Page:Popular Science Monthly Volume 75.djvu/545

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That the objection from the general absence of intermediate links between species was a pertinent one he acknowledged with characteristic candor.

He recognized that, so far as geological knowledge then went, whole groups of species sometimes seemed to make their appearance abruptly; though he argued that the increase of such knowledge had steadily tended to diminish this semblance of abruptness. Wholly eliminated these sharp transitions have never been, to this day; the latest authoritative expositor of the general results of paleontology says of d'Orbigny that, though "his ideas" were "too absolute, his observations remain none the less exact in their broad lines, and the sudden replacing of marine faunas, when passing from one stage to another, or even from zone to zone, must be considered almost a general rule." The same writer, who is, of course, a convinced evolutionist, observes:

The second argument of the paleontological opponents of the theory Darwin regarded as still more deserving of serious consideration.

To all these objections, as to that drawn from the absence of a uniformly progressive sequence in the superposition of species of certain classes, Darwin opposed a single reply: "the imperfection of the geological record"—an imperfection due not only to the inadequacy of geological exploration but to the inevitable absence of many chapters from the rock-history itself. Paleontology thus offered to neither side materials for a decisive proof of its case. Darwin's ninth chapter