The American Journal of Science, Band 253

alaskite albite America Bull amphibolite anorthosite basalt beds biotite Bosmina calcite California chemical coast composition conglomerate cordierite crystals curves deformation deposits depth diabase diagram dikes dolomite Elburz equilibrium erosion fabric facies Falalop feet feldspar figure formation formed fragments gabbro garnet Geol glacial glaciers glass glaucophane gneiss grains granite granite pegmatite granophyre Hezardareh hornblende igneous ilmenite indicate intrusive island jadeite Jour Kahrizak Lake lava layers lower magma magnetite marine material metamorphic microperthite miles minerals Mountain norite occur olivine origin pebbles pegmatite percent TiO2 plagioclase plane Pleistocene pollen postglacial present pressure probably pumice pyroxene quartz range ratio red bands reef region rhyolite rocks samples sand sandstone schist sections sedimentary sediments slopes soil species structure suggests surface Teheran temperature thermal tion titaniferous magnetite tubes tuff U. S. Geological Survey varved varved clays volcanic volume zircon zone