Professor W. C. Williamson likewise remarks[263] on these lacunæ which persistently occur at crucial points:
If [he writes] these generic types [of plants] first came before us in such clearly defined forms, when and where did the transitional states make their appearance? The extreme evolutionists constantly affirm of those[{232}] who believe in special creation that they "habitually suppose the origination to occur in some region remote from human observation," and that "the conception survives only in connexion with imagined places where the order of organic phenomena is unknown." It is legitimate to retort upon them that they as habitually resort to "strata now covered by the sea"—to rocks "from which all traces of such fossils as they probably included have been obliterated by igneous action," and to mysterious "migrations from pre-existing continents to continents that were step by step emerging from the ocean." Unfortunately, so far as the vegetable kingdom is concerned, we have as yet failed to discover any traces of these mysterious strata or hypothetical continents in which the transitions from one plant-type to another were being brought about. The believers in special creations are not the only reasoners who have made free use of hypothetical possibilities.
He presently adds:
We have no evidence that unaided Nature has produced a single new type during the historic period. We can only conclude that the wonderful outburst of genetic activity which characterized the Tertiary age was due to some unknown factor, which then operated with an energy to which the earth was a stranger, both previously and subsequently. The knowledge of this factor is what we need in order to perfect our philosophy; and until we obtain that knowledge, many things must remain unaccounted for, so far as primeval vegetation is concerned.
And elsewhere Professor Williamson reiterates the same idea:[264]
I contend stoutly [he says] that, however numerous may be the facts that sustain the doctrine of evolution (and I am prepared to admit that there are many that do so in a remarkable manner), this unexplained outburst of new life demands the recognition of some factor not hitherto admitted into the calculations of the evolutionist school.
In the record of fossil fishes he finds some features which are particularly hard to harmonize with any theory of genetic evolution.[265] Amongst the very earliest representatives of this class, even in the upper Silurian, are found remains of sharks, in his opinion the highest order of fish, and in the Devonian and Carboniferous above, of Ganoids armour clad, like the sturgeon. But nowhere below the Chalk do we find a single scale of Cycloids or Ctenoids, which in regard alike of the scales themselves, of the nervous system and of the reproductive organs, are much below the sharks, and not above the Ganoids. To complicate matters still more, however, the skeleton of Cycloids and Ctenoids is more highly organized than that of the others, and it is thus equally impossible to describe them as progressive or as retrogressive types.[266]
Over and above this absence of intermediate or link forms, the witnesses who have been cited insist[{234}] on the fact that those earliest found are not simple or generalized representatives of their respective types, as the theory of genetic evolution requires them to be, but are as perfectly finished and specialized as those appearing in later ages. To their testimony on this point may be added that of Professor Huxley, who while frankly confessing that he would be glad enough to find evidence in favour of such progressive modification, was constrained by his love of scientific truth to bear witness as follows:[267]
The only safe and unquestionable testimony we can procure—positive evidence—fails to demonstrate any sort of progressive modification towards a less embryonic, or less generalized type, in a great many groups of animals of long-continued geological existence. In these groups there is abundant evidence of variation—none of what is generally understood as progression; and if the known geological record is to be regarded as even any considerable fragment of the whole, it is inconceivable that any theory of a necessarily progressive development can stand, for the numerous orders and families cited afford no trace of such a process.