Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/201

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The genera Trionyx and Emys, present their fossil species. in the Wealden freshwater formations of the Secondary series; and still more abundantly in the Tertiary lacustrine deposites; all these appear to have lived and died, under circumstances analogous to those which attend their cognate species in the lakes and rivers of the present tropics. They have also been found in marine deposites, where their admixture with the remains of Crocodilean animals shows that they were probably drifted, together with them, into the sea, from land, at no great distance.

In the close approximation of the generic characters of these fossil Testudinata, of various and ancient geological epochs, to those of the present day, we have a striking example of the unity of design which has pervaded the construction of animals, from the most distant periods in which these forms of organized beings were also called into existence. As the paddle of the Turtle has at all times been adapted to move in the waves of the sea, so have the feet of the Trionyx and Emys ever been constructed for a more quiescent life in freshwater, whilst those of the Tortoise have been no less uniformly fitted to creep and burrow upon land.

5, Pt. 2, Tab. 14, f. 4, of the Oss. Foss: of Cuvier M. Agassiz has favoured me with the following details respecting important parts which are imperfectly represented in the drawing from which Cuvier's engraving was taken. "The ribs show evidently that it is nearly connected with the genera Chelonia and Sphargis, but referable to no known species; the fingers of the left fore paddle are five in number; the two exterior are the shortest, and have each three articulations; and the three internal fingers, of which the middle one is the longest, have each four articulations, as in the existing genera, Chelonia and Sphargis".