Viewing this _olive leaf_ of the Old Red Sandstone as not at all devoid of poetry, our author invites us to a voyage from the latest formation up to the first zone of the Silurian formation,—thus passing from ancient to still more ancient scenes of being, and finding, as at the commencement of our voyage, a graceful intermixture of land and water, continent, river, and sea. But though the existence of a true Placoid, a real vertebrated fish, in the Cambrian limestone of Bala, and of true wood at the base of the Old Red Sandstone, are utterly incompatible with the development hypothesis, its supporters, thus driven to the wall, may take shelter under the vague and unquestioned truth that the lower plants and animals preceded the higher, and that the order of creation was fish, reptiles, birds, mammalia, quadrumana, and man. From this resource, too, our author has cut off his opponents, and proceeds to show that such an order of creation, “at once wonderful and beautiful,” does not afford even the slightest presumption in favor of the hypothesis which it is adduced to support. This argument is carried on in a popular and amusing dialogue in the _eleventh_ chapter. Mr. Miller shows, in the clearest manner, that “superposition is not parental relation,” or that an organism lying above another gives us no ground for believing that the lower organism was the parent of the higher. The theorist, however, looks only at those phases of truth which are in unison with his own views; and, when truth presents no such favorable aspect, he finally wraps himself up in the folds of ignorance and ambiguity—the winding-sheet of error refuted and exposed. We have not yet penetrated, says he, in feeble accents, to the formations which represent the dawn of being, and the simplest organism may yet be detected beneath the lowest fossiliferous rocks. This undoubtedly _may be_, and Sir Charles Lyell and Mr. Leonard Horner are of opinion that such rocks may yet be discovered; while Sir Roderick Murchison and Professor Sedgwick and Mr. Miller are of an opposite opinion. But even were such rocks discovered to-morrow, it would not follow that their organisms gave the least support to the development hypothesis. In the year 1837, when fishes were not discovered in the Upper Silurian rocks, the theorist would have rightly predicted the existence of lower fossiliferous beds; but when they are discovered, and their fossils examined, they furnish the strongest argument that could be desired against the theory they were expected to sustain. This fact, no doubt, is so far in favor of the supposition that there may be still lower fossil-bearing strata; but, as Mr. Miller observes, “The pyramid of organized existence, as it ascends into the by-past eternity, inclines sensibly towards its apex,—that apex of ‘_beginning_’ on which, on far other than geological grounds, it is our privilege to believe. The broad