Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/337

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was stated in our Chapter on Strata of the Transition Series, that some of their most abundant animal remains are fossil Corals or Polyparies. These were derived from an order of animals long considered to be allied to marine plants, and designated by the name of Zoophytes; they are usually fixed, like plants, to all parts of the bottom of the sea in warm climates which are not too deep to be below the influence of solar heat and light, and in many species, send forth branches, assuming in some degree the form and aspect of vegetables. These coralline bodies are the production of Polypes, nearly allied to the common Actinia, or Sea Anemone of our own shores. See Pl. 54. Fig. 4. Some of them, e. g. the Caryophyllia, see Pl. 54. Figs. 9, 10. are solitary, each forming its own independent stem and support; others are gregarious, or confluent; living together on the same common base or Polypary, which is covered by a thin gelatinous substance, on the surface of which are scattered tentacula, corresponding with the stars on the surface of the coral, (see Pl. 54. Fig. 5.)

Le Sueur, who observed them in the West Indies, describes these Polypes, when expanded in calm weather at the bottom of the sea, as covering their stony receptacles with a continuous sheet of most brilliant colours.

The gelatinous bodies of these Polypes are furnished with the power of secreting carbonate of Lime, with which they form a basis of attachment, and cell of retreat. These calcareous cells not only endure beyond the life of the Polypes that secreted them, but approach so nearly to Limestone in their chemical composition, that at the death of the