Obviously, if the earliest fossiliferous rocks now known are coeval with the commencement of life, and if their contents give us any just conception of the nature and the extent of the earliest fauna and flora, the insignificant amount of modification which can be demonstrated to have taken place in any one group of animals, or plants, is quite incompatible with the hypothesis that all living forms are the results of a necessary process of progressive development, entirely comprised within the time represented by the fossiliferous rocks.
Contrariwise, any admissible hypothesis of progressive modification must be compatible with persistence without progression, through indefinite periods. And should such an hypothesis eventually be proved to be true, in the only way in which it can be demonstrated, viz. by observation and experiment upon the existing forms of life, the conclusion will inevitably present itself, that the Palæozoic, Mesozoic, and Cainozoic faunæ and floræ, taken together, bear somewhat the same proportion to the whole series of living beings which have occupied this globe, as the existing fauna and flora do to them.
Such are the results of palæontology as they appear, and have for some years appeared, to the mind of an inquirer who regards that study simply as one of the applications of the great biological sciences, and who desires to see it placed upon the same sound basis as other branches of physical inquiry. If the arguments which have been brought forward are valid, probably no one, in view of the present state of opinion, will be inclined to think the time wasted which has been spent upon their elaboration.
FOOTNOTES:
[33] "Le plus grand service qu'on puisse rendre à la science est d'y faire place nette avant d'y rien construire."—Cuvier.
[34] Anniversary Address for 1851, Quart. Journ. Geol. Soc. vol. vii.
[35] See Hooker's "Introductory Essay to the Flora of Tasmania," p. xxiii.
[36] See the abstract of a Lecture "On the Persistent Types of Animal Life" in the "Notices of the Meetings of the Royal Institution of Great Britain," June 3, 1859, vol. iii. p. 151.
[37] "Memoirs of the Geological Survey of the United Kingdom.—Decade x. Preliminary Essay upon the Systematic Arrangement of the Fishes of the Devonian Epoch."
[38] As this Address is passing through the press (March 7, 1862), evidence lies before me of the existence of a new Labyrinthodont (Pholidogaster), from the Edinburgh coal-field, with well-ossified vertebral centra.