Page:Popular Science Monthly Volume 48.djvu/36

26 connection between the Glacial period and the flood, and the probable reason why no tradition has descended to us of the former; first, because man was born during its epoch and was formed by it and accustomed to it, and living in the one temperate zone on the equator saw nothing strange in his surroundings, and, secondly, because the only change that man saw was the sudden accumulation of waters descending from the earthquake-riven and colder portions of his then unexplored globe.

Thus, man's remains have been found with those of the mammoth—a mammal of the warm, subtropical Pliocene period, that lived on into the cold Pleistocene epoch. Probably his origin was previous to that of man; but man may not have appeared until the end of the Pliocene period and the commencement of the cold, which, in all likelihood, gradually and surely came on, as the interior of the globe shrank farther and farther away from contact with the easily chilled outer crust, which it left to fields of ice bordering a narrow temperate zone; the ice reaching from the north pole as far south possibly as 50° north of the equator, and from the south pole as far north as 40° south of the equator; thus the present temperate zones became arctic, and the tropical zone became almost unvaryingly temperate. Man probably in his first ages had spread far and wide north and south of the equator, but not so far as at present we find ourselves; he had been gradually driven back by the advancing cold, yet so slowly that the change did not make itself noticeable to him, and as his civilization advanced to the time when he began to build and to establish great cities he found himself settled near the equator, even further south than ancient Thebes, and probably where the great deserts of Arabia, Nubia, and those of the Sahara stretch their vast plains of sands, and perchance now cover works even older than the stepped pyramid of Ata. However long, therefore, these periods of change may have been, it seems very probable that man first appeared in a fresh, temperate climate, the only proof of which is that he has several times been found with the remains of the mammoth, an animal that outlived the primal warm periods. Probably no preglacial period existed for man. As for the length of time that must have elapsed between the first appearance of vegetation upon the earth until the time that the climax of the Glacial period arrived, when the flood took place, ten thousand years need not be too much. Midst the surroundings of that Glacial period, however, man's remains have been found, but not in those of the preglacial ages that lead back to the ichthyosaurus, plesiosaurus, and other monsters of the deep, or of the age of gigantic flora, huge pine trees, and enormous ferns.

If the flood, then, as some have calculated, was only five or six thousand years ago, then the coldest period of the Glacial age can