.
----, 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.

Volcanoe