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Whence came that primordial organism whose transmuted descendants make up the existing faunas and floras of the globe? There was a time, soon after the doctrine of evolution gained a hearing, when the answer to that question seemed to some scientists of authority to have been given by experiment.
In South America, in the Pampean formation, he had discovered "great fossil animals covered with armor like that on the existing armadillos," and had been struck with this similarity of type between ancient and existing faunas of the same region.
Darwin relies upon indirect proofs, the bearing of which is real and incontestable;" who concedes that "his theory accords very well with the great facts of comparative anatomy and zoology comes in admirably to explain unity of composition of organisms, also to explain rudimentary and representative organs, and the natural series of genera and species equally corresponds with many paleontological data agrees well with the specific resemblances which exist between two successive faunas, with the parallelism which is sometimes observed between the series of paleontological succession and of embryonal development," etc.; and finally, although he does not accept the theory in these results, he allows that "it appears to offer the best means of explaining the manner in which organized beings were produced in epochs anterior to our own."
The general fact, however, that the fossil fauna of each period as a whole is nearly intermediate in character between the preceding and the succeeding faunas, is much relied on.
For those who, with Agassiz, doubt the specific identity in any of these cases, and those who say, with Pictet, that "the later tertiary deposits contain in general the débris of species very nearly related to those which still exist, belonging to the same genera, but specifically different," may also agree with Pictet that the nearly related species of successive faunas must or may have had "a material connection."
Should it be replied, as it may fairly be, that this correspondence from which the synchronism of distant formations is inferred, is not a correspondence between particular species or particular genera, but between the general characters of the contained assemblages of fossils between the facies of the two Faunas; the rejoinder is, that though such correspondence is a stronger evidence of synchronism it is still an insufficient one.
The Pennsylvania State Game Commission to-day stands in urgent need of active, vigorous and persistent assistance from the Philadelphia Academy in the fierce campaign already in progress for additional protective laws. Will that help be given? Academic research work is all very well, but it does not save faunas from annihilation.
These geographical speculations were indulged in ten years after Edward Forbes had published his bold generalisations on the geological changes which accompanied the successive establishment of the Scandinavian, Germanic, and other living floras and faunas in the British Islands, and, like the theories of his predecessor, were the results of much reflection on a vast body of geological facts.
So that three marine faunas range northward and southward in parallel lines not far from each other, under corresponding climate; but from being separated from each other by impassable barriers, either of land or open sea, they are almost wholly distinct.
As to the former greater distinction of the North and South American faunas, I think I am right. Yet in South America they were so enormously developed in the Pliocene epoch that we know, if there is any such thing as Evolution, etc., that strange ancestral forms must have preceded them in Miocene times.
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