Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/233

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The design of the Creator seems at all times to have been, to fill the waters of the seas, and cover the surface of the earth with the greatest possible amount of organized beings enjoying life; and the same expedient of adapting the vegetable kingdom to become the basis of the life of animals, and of multiplying largely the amount of animal existence by the addition of Carnivora to the Herbivora, appears to have prevailed from the first commencement of organic life unto the present hour.

Mr. De la Beche has recently published a list of the specific gravities of living shells of different genera, from which he shows that their weight and strength are varied in accommodation to the habits and habitation of the animals by which they are respectively constructed; and points out evidence of design, such as we discover, in all carefully conducted investigations of the works of nature, whether among the existing or extinct forms of the animal creation.

lipods of the Transition and Secondary strata were furnished with an operculum, as if to protect them against the carnivorous Cephalopods which then prevailed abundantly; but that in the Tertiary formations, numerous herbivorous genera appear, which are not furnished with opercula, as if no longer requiring' the protection of such a shield, after the extinction of the Ammonites and of many cognate genera of carnivorous Trachelipods, at the termination of the Secondary period, i. e. after the deposition of the Chalk formation.