Geological Survey of Michigan

Altitude amygdaloid amygdaloid belt amygdules anhydrite arenaceous argillitic augite Bay City Berea Black shale bluffs borings brecciated brine brown C. E. Wright calcspar Calumet chloride clay coal coarse compact diabase conglomerate belt copper County crystalline datolite delessite deposits diabase belt diorite dolomite drift east epidote explorations exposed exposures farther feet feldspar felsite ferruginous fine-grained fissure vein formation formed geological grains granite groundmass gypsum Helderberg hematite horizon hornblende Huron Huronian incloses intersected iron Keweenaw Lake laminated laumonite layers ledges light colored limestone limonitic localities lower magnetic magnetite mica-schists Michigamme Michigan mile mineral mining Montreal River north side occur Ohio ore-bearing orthoclase outcrops oxide plagioclase Plate porphyry prehnite quartz quartzite red colored rock beds rock belt rock masses rock series Rominger salt sand sandrock sandstone schistose schists seams sedimentary shale shore slate slate-rock slaty strata structure succession surface thickness Total depth Winchell