CREATION BY EVOLUTION
more the endless round of scouring, carrying, and depositing. When the crustal movement is so profound as to be dignified by the name revolution there may be marked organic change, stimulated usually by stress of climate, which, either directly or indirectly, has a vast influence upon life. These times of change are therefore critical, both in the elimination of old types and in the acceleration of the evolution of persistent types, so that the whole aspect of nature as revealed by the fossils is profoundly altered. It is not at all surprising, therefore, that the older naturalists, whose orthodoxy caused them to adhere to the doctrine of special creation, imagined a succession of great catastrophes, by which the older faunas were completely destroyed and life was recreated twenty-seven times, the number chosen corresponding to the greater divisions of geologic time. This same explanation was applicable locally to the lesser breaks in the record. But geologists are now convinced of the uniformity of physical conditions throughout geologic time and of the all-sufficiency of the observable phenomena of the present world—of changes in temperature, of rain, snow, and ice, of erosion and geochemical action, of earthquakes and volcanic activity—to account for any and all of the changes, however great their apparent magnitude, in the geologic past. And as a necessary corollary of this doctrine of uniformitarianism in the physical world comes that of continuity with evolutionary change in the organic world. That the evidence for this organic continuity seems meagre is due in part to our lack of perspective, in part to our prepossession with false conceptions or pseudo-conceptions, and in part to our proneness to magnify imperfections that merely mar but do not destroy a most magnificent, clearly unified, and deeply impressive moving spectacle of creation, which at length makes Man the heir of all the ages.
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