XIV GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



CHAPTER III. 



Page. 



ROCK FORMATIONS 45 



Sedimentary rocks 45 



Archeau format ious 45 



Granite >. 4g 



Gneiss 48 



Amphibolite 50 



Relative age 51 



Paleozoic formations 53 



('aml>ri:tu 58 



Lower Quartzite 58 



iSiluriiiii tjO 



White Limestone 60 



Parting Quartzite (il 



Corresponding beds in Colorado Range 62 



Carboniferous 63 



Blue or ore-beating limestone 63 



Its composition 04 



Weber Shali-s 67 



Weber Grits 68 



Upper Coal Measures . 69 



Mesozoic formations 70 



Quaternary formations 71 



Glacial or Lake beds 71 



Recent or post-glacial 72 



Distribution of sedimentary formations 72 



Eruptive or igneous rocks 74 



Secondary cruptives 74 



Mount Zion Porphyry White Porphyry 7(i 



Lincolu Porphyry 78 



Ci-.-iy Porphyry 80 



Sacramento Porphyry 81 



Pyritiferous Porphyry 82 



Mosquito Porphyry Green Porphyry Silverheels Porphyry 83 



Diorite 84 



Porphyrite 85 



Tertiary cruptives 86 



Rhyolite 87 



Trachyte Andesite 83 



CHAPTER IV. 



DESCRIPTIVE GEOLOGY OF THE MOSQUITO RANGE 90 



Introductory 90 



Surface features 91 



Glacial formations 92 



Post-Glacial formations Archeau exposures !3 



Northeastern division 94* 



Platte amphitheater 94 



Quandary Peak 96 



Hoosier pass ridge 100 



Silverheels Massive 104 



Lincoln Massive 107 



Cameron amphitheater Ill 



