684 



INDEX. 



Underground water (see Ground- 

 water) 



Undertow, 341 

 deposition by, 355 

 erosion by, 342, 347 



United States Geological Survey, 

 VI., 32 



Upham, W., 388 



Uprooting of trees, 40 



Uralite, 431 



Uruguay River, sediment carried 

 by, 107 



Usiglio, 375 



Valleys, 



affected by folds, 154 

 antecedent (see Streams, an- 

 tecedent) 

 canoe-shaped, 155 

 consequent, 78 

 courses of, 77 



development of, 63, 70, 73, 80 

 hanging, 164, 290 

 limits of growth, 67 

 oldest parts, 76 

 profiles of, 66 

 relations to lakes, 74 

 slopes of, 94 

 special forms of, 94 

 structural, 77 



struggle for existence among, 

 100 

 Van Hise, C. R., 219, 434, 448, 

 474. 479, 504, 543, 555, 570 

 Vegetation, 



effect on dunes, 29 

 effect on erosion, 131, 644 

 ' effect on sediments, 645 

 effect on weathering, 131 

 Veins, 223, 428, 511 

 Vermes, geologic contribution 



of, 662 

 Vermeule, C. C, 109 

 Vertebrata, geologic contribu- 

 tion of, 663 

 Vesuvius, 605 



Virginia, natural bridge of, 156 

 Viridite, 467 



Volcanic action, causes of, 623- 

 633 

 activity, periodicity of, 607 

 ash, 23, 404, 592, 617 

 bombs, 406, 592, 617 

 cinders, 592 

 cones, 500 

 debris in sea, 381 

 dust (see Volcanic ash) 

 eruptions, 594 



and atmospheric pressure, 



606 

 and tidal strain, 607 

 types of, 593 

 gases, 617-623 

 action of, 617 

 kinds of, 618 

 proportions of, 620, 622 

 sources of, 619, 620, 621 

 633 

 glass (see Obsidian) 

 in sea, 381 



Volcanic mud, 380 



flows of, 610 

 neck, 500 

 plug, 500 

 rocks, 395-418 



residual gases in, 619 

 smoke, 592, 617 

 Volcanoes, 599-611 



coincidence in eruption of, 



606 

 cones of, 608 

 distribution of, in curved lines, 



603 

 distribution of, in latitude, 



603 

 distribution of, in relation to 



crustal movements, 601, 



604, 628 

 distribution of, in relation to 



land and sea, 599 

 distribution of, in time, 599 

 independence of, 605, 623 

 periodicity of, 607 

 relations of, 604-607 

 relations to one another, 605 

 Volume of ocean, 325 

 Vuggs, 437 



Vulcanism, 2, 590-637 

 causes of, 623-633 

 effects on coast-hnes, 332 

 in ocean, 332 

 Vulcanism and deep sedimenta- 

 tion, 629 

 ground-water, 635 

 rotation, 603 



Wacke, 422, 473, 645 



Wad, 467 



Walcott, C. D., 194, 246, 371, 



438, 440, 441, 502, 503, 509 

 Wallace, A. R., 665, 668 

 Walther, J., 50, 670 

 Warming, E., 667 

 Warping, effect of, on streams, 

 171 



of earth's crust, 526, 541, 542 

 Wasatch Mountains, lateral mo- 

 raines of, 303 

 Washington, H. S., 412, 451, 



573 

 Waste of glaciers, 273 

 Water (see Streams, Ground- 

 water, Ocean, etc.) 



amount of, 7 



geologic activity of, 8 

 Water-gaps, 141, 167 

 Waterfalls, 132 



development of, 133 



Minnehaha, 137 



Niagara, 139 



Shoshone, 135 



St. Anthony, 135 



Upper Yosemite, 138 



Yellowstone, 135 

 Waterfalls and sediment, 137 

 Water-lime, 473 

 Water-table, 71. 215 

 Water-vapor, climatic effects of, 



643 

 Wave-built terraces, 363 



Wave-cut terraces, 351, 352 

 Wave erosion, 342-354 



range of, 346 



topographic features devel- 

 oped by, 349 

 Wave erosion and horizontal 

 configuration, 353, 363, 364 

 Wave-marks, 490 

 Wave-motion, 339 

 Waves, 339 



deposition by, 355 



erosion by, 342-354 



force of, 344 



transportation by, 354 



work of, 342-366 

 Weathering, 54, no, 226 



affected by life, 644 



aided by plants, 112 



aided by hot vapors, 113 



effect of gravity, 112 



effect of joints, 151, 153 



importance of, in valley 

 growth, 114 

 Wedgework of ice, 45, 48, 150 



of roots, 112, 131, 150 

 Weed, W. H., 225, 237, 474, 



656 

 Wells, 



artesian, 242 



flowing, 234, 242, 243 

 Wheehng well, temperature of, 



569 

 White glacier, 263 

 Whitfield, J. E. (and Gooch, F. 



A.), 236 

 WilUams, H. S., 658 

 Willis, B., 157, 168, 169, 257, 

 344, 355, 365, 516, 543, 

 550 

 Winchell, H. V., 474 

 Wind, abrasion by, 38 



effects on plants, 40 



movements of sea, generated 

 by, 336 



transports organisms, 41 



work of, 21-41 

 Wind-blown dust, 22 

 Wind-blown sands, 25 

 Wind-ripples, 37 

 Winslow, A., 474 

 Wisconsin River, dells of, 152 

 Woodward, R. S., 560, 581 

 Work of glaciers, 281 

 Wyandotte Cave, 227, 228 



Yazoo River, 188 

 Yellowstone Park, 



geysers of, 238 



hot springs of, 225 

 Yellowstone River, 



canyon of, 100 



falls of, 135 

 Yukon River, delta of, 202 



Zeiller, 652 



Zeolites, 428, 467 



Zircon, 467 



Zittel, K. von, 658, 659 



Zone of fracture, 219, 427 



