Report of the Geological Exploration of the Fortieth Parallel, Made by Order of the Secretary of War, Volume 2

acid andesite angle anticlinal apatite Archæan augite basalt base basin biotite bluffs body calcareous Cañon carbonate clays coarse color Colorado compact conglomerate containing Cretaceous crystalline crystals dark deposits diorite east eastern eastward exposed feet feldspar fine-grained flanks fold foot-hills Fork formation forms fossils fragments geological grains granite gray Green River groundmass horizontal hornblende Humboldt Jurassic Lake Laramie lime limestone lithological lower Magnesia marls mass mica microscope miles mineral Mountains nearly north and south northern northward observed occurs orthoclase outcrops overlaid overlying oxide Peak plagioclase Pliocene porphyritic portion Potassa Productus quartz quartzite Quaternary range region resembles rhyolite ridge rock sandstones sanidin schists seams seen shales side Silica slopes Soda southward strata strike structure summit surface texture thickness thin trachyte Triassic triclinic tufa Uinta Upper Coal-Measure valley Vermillion Creek volcanic Wahsatch limestone Weber Quartzite West Humboldt Range western westward