It was long ages before trees with deciduous leaves appeared. The growth of animal life is equally instructive. First invertebrate life, then the lowest forms of vertebrate life. The fishes are followed by amphibians—then reptiles, then birds. The first mammal to appear was the lowest organized of all—the marsupials. And we have seen the sudden increase of mammalian life in Tertiary times. We notice, in all the divisions of life, a beginning, a culmination, and a decline. There has never been such a growth of flowerless plants as in the Paleozoic, and flowering plants probably culminated in the Miocene. The same rule holds good for the animal world also. As man is the most highly organized of all the animals, we can not hope to find any evidence of his presence until we find proofs of the presence of all the lower types of life. Of course future discoveries may change our knowledge when the series is complete; but, from our present stand-point, he could not have lived before the Miocene Age, and we have seen how faint and indecisive are the proofs of his presence even then. But should it finally be proved, beyond all dispute, that man did live in the Miocene Age, we must observe that this is but a small portion, but a minute fraction, of the great lapse of time since life appeared on the globe. We are a creation of but yesterday, even granting all that the most enthusiastic believer in the antiquity of man can claim. The Mastodon. REFERENCES The manuscript of this chapter was submitted to Prof. Winchell, of the University of Michigan, for criticism. Dana’s “Manual of Geology,” p. 146. Ibid. p. 147. Nicholson’s “Manual of Zoology,” p. 59. Dana’s “Manual of Geology,” p. 74. Nicholson’s “Manual of Zoology,” p. 42. Dana’s “Manual of Geology,” p. 323. Nicholson’s “Zoology,” p. 402. Dana’s “Geology,” p. 302. Dawkins’s “Early Man in Britain,” p. 6. Dana’s “Geology,” p. 382. Haywood’s, Heer’s, “Primeval World of Switzerland.” Dana’s “Man. Geology,” p.395. Nicholson’s “Man. Zoology,” p.42. Marsh: “American Assoc. Rep.,” 1877. Marsh: “American Assoc. Rep.,” 1877. Dawkins’s “Early Man in Britain,” p. 6. Nicholson’s “Manual of Zoology,” pp. 419 and 504.