At the opening of the preceding chapter we made some allusions to the supposed antiquity of the Red Indian, a subject of growing archæological significance, though as yet it affords us rather unsatisfactory evidence, scientifically considered, relative to the problem of man’s antiquity on this continent. Quite different, however, is the estimate which we place on data left us by the people of the mounds. The question of the antiquity of the Mound-builders is one which cannot be accurately determined; no chronometric scale can be applied to the uncertain record which they have left behind them. Their history is a sealed book, and the approximate date of their first occupancy of the Mississippi Basin is as uncertain as the period of man’s origin. However, certain data present themselves for our consideration which lead us to conclude that a few thousand years, three or four perhaps, and possibly even less time, is all that is required in which to account for their growth into a nation and the moderate advancement which they made toward civilization. As to when the Mound-builders left this country, is another question, and can be approximated more closely. It is a well-known fact that no tradition was ever found among the Indians as to the origin or the purpose for which the mounds were constructed. They described them as having been found by their ancestors in the same condition in which we now see them, and clothed, if not with the same, at least with a growth of vegetation similar to that which covers them to-day. It is true the Iroquois, who are supposed to have reached the lake regions and the Ohio Valley some time previous to the Algonquins, had certain vague traditions of a people whom they called the “Allighewi;” but there seems to be nothing in those indefinite allusions which would associate that unknown people with the mounds. Still, Indian tradition is nearly valueless in determining this question, since any fact, however grave, was soon forgotten by a people so savage and unsettled. The tribes of the lake region, says Dr. Lapham in his _Antiquities_, so soon forgot the visit of the Jesuit Fathers that their descendants a few generations later had no tradition of the event. The same is true of the Indians of the Mississippi Valley with reference to De Soto’s expedition, “which must,” remarks Dr. Foster, “have impressed their ancestors with dread at the sight of horses ridden by men, and the sound of fire-arms, which they must have likened to thunder. Sir John Lubbock states that the New Zealanders at the time of Captain Cook’s visit had forgotten altogether Tasman’s visit, made less than one hundred and thirty years before.”[86] Another argument for the construction of the mounds at a remote period, and which is certainly of little more value than Indian tradition, is that which supposes the Mound-builders to have erected works on the lowest of the river terraces existing at the time of their occupancy of the country.