First Report, 1908, with Accompanying Papers

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909. Excerpt: ... THE MONTEZUMA MINING DISTRICT OF SUMMIT COUNTY COLORADO By HORACE B. PATTON CONTENTS. INTRODUCTION 112 LOCATION AND HISTORY 112 FIELD WORK AND ACKNOWLEDGMENTS 112 TOPOGRAPHY 113 General 1.14 TRIANGULATION SURVEY 114 CLIMATE AND VEGETATION 117 CHAPTER I.--GENERAL GEOLOGY 119 INTRODUCTION 119 SCHISTOSE ROCKS 120 Idaho Springs Formation 120. The Hornblende-Gneiss Series 123 IGNEOUS ROCKS 125 GENERAL 125 PLUTONIC ROCKS 125 Montezuma Granite 125 Santa Fe Granite 126 Bear Mountain Granite 128 EFFUSIVE ROCKS 128 Granite Porphyry 128 Biotite Aplite 128 Other Aplites 130 Porphyries 130 Diabase 132 PEGMATITES 132 QUATERNARY GEOLOGY 133 General 133 Glacial Geology 134 Landslides 135 CHAPTER II.--ECONOMIC GEOLOGY 136 INTRODUCTION 136 THE VEIN SYSTEMS 137 CHARACTER OF THE VEINS 139 Nature of the Gangue 139 The Metal-Bearing Minerals 140 Origin and Geologic Position of the Veins 142 IRON ORE DEPOSITS 144 View across Snake River Valley, from the Silver Princess Mine, showing the lower wooded slope and the bare upper slope with the Sarsfteld Mine near the summit of Collier Mountain. INTRODUCTION. Location And History. The territory covered by this paper and by the accompanying topographic and geologic maps embraces an area of twentytwo miles, being a tract four miles from east to west and five and one-half miles from north to south, situated in greater part to the east and south of the town of Montezuma, Summit county, Colorado. This town lies only a few miles from the Continental Divide, near the head of the Snake river. As great activity has been manifested during the past year or two in this old and long-neglected mining camp, it was the purpose of the State Geological Survey to include as large an area as circumstances would allow in this investigation. It was found ...