s, 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 pla