Economic Geology, Volume 1

altered amount andesite appear applied geology basin beds bornite Bull calcite California carbonate cent chalcocite chalcopyrite chemical chert cinnabar clay coal conglomerate contain copper Creek Cretaceous crystals deposits depth dikes economic geology engineering epidote faults feet feldspar field fissure vein formation fractures galena Geological geologist gold gossan granite hematite Hill Huronian igneous rocks important intrusive investigation iron Lake Superior later lava less lignite limestone lodes magma magnetite masses material metals metamorphism microscope miles mineral Mining District nickel occur origin oxide paper phases plates present probably production pyrite pyrrhotite quartz quartz veins region sandstone schists scientific secondary sedimentary sediments sericite shaft shale silicates silver smaltite solution specimens structure sulphate sulphides surface syncline thickness tion U. S. Geol U. S. Geological Survey United States Geological vertical volcanic zinc zone