V.

Val d'Arno, Upper, effect of destruction of forests in, 712.

Val del Bove on Etna described, 403. ----, form, composition, and origin of dikes in, 406. ----, lavas and breccias of the, 411. ----, origin of the, 413. ----, floods in, 411.

Val di Calanna, 405, 407, 410.

Val di Noto, Dolomieu on the, 49.

Valdivia, earthquake at, 453.

Valenciennes, M., on fish not crossing the Atlantic, 647.

Valley, newly formed in Georgia, U. S., 205.

Valleys, Targioni on origin of, 40. ----, excavation of, in Central France, 213. ----, of elevation, section of, 420. ----, on Etna, account of, 404. ----, the excavation of, assisted by earthquakes, 484.

Vallisneri on the origin of springs, 33. ----, on marine deposits of Italy, 34. ----, cited, 34, 35, 52.

Valparaiso, changes caused by earthquakes at, 457, 517, 761.

Van Dieman's Land, climate of, 97.

Vedas, sacred hymns of, 4.

Vegetable soil, why it does not increase, 709. ----, how formed, 710.

Vegetation, luxuriant, not required to support large animals, 82. ----, centres of, 703. ----, its conservative influence, 710, 711. ----, its influence on climate, 713.

Veins, mineral, on their formation, 484. ----, of lava. _See_ Dikes.

Verneuil, M. de, on lowland of Siberia, 84.

Verona, fossils of, 20, 22, 34. ----, Arduino on mountains of, 41.

Verstegan, on separation of England from France, 315, 642.

Vertebrated animals in oldest strata, 135.

Vessels, fossil. _See_ Ships.

Vesta, temple of, 212.

Vesuvius, excavation of tuff on, 213. ----, history of, 263, 374. ----, eruptions of, 364, 374. ----, dikes of, 379. ----, lava of, 384. ----, structure and origin of the cone of, 383. ----, and Somma, probable section of, 381. ----, volcanic alluvium on, 728.

Vicentin, Dolomieu on the, 49. ----, submarine lavas of the, 71.

Victoria land, skirted by ice, 99.

Vidal, Capt., on Rockhall bank, 773.

Villages buried by landslips, 732.

Virlet, M., on Samothracian deluge, 356. ----, on volcanoes of Greece, 355. ----, on Santorin, 443, 445, 446. ----, on corrosion of rocks by gases, 733. ----, on human bones imbedded in Morea, 735.

Vivarais, basalts of the, 48.

Volcanic action, defined, 345. ----, power adequate to effect lateral pressure, 172. ----, lines, 169, 352. ----, craters in Galapagos with southern side lowest, 783. ----, action, uniformity of, 162, 711. ----, cones, truncation of, 352, 493. ----, their perfect state no proof of relative age, 712. ----, conglomerates, 438. ----, dikes. _See_ Dikes. ----, eruptions, causes of, 542. ----, average number of, per annum, 450. ----, formations, fossils in, 349, 728. ----, products, mineral composition of, 449. ----, regions, their geographical boundaries, 346. ----, map showing extent of, 351. ----, rocks, subterranean, 178, 450. ----, of all geological periods, 160.

Volcanoes, safety-valves according to Strabo, 15. ----, remarks on their position, 346, 355. ----, and earthquakes, effects of same causes, 345. ----, agency of water in, 545. ----, mode of computing the age of, 420. ----, sometimes inactive for centuries, 346, 421. ----, of Sandwich Islands, 354, 372, 548, 383, 429. ----, chemical theory of, 546. ----, mud, 447. ----, "no safety-valves," Dana on, 553.

Voltaire on systems of geology, 54.

Volterra, Mattani, on fossils of, 34.

Von Baer, Prof., on frozen soil of Siberia, 84. ----, on ice-drifted rocks, 231.

Von Buch on rise of land in Sweden, 523, 526. ----, on volcanic lines, 352. ----, on volcanoes of Greece, 355. ----, on formation of Monte Nuovo, 369. ----, on Vesuvius and Somma, 367, 380, 382, 384. ----, on eruption in Lancerote, 436. ----, on glaciers, 228. ----, on new islands, 468. ----, on volcanic regions, 346.

Von Hoff. _See_ Hoff.

Vulcanists and Neptunists, factions of, 50, 55.

Vultur, Mount, 356.

Vultures, range of, 643.

W.

Wallerius, theory of, 45.

Wallich, Dr., on Ava fossils, 28. ----, on wood in peat near Calcutta, 280.

Warping, land gained by, 288, 339.

Water, action of running, 204. ----, its power on freezing, 204. ----, excavating power of, 204. ----, transporting power of, 204. ----, sorting power of, 286. ----, agency of, in volcanoes, 548.

Waterhouse, Mr., of British Museum, on provinces of indigenous land quadrupeds, 631.

Wealden strata, fossils of, 117, 137, 140.

Webster, Dr., of Nova Scotia, on rain-prints, 202.

Wells, artesian, 233.

Wener, Lake, strata near, 527.

Werner, Professor of Mineralogy at Freyberg, 1775, 46. ----, his lecture, 47. ----, on granite of the Hartz, 47. ----, principal merit of his system, 48. ----, technical terms of, 58. ----, on transition rocks, 176. . West Indian land quadrupeds, 634.

West Indies, earthquakes in, 29, 350, 505. ----, active volcanoes in, 350.

Whales stranded, 771.

Whewell, Rev. Dr., on modern progress of geology, 59. ----, on the tides, 332.

Whirlwinds, violent, during eruption in Sumbawa, 465.

Whirlwind, dispersion of seeds by, 619.

Whiston, his theory of the earth, 32.

White Mountains, landslips in the, 209.

Whitehurst, theory of, 1778, 45. ----, on subsidence at Lisbon, 495.

Wildenow on diffusion of plants by man, 626. ----, on centres of vegetable creation, 703.

Wilkinson, Sir J. G., on deposits of Nile, 262. ----, on sand drift in Egypt, 726.

Wilson, Prof., on cosmogony of Vedas, 4.

Winds, trade, 106, 295. ----, currents caused by the, 293. ----, sand drifted by the, 307, 726.

Wolf, and dog, distinct species, 585. ----, hybrids between the, 601. ----, drifted to sea on ice, 640. ----, extirpated in Great Britain, 683.

Wollaston, Dr., on water of Mediterranean, 334.

Wood, Mr. S., on fossil quadrumana, 144.

Wood impregnated with salt water when sunk to great depths, 743. ----, drift, 90, 268, 640, 743. ----, converted into lignite, 759.

Woodward, theory of, 31, 84, 54, 66.

Wrecks, number of, annually, 754, 755.