Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/78

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Besides the many extinct species, and extinct genera of Mammalia that are enumerated in this list, the occurrence of nine or ten extinct species of fossil Birds in the Eocene period of the tertiary series, forms a striking phenomenon in the history of organic remains.

In this small number of species, we have seven genera; and these afford examples of four, out of the six great Orders into which the existing Class of Birds. is divided, viz. Accipitres, Gallinaceæ, Grallæ, and Palmipedes. Even the eggs of aquatic birds have been preserved in the lacustrine formations of Cournon, in Auvergne.

It appears that the animal kingdom was thus early established, on the same general principles that now prevail; not only did the four present Classes of Vertebrata exist; and among Mammalia, the Orders Pachydermata, Carnivora, Rodentia, and Marsupialia; but many of the genera also, into which living families are distributed, were associated together in the same system of adaptations and relations, which they hold to each other in the actual creation. The Pachydermata and Rodentia were kept in check by the