Grayfish, i, 224 Graylings (fish), xii, 159 Gray Matter, ix, 124; of brain, xv, 63 Great Auk, xii, 265 Great Basin, block mountains in, iii, 138-9; drainage changes in, xiv, 188; faulting in, iii, 89, 229, xiv, 117, 127; formerly submerged, iii, 181; not being worn down, 32; saline lakes of, xiv, 206; streams, base level of, 164; wind-eroded materials of, iii, 73 Great Britain, aerial travel statistics, i, 50; aeronautical research, 51; animals of, xiv, 272-3; coal supply, iii, 345; coast destruction, xiv, 46; empire of, 279; geology related to continent, 271-2; manufacturers, American System in, v, 50; manufacturing future, 173; rainfall of, xiv, 41; recent separation from continent, 30, 271-3; serpents of, xii, 218; soot studies, i, 65; standard units in, iv, 45-6; storm signals, i, 282; thermometer scale in, iv, 136; tides of, xiv, 293-4 "Great Eastern," steamship, v, 193 Greater Antilles, geological history of, xiv, 274-5 Great Indian Earthquake, xiv, 333, 334, 335, 336 (fig.); cause, 340 Great Lakes, commerce on, xiv, 62, 212; fish of, xii, 156, 159; former drainage farther north, iii, 46; level changes in region, 82; origin and history, 146-51, xiv, 61, 62, 201-2, 203; recentness of formation, iii, 12; recessional moraines near, 67; sewage disposal in, viii, 325; sizes and depths, xiv, 204; water supply of Lake cities, 140 Great Plains, elevation of, xiv, 27, 213; evaporation in, 135; geology of, 215; grasses of, xiii, 181, 374, xiv, 380, 381; horses of, xii, 306, 307; pronghorns on, 322-3; red beds, iii, 208; rejuvenation, 230; rodents of, xii, 294; stock-raising on, xiv, 383-4; trees in, xiii, 372-3, 374, xiv, 372; volcanic action in, 318; wind-fertilization of plants, xiii, 149 Great Rift Valley, xiv, 117-21; lakes in, 203; volcanoes of, 317 Great Salt Lake, crustal warping at, iii, 82; history and formation, 152-3, xiv, 207-8; mirages, i, 172; plain of, xiv, 215-16; salt in, iii, 374, viii, 139, 140, 275 Great Sea Waves, xiv, 337-343 Grebes, xii, 250-1 Greece, earthquakes of, xiv, 332, 333-4; geographical changes in, 33; rainfall of, 358; rift valleys in, 123 Greece (ancient), astrology in, ii, 21; Babylonian influences, xvi, 63; civilization conditions, xv, 123; civilization pictured in Odyssey, 324; copyists of, 178-9; foreigners called barbarians, xi, 22; Golden Age, x, 20, xvi, 86-96; musical instruments, xv, 316, 317 (fig.); northern invasion, xiv, 281; religion and science associated, xvi, 44; slavery in, xv, 378-9; timing of orators, v, 62; weather records, i, 67-8 Greek Astronomy, ii, 10-11, 27-36, xvi, 81-2, 90-1 Greek Language, xv, 162