WASHINGTON GEOLOGICAL SURVEY HENRY LANDES, Sta.te Geologist BULLETIN No. 1 GEOLOGY AND ORE DEPOSITS OF REPrr.BLIC MINING DISTRICT By JOSEPH B. fillPLEBY OLYMPIA, WASB. : E. L . BOARDMAN, PUBLIC PRINTE.R. 1910. BOARD OF GEOLOGICAL SURVEY GovERNOR M. E. li.AY, Chair-mani STATE TREASURER. J. G. LEWIS, S ecretary PRESIDENT T. F. KANE PRESIDENT E. A. BRYAN HENRY LANDES, State Geologist SotoN SHEDD, Assista;nt State Geologist CONTENTS Page ILLUSTRATIONS . • • • . • • • . • • • • • • • • • • . • • • • • • . • • . • • . • • . • . • • . • . • • • 5 LETTER OF TBANSMJTTAL • . • • . • . • . • • • • • • • • • • • . • • • . • . • • • • • 6 INTRODUCTION . 7 Location . ... 7 Field work and acknowledgments. 7 Previous work ............................. ·. 8 General remarks . 8 CHAPTER I-P:HYSIOORAPRY • . • • . • • • . • • . • . • • . • • • 9 Topography . 9 General character . 9 Drainage . ... 9 Principal features . 9 Changes in drainage . 10 Glacial features . 10 Eocene peneplaln . 11 Correlation . 12 CUmate . ... 14 CHAPTER II-GENEBAL GEOLOGY • . • . • . • . • . • . • • 15 General statement . 15 Description of rock formations............................... 16 Paleozoic series . 16 Distribution . 16 Cbaracterlstlcs . 16 Age . ... .. 17 Granodiorites . 17 Distribution . .. 17 Characteristics . 18 Age . ... 18 Tertiary formations . 19 Relation to older formations. 19 Daclte flow conglomerate. 20 Distribution . 20 Characteristics . 21 Age • • • . • . • . • . • • •. • . • . • . • • . • • . •.• . • • . • . 22 Andesite flows and lake beds............................ 23 Earlier andesite flow breccia. 23 Distribution . 23 Cbaracteristics . 23 Age . ... 24 Lake beds . 24 Distribution_ . 24 Characteristics . 24 Age . • . • • . • • . • • . • • .•. • . 24 4 Table of Contents CHAPTER II-GENERAL GEOLOGY (Continued.): Description of rock formations­ Tertiary formations- Andesite flows and lake beds ( Oontinued.) : Page Trachyte flow . 25 Later andesite flows. 25 Distribution . 25 Characteristics . 26 Latite porphyry . 27 Distribution . 27 Characteristics . 27 Basalt flow . 28 Relations . 28 Characteristics . 28 Quaternary history . 28 Glaciation . 29 The drift . 29 Stream erosion . 30 CHAPTER III-EooNOMIO GEOLOGY . • . • . • . • . 32 History of mining development. 32 Production . 34 Metallurgy . 34 The veins . 37 Distribution . .. 37 General characteristics . 37 Minerals of the ore. 39 Geologic relations of the veins. 41 Genesis of the ore. ... 41 Effect of solutions on wall rock.............................. 42 Placer mining . 43 CHAPTER IV-DETAILED DESOBXPTION Oli' PRINCIPAL MINES........ 44 New Republic mine.......................................... 44 Location . 44 History and production...................... .............. 44 Development . 45 Wall rock ................................ , . 45 The vein . .. 46 The ore . 48 Ben Hur mine............................................... 50 Morning Glory mine. 52 South Republic mine......................................... 52 Quilp mine . 53 Surprise mine . 54 Black Tall mine. 56 Lone Pine mine.......... ......................... .......... 59 San Pou mine. ............... ................... ........... 62 Mountain Lion mine. 63 Tom Thumb mine.... ......................... ............... 64 Elcaliph . 65 ILLUSTRATIONS Plate. Facing Page I. Town of Republic. 8 II. Black Tail and Lone Pine mines.......................... 8 III. Geologic map o.f Republic mining district................. 16 IV. Dacite fl.ow conglomerate; A, Usual texture; B, Coarse phase 24 V. Interstratlflcation of shale with daclte breccia. 24 VI. Quartz breccla from Lone Pine mine...................... 32 VII. Andeslte fl.ow breccla.. ..