Elements of Geology

abundant accumulated acid agencies already America Amphibians animals Appalachian Archæan basin beds birds Brachiopods called Cambrian cañons carbonate carbonic acid Carboniferous clay climate coal Coal-measures coast condition continent coral Cretaceous crust deposits depth Devonian earth earthquake elevation Eocene epoch erosion eruption Europe evident extinct fauna fissures flora folded fossils geological geologists geysers glacial glacier igneous interior islands Jurassic Lake land land-surface lava Lepidodendron limestone lower mammals marginal Marsh mass matter Mesozoic metamorphism miles Miocene moraines mountains nearly ocean organic origin Palæozoic partly period Permian plants Pliocene portion present pressure probably produced Quaternary reef region represented reptiles rivers rocks sandstone sea-bottom sediments shells shore-line shown Sierra silica Silurian slope sometimes South species square miles strata stratified structure subsidence sulphide surface Tertiary tion Triassic Trilobites unconformity upper usually valleys veins velocity volcanic waves whole