[254] See Lyell's Manual of Elementary Geology, ch. 5.
[255] See the Author's Anniversary Address, Quart. Journ. Geol. Soc. 1850, vol. vi. p. 46, from which some of the above passages are extracted.
[256] See Lyell's Manual of Elementary Geology.
[257] Reports to Brit. Assoc. 1842, 1843, and Introd. to Brit. Foss. Mamm. p. 31. The conchological evidence respecting the British Miocene, Pliocene, and Pleistocene fossils, examined by Mr. Forbes, in the paper before cited, p. 88, note, bear out some of the most important conclusions of M. Deshayes, quoted by me in the first edition of the Principles, 1831, and the recent observations of Philippi in regard to the passage of species from one formation to another. I refer to these authorities more especially because this doctrine of a gradual transition has been opposed by some living naturalists of high distinction, among whom I may mention M.A. d'Orbigny and M. Agassiz. I have long been convinced that we must abandon many of the identifications formerly made of Eocene with recent shells; but some errors of this kind do not affect the general reasoning on the subject. See a discussion on this question, Quarterly Journ. of Geog. Soc., No. 5, p. 47 Feb. 1846.
[258] Darwin's Journal, p. 163. 2d. ed. p. 139.
[259] Journ. Roy. Geograph. Soc. vol. iii. p. 142.
[260] Book iii. ch. 50.
[261] Darwin's S. America, pp. 136, 139.
[262] Miller, Phil. Trans. 1851, p. 155.
[263] Phil. Trans. 1850, p. 354.