When the geologist proceeds systematically to trace the series of these phenomena, to ascertain their causes, and to connect together all the indications of change that are found in the organic and inorganic kingdoms of nature, he attempts the structure of a THEORY OF CREATION, which shall embrace the whole course of the world, from the earliest to the present times; and which, it may reasonably be concluded, may be resolved into one great cycle, yet unfinished. But for this the materials of the science are by no means prepared, nor is its progress sufficiently advanced. The history of organic remains forms an interesting branch of descriptive geology, where, it may be said, we find the medal-stamps of creation in the first forms of organic life that came from the hands of the Creator. The fact is all important, and the science is prepared to announce it, that in the lowest fossiliferous strata of the earth, VEGETABLES appear among the first of all living things: the impressions of plants, and entire beds of carbonaceous matter, are found in the most ancient strata of the Silurian group of rocks. Nor less important is the fact, that the fossils which next arrest the attention are the remains of marine animals, myriads of shells, and vast numbers of fishes. Then, in the ascending series of strata, the foot-prints of birds are lower down than the impressions of the beasts of the earth. The sea, it is next discovered, swarmed with huge reptilian bodies, before mammalian quadrupeds and cattle had yet a place on dry land; and man, the noblest specimen of organic structure, the crowning apex of the pyramid of terrestrial being, is, according to the geological narrative, precisely in his place—no bone nor fragment of his kind, having been detected in the solid frame of the globe.