We need only recall how strong are the evidences on this point. Nearly all European writers admit at least one such mild interval, and though not wanting evidence of such a period in America, our geologists are much less confident of its occurrence.
But from that point the eccentricity again increased. So when the long flight of years again brought secular Winter to the Northern Hemisphere, the glaciers would speedily appear, and as eccentricity was again high, they would again hold the country in their grasp. Fifty thousand years later, or one hundred thousand years ago, it passed its turning point again; eighty thousand years ago, it became so small that it probably ceased to effect the climate. Since then it has not been very large. Twenty-five thousand years ago it was less than it is now, but it is again growing smaller. According to this theory, then, the Glacial Age commenced about two hundred and twenty thousand years ago. It continued, with one interruption of mild climate, for one hundred and forty thousand years, and finally passed away eighty thousand years ago.
What shall we say to these results? If true, what a wonderful antiquity is here unfolded for the human race, and what a wonderful lapse of time is included in what is known as the Paleolithic Age! How strikingly does it impress upon our minds the slow development of man! Is such an antiquity for man in itself absurd? We know no reason for such a conclusion. Our most eminent scholars nowhere set a limit to the time of man’s first appearance. It is true, many of them do not think the evidence strong enough to affirm such an antiquity, but there are no bounds given beyond which we may not pass.
Without investigation some might reject the idea that man could have lived on the earth one hundred thousand years in a state of Savagism. If endowed with the attributes of humanity, it may seem to them that he would long before that time have achieved civilization. Such persons do not consider the lowliness of his first condition and the extreme slowness with which progress must have gone forward. On this point the geologists and the sociologists agree. Says Mr. Geikie: “The time which has elapsed from the close of the Paleolithic Age, even up to the present day, can not for a moment compare with the aeons during which the men of the old stone period occupied Europe.” And on this subject Mr. Morgan says: “It is a conclusion of deep importance in ethnology that the experience of mankind in Savagery was longer in duration than all their subsequent experience, and that the period of Civilization covers but a fragment of the life of the race.”32 The time itself, which seems to us so long, is but a brief space as compared with the ages nature has manifestly required to work out some of the results we see before us every day. We are sure, but few of our scholars think this too liberal an estimate. All endeavor to impress on our minds that the Glacial Age is an expression covering a very long period of time.