remote parts of the earth have very different animals; the preservation of organic remains at the mouth of the Mississippi being no index of what is going on at the mouth of the Ganges. While it is possible, it is certainly not proved by the structure of the rocks, their deposition, and organic remains, that the whole earth has passed at the same time successively through the Primary, Secondary, and Tertiary Ages. The limits of this essay do not admit of the further discussion of this subject; nor, indeed, is it necessary, as the question has been thoroughly argued by Herbert Spencer in his "Illogical Geology." The disputes of the Neptunists and Plutonists ought to be a warning to Geologists not to apply generalizations, drawn from limited data, to the whole earth. In the present state of Geology we should receive all conclusions with great caution, being prepared at any moment to have them modified or even disproved by future research. Notwithstanding the difficulty of obtaining fossils, the injuries they often have received in being removed from the rocks, that many are lost or destroyed through the ignorance of the workmen who are often the first to find them, together with the fact that the chance of plants and animals being preserved is very small, remembering how the remains of an animal, dying at the present day, are picked to pieces, get separated, and are often finally destroyed,—yet the museums in different parts of the world contain numerous organic remains on which is based the science of extinct plants and animals, or Paleontology, the conclusions of which science are important proofs of the truth of the theory of the evolution of the higher forms of life from the lower. The opponents of the transmutation of species argued fifty years ago. If the higher forms have descended from the lower, where are the missing links? Paleontology has answered that objection by supplying the missing links, such as the intermediate forms which bind together the Rhinoceros
