“The _Amphibia_ and _Pisces_ tell the same story. There is not a single class of vertebrated animals which, when it first appears, is represented by analogues of the lowest known members of the same class. Therefore, if there is any truth in the doctrine of evolution, every class must be vastly older than the first record of its appearance upon the surface of the globe. But if considerations of this kind compel us to place the origin of vertebrated animals at a period sufficiently distant from the Upper Silurian, in which the first Elasmobranchs and Ganoids occur, to allow of the evolution of such fishes as these from a vertebrate as simple as the _Amphioxus_, I can only repeat that it is appalling to speculate upon the extent to which that origin must have preceded the epoch of the first recorded appearance of vertebrate life.” “If the theory be true,” says Mr. Darwin, “it is indisputable that before the lowest Cambrian stratum was deposited long periods elapsed—as long as, or probably far longer than, the whole interval from the Cambrian age to the present day; and that during these vast periods the world swarmed with living creatures.”[58] In referring to the abundant and well-developed fauna of the Cambrian period, Sir Andrew C. Ramsay remarks:[59] “In this earliest known varied life we find no evidence of its having lived near the beginning of the Zoological series. In a broad sense, compared with what must have gone before, both biologically and physically, all the phenomena connected with this old period seem, to my mind, to be quite of a recent description; and the climates of seas and lands were of the very same kind as those that the world enjoys at the present day—one proof of which, in my opinion, is the existence of great glacial boulder beds in the Lower Silurian strata of Wigtonshire, west of Loch Ryan.” Professor Haeckel remarks that “Darwin’s theory, as well as that of Lyell, renders the assumption of immense periods absolutely necessary. If the theory of development be true at all, there must certainly have elapsed immense periods, utterly inconceivable to us.” In reference to the foregoing, Mr. Wallace says:[60] “These opinions, and the facts on which they are founded, are so weighty that we can hardly doubt that, if the time since the Cambrian epoch is correctly estimated at 200,000,000 of years,[61] the date of the commencement of life on the earth cannot be much less than 500,000,000; while it may not improbably have been longer, because the reaction of the organism under changes of the environment is believed to have been less active in low and simple than in high and complex forms of life, and thus the processes of organic development may for countless ages have been excessively slow.” [Footnote 56: _Island Life_, p. 204.] [Footnote 57: _Quart. Journ. of Geol. Soc._ vol. xxvi. p. 53.] [Footnote 58: _Origin of Species_, p. 286.] [Footnote 59: _Proceedings of the Royal Society_, No. 152, 1874, p. 342.]