CHAPTER XXXIX. Geographical distribution and migrations of fish--Of testacea--Of zoophytes--Of insects--Geographical distribution and diffusion of the human race 646
CHAPTER XL. Theories respecting the original introduction of species--Reciprocal influence of species on each other 665
CHAPTERS XLI. XLII. Extinction of species--How every extension of the range of a species alters the condition of many others--Effect of changes of climate 677, 689
CHAPTER XLIII. Creation of species--Whether the loss of certain animals and plants is compensated by the introduction of new species 701
CHAPTER XLIV. Modifications in physical geography caused by organic beings 708
CHAPTER XLV. Imbedding of organic remains in peat, blown sand, and volcanic ejections 718
CHAPTER XLVI. Imbedding of the same in alluvial deposits and in caves 730
CHAPTER XLVII. Imbedding of organic remains in aqueous deposits--Terrestrial plants--Insects, reptiles, birds, quadrupeds 742
CHAPTER XLVIII. Imbedding of the remains of man and his works 753
CHAPTER XLIX. Imbedding of aquatic animals and plants, both freshwater and marine, in aqueous deposits 765
FRONTISPIECE, View of the Temple of Serapis at Puzzuoli in 1836, _to face_ title page.
PLATE 1. Map showing the Area in Europe which has been covered by Water since the beginning of the Eocene Period _to face_ p. 121
2. Boulders drifted by Ice on the Shores of the St. Lawrence 220
3. View looking up the Val del Bove, Etna 403
4. View of the Val del Bove, Etna, as seen from above 404
Geology defined--Compared to History--Its relation to other Physical Sciences--Not to be confounded with Cosmogony.
Geology is the science which investigates the successive changes that have taken place in the organic and inorganic kingdoms of nature; it inquires into the causes of these changes, and the influence which they have exerted in modifying the surface and external structure of our planet.
By these researches into the state of the earth and its inhabitants at former periods, we acquire a more perfect knowledge of its present condition, and more comprehensive views concerning the laws now governing its animate and inanimate productions. When we study history, we obtain a more profound insight into human nature, by instituting a comparison between the present and former states of society. We trace the long series of events which have gradually led to the actual posture of affairs; and by connecting effects with their causes, we are enabled to classify and retain in the memory a multitude of complicated relations--the various peculiarities of national character--the different degrees of moral and intellectual refinement, and numerous other circumstances, which, without historical associations, would be uninteresting or imperfectly understood. As the present condition of nations is the result of many antecedent changes, some extremely remote, and others recent, some gradual, others sudden and violent; so the state, of the natural world is the result of a long succession of events; and if we would enlarge our experience of the present economy of nature, we must investigate the effects of her operations in former epochs.