Volcanoes of North America: A Reading Lesson for Students of Geography and Geology

acid activity Alaska basalt become beds belt beneath California canic central characteristic Cinder cone cloud Columbia lava column composed condition Conseguina coulée crystals Deccan trap deep deposits diameter dikes earth earth's crust elevation emitted erosion escape explosions extinct extruded feet feldspar fissures fluid formed fractures fragments frequently fumaroles gases glaciers height highly heated igneous rocks instances interior intruded sheets island known Krakatoa lake lapilli lava flows lava sheets lava streams layers liquid lava magma mass material Mexico miles minerals molten rock Mono craters nearly North America numerous observations occur opening origin Paoha Island peaks Pele's hair pile plastic plutonic portion pressure pumice reached REESE LIBRARY region rhyolite rise scoria sedimentary seen sides silica slag slopes steam Stromboli structure summit surface tain thick tion trachyte U. S. Geological Survey vapor vast vents Vesuvius violent volcanic dust volcanic eruptions volcanic mountains volcanic rocks volcanoes