--, their successive creation and extinction, 678, 689, 707.
----, effect of changes in geography, climate, &c., on their
distribution, 105, 690, 697.
----, superior longevity of molluscous, 76.

Specific centres, doctrine of, 630.

Spence, Mr., on insects, cited, 606, 655, 673.

Spitzbergen, glaciers of, 96.

Spix, M., on animals drifted by Amazon, 641.
----, on Brazil, 682.

Spontaneous generation, theory of, 22.

Springs, origin of, 232.
----, the theory of, illustrated by bored wells, 233.
----, most abundant in volcanic regions, 237.
----, affected by earthquake, 237, 453, 456, 483, 494.
----, transporting power of, 238.
----, calcareous, 239.
----, sulphureous and gypseous, 245.
----, siliceous, 246.
----, ferruginous, 249.
----, brine, 247.
----, carbonated, 248.
----, petroleum, 250.

Squirrels, migrations of, 637.

Stabiae, buried city of, 394.

Stalagmite alternating with alluvium in caves, 737.

Stars, variable splendor of, 128.

Statical figure of the earth, 534, 544.

Stations of plants, description of, 614.
----, of animals, 677.

Stelluti on organic remains, 23.

Steno, opinions of, 23.

Stephenson on eruption in Iceland, 425.

Stephenson, Mr. R., on level of Red Sea and Mediterranean, 294.

Stevenson, Mr., on drift stones on Bell-Rock, 302.
----, on the German Ocean, 315, 340.
----, on waste of cliffs, 324.

Stockholm, rise of land near, 526, 527.

Stokes, Mr., on mineralization of plants, 747.

Stonesfleld, fossils of, 138, 145.

Storm of November, 1824, effect of, 317, 318, 320.

Strabo cited, 14, 260, 355, 361.
----, geology of, 14.

Strachey, Capt, R., on delta of Ganges, 283.

Straits of Dover, formation of, 315.
----, their depth, 315.

Straits of Gibraltar, currents in, &c., 333, 335.

Strata, laws governing deposition of, 188.
----, slow deposition of, proved by fossils, 154.
----, on consolidation of, 175.

Stratifications in deltas, causes of, 287.
----, of debris deposited by currents, 288.
----, unconformable, inferences derived from, 187.

Strabo, hypothesis of, 14.

Strickland, Mr., on tertiary strata, Cropthorn, 76.
----, on dodo, 684.

Stromboli, its appearance during Calabrlan earthquakes, 488.
----, constancy in eruption, 546, 561.

Stufas, jets of steam in volcanic regions, 237, 546.

Stutchbury, Mr., on coral i