ILLUSTRATIONS. 



PLATE I. Topographic map of Tonopah mining district:. 



II. A, B, View from near eastern corner of area mapped on PI. I, looking southwest; 

 C, D, Tonopah and surroundings, looking west from Mount Oddie; E, F, 

 Panorama, looking south from Butler Mountain 24 



III. Map of mining claims, adapted from map of Booker and Bradford, Tonopah 26 



IV. Heller Butte '.. . 38 



V. A, B, Butler Mountain; C, D, View, looking northwest from a point between Rushton 



Hill and Golden Mountain; E, F, View north from Butler Mountain 44 



VI. A, Brougher Mountain and Tonopah, seen from Mizpah Hill; B, Butler Mountain 



from east base, showing columnar dacite above and stratified Siebert tuffs below... 46 

 VII. Diagram showing relative displacement of fault blocks and their relation to the dacite 



necks 48 



VIII. Diagram showing relative provinces occupied by the Brougher dacite and the rhyolite 



necks, and the relation of the fault lines to the former 50 



IX. A, Siebert Mountain from the northeast; B, Mount Oddie from the northwest 52 



X. Face of Siebert Mountain from the southeast 54 



XI. Geologic map of Tonopah mining district 56 



XII. Diagrammatic map showing two parallel zigzag south-facing scarps 76 



XIII. Fragment of Montana vein, actual size, showing crustification 84 



XIV. Map showing the chief veins of Ararat Mountain and their restriction to the white 



rhyolite plug 102 



XV. A, Recent basaltic cone near Silver Peak; B, East front of Quinn Canyon Range, 



showing wash apron typical of the region 112 



XVI. Geologic map of productive portion of the Tonopah mining district, showing out- 

 cropping veins and regions developed by underground workings 114 



XVII. Outcropping veins of Mizpah Hill 116 



XVIII. Siebert shaft, Tonopah Mining Company 118 



XIX. Horizontal plan of veins as developed in midsummer of 1903 on Mizpah Hill, on 



the plane of the 300-foot level of the Mizpah 120 



XX. Cross sections showing structure of Mizpah vein . 122 



XXI. Horizontal plan of veins and faults in Wandering Boy and Fraction 300-foot 

 levels, together with projected position of the main Fraction and Wandering 



Boy faults at this level 162 



XXII. Horizontal plan of veins and faults in the Montana Tonopah 512-foot level 172 



XXIII. A, B, C, Pyrite and siderite in Tonopah andesite; D, E, F, Adularia in early 



andesite and veins 208 



XXIV. Diagrams to show the changes in composition brought about by the alteration of 



the earlier andesite 218 



15 



