The earth of this continent shows us that before the Indians there has been a people whom we call Mound-builders—that is, mounds were thrown up here by men whose bones we find in them, lying among rough tools and utensils, and after the mounds we name the race, who, perhaps, were not a different people from the Indians. But for these mounds we would not know of the men who built them. They are mentioned in no history, human or divine. What was there before the Mound-builder?... When we come to the question as to the descendants of this early North American man, we cannot avoid studying for a moment the movements or migrations of man over the surface of the earth generally. I think we may divide his migrations into two main classes from their motives: a primitive migration, (and) a culture migration...