Of all geological questions, perhaps that of the Antiquity of Man is the most popular. Nor is it one on which geologists have been rash or hasty in advancing new ideas; quite the reverse: they have lagged behind the evidence. In the “Principles of Geology,” one of the most instructive chapters is that in which the author treats of the progress of Geology. Therein Sir Charles Lyell has shown how the science had been retarded for three hundred years by men's reluctance to admit such a simple and obvious matter as the marine origin of stratified rocks, owing to a fixed idea that the world had come into being a short time since in much the same state as it appears to-day. Yet the illustrious author of the “Principles of Geology” let pass for thirty years the evidence that Man was contemporaneous with the extinct Pleistocene mammalia.