LIST OF ILLUSTRATIONS 



Page, 

 Plate I. — Weathered augite-andesite ou divide lietweeu Mimiit Rose and Mount Kate; Moiuit 



Davidson and Monnt Butler in the distance Frimtispiece. 



II. — Single minerals, as seen under the microscope follows 1')! 



111.— Ditto ' do... IM 



IV. — Rock sections, as seen under the microscope do. . . 151 



v.— Ditto do... 101 



VI. — Bullion Ravine, looking east (diorite); Mount Kate in the middle distance faces 192 



VII. — East flank of Mount Rose (later horablende-andesite) do. 204 



Fig. 1. — Area of extreme decomposition 73 



•>. — Orientation of slides 145 



:i. — System of equal, vertical, movable sheets 160 



4. — Calculated and observed curves 167 



5. — Logarithmic curve referred to rectangular coordinates 168 



6. — Logarithmic curve referred to inclined coordinates 171 



7. — Inclination of a faulted surface 172 



8. — Double fault^curve 173 



9. — Fault accompanied by a strain 175 



10. — Contour map of a faulted surface 177 



U. — Rise of the hanging vrall 179 



12. — Ideal section across the Virginia Range 243 



13. — Combination Shaft and Yellow Jacket temperatures 249 



14. — Yellow Jacket Shaft aud Fonuan Shaft temperatures 251 



15. — Formau Shaft temperatures 253 



16. — Rose Bridge Colliery and Formau Shaft temperatures 255 



17. — Spereuberg Boring, Formau Shaft, and Rose Bridge Colliery temperatures 257 



18. — Sutro Tunnel temperatures 259 



19. — Boiler nsed in kaolinization experiments 292 



20. — Disposition of apparatus 295 



21. — Section of key 296 



22. — Ideal line of electrical survey 316 



23. — Longitudinal section of terminal -- 32.') 



24. — Terminal in position 326 



25. — Mode of suspending wire 327 



26. — Vertical section through Richmond ore bodies 331 



27. — Plan of the 400 and 500-foot levels, Richmond mine 333 



28. — Earth-potential and distauce, Richmond mine, 400 and ."jOO-foot levels 343 



29.— Plan of the 600-foot level, Richmond mine 344 



30. — Earth-potential and distance, Richmond mine, 600-foot level 349 



:U. — Disposition of apparatus for measuring earth-potential 353 



32. — Earth-potential and distance, Richmond mine, 600-foot level (later results) 354 



33. — Potential of iuteniieiliate ])ciints 362 



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