
Basalt 62 
Structure 62 
Economic geology 63 
Montezuma district 63 
Lida 64 
Other mineralized areas 65 
Lime (55 
Lida-Goldfield Valley 65 
Mount Jackson and the hills to the northeast 66 
Topography and geogra phy ca\ 
