Page - 342 - in The Origin of Species

342 ORIGIN OF SPECIES not a cave or true lacustrine bed is known belonging to the age of our secondary or palaeozoic formations. y^ But the imperfection in the geological record largely re- sults from another and more important cause than any of the foregoing; namely, from the several formations being sep- arated from each other by wide intervals of time. This doc- trine has been emphatically admitted by many geologists and palaeontologists, who, like E. Forbes, entirely disbelieve in the change of species. When we see the formations tabulated in written works, or when we follow them in nature, it is difficult to avoid believing that they are closely consecutive. But we know, for instance, from Sir R. Murchison's great work on Russia, what wide gaps there are in that country between the superimposed formations ; so it is in North America, and in many other parts of the world. The most skilful geologist, if his attention had been confined exclusively to these large territories, would never have suspected that, during the periods which were blank and barren in his own country, great piles of sediment, charged with new and pe- culiar forms of life, had elsewhere been accumulated. And if, in each separate territory, hardly any idea can be formed of the length of time which has elapsed between the consecu- tive formations, we may infer that this could nowhere be ascertained. The frequent and great changes in the mineral- ogical composition of consecutive formations, generally im- plying great changes in the geography of the surrounding lands, whence the sediment was derived, accord with the belief of vast intervals of time having elapsed between each formation. C' We can, I think, see why the geological formations of each \ region are almost invariably intermittent; that is, have not 1 followed each other in close sequence. Scarcely any fact struck me more when examining many hundred miles of the South American coasts, which have been upraised several hundred feet within the recent period, than the absence of any recent deposits sufficiently extensive to last for even a short geological period. Along the whole west coast, which is inhabited by a peculiar marine fauna, tertiary beds are so poorly developed, that no record of several successive and peculiar marine faunas will probably be preserved to a distant