Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/60

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Beginning with the animal kingdom, we find the four great existing divisions of Vertebrata, Mollusca, Articulata, and Radiata, to have been coeval with the commencement of organic life upon our globe.

No higher condition of Vertebrata has been yet discovered in the transition formation than that of fishes, whose history will be reserved for a subsequent chapter.

The Mollusca, in the transition series, afford examples of several families; and many genera, which seem at that time to have been universally diffused over all parts of the world; Some of these, (e. g, the Orthoceratite; Spirifer, and Producta) became extinct at an early period in the history of stratification, whilst other genera (as the Nautilus and Terebratula) have continued through all formations unto the present hour.

The earliest examples of Articulated animals are those