instance, without being convinced that the beings, whose organs they formed, belonged to an order of things entirely different from the present. Gigantic vegetables, more nearly allied to the palms of the equatorial countries than to any other plants, can only be imagined to have lived in a very high temperature; and the immense reptiles, the megalosauri with paddles instead of legs and clothed in mail, in size equal or even superior to the whale; and the great amphibia, plethiosauri, with bodies like turtles, but furnished with necks longer than their bodies, probably to enable them to feed on vegetables growing in the shallows of the primitive ocean, seem to show a state in which low lands or extensive shores rose above an immense calm sea, and when there were no great mountain, chains to produce inequalities of temperature, tempests, or storms. Were the surface of the earth now to be carried down into the depths of the ocean, or were some great revolution of the waters to cover the existing land, and it was again to be elevated by fire, covered with consolidated depositions of sand or mud, how entirely different would it be in its characters from any of the secondary strata. Its great features would undoubtedly be the works of man--hewn stones, and statues of bronze and marble, and tools of iron--and human remains would be more common than those of animals on the greatest part of the surface; the columns of Paestum or of Agrigentum, or the immense iron and granite bridges of the Thames, would offer a striking contrast to the bones of the crocodiles or sauri in the older rocks, or even to those of the mammoth or elephas primogenius in the diluvial strata. And whoever dwells upon this subject must be convinced that the present order of things, and the comparatively recent existence of man as the master of the globe, is as certain as the destruction of a former and a different order and the extinction of a number of living forms which have now no types in being, and which have left their remains wonderful monuments of the revolutions of Nature.