So ends the Yukon and its immediate vicinity. What has been learned?

1. The great and easily navigable river, extending for many hundreds of miles from west to east, could not but have played a material part in the peopling of Alaska, and quite probably in that of the continent, and all human movements along it must have left some material remains. It seems, therefore, a justified inference that the valley of the Yukon harbors human remains of much scientific value.

2. Such remains, judging from the present conditions, were left exclusively along the banks of the river, on the flood-safe elevated platforms of the banks, and especially about the mouths of the tributaries of the Yukon of those times.

3. But the banks and mouths of the past are seldom, if ever, those of to-day. The river, with its currents, storms, and ice pack every spring, is changing from year to year. It is ever cutting and eroding in places, and building bars and islands or covering with flood silts in others. In many stretches no one can be sure where the banks were 500 or 1,000 years ago, not to speak of earlier periods.

4. The banks and islands of to-day, therefore, are for the most part recent formations, in which it would be useless to expect anything very ancient. And there is nothing like the successive ocean beaches at Nome and elsewhere, which would guide exploration.

5. The right hilly side of the river alone seems to offer some hope of locating some more ancient sites and remains; yet it is quite certain that the river ran once far to the left, for all the vast flats on that side are of its construction; so that the more ancient remains of man may lie in that direction. But there everything is, from the point of view of archeology, a practically unexplorable jungle and wilderness, and there is no one there who might make accidental discoveries.

6. It would seem that the best hope for the archeologist along the Yukon, so far as the more ancient remains are concerned, lies along the tributaries of the stream, and that particularly at the old limits of the more recently made lands.

7. Nevertheless the banks of the Yukon as they are now are not wholly barren. Up from Tanana, at the Old Station, probably about Ruby and Nulato, about Kaltag and the Greyling River, at Bonasila, Holy Cross and Ghost Creek, and at the Mountain village, Dog village, Russian Mission, and doubtless a number of other sites, they contain both cultural and skeletal remains that, if recovered, will be invaluable to the anthropological history of these regions.

8. The line of demarcation between the Indians of the Yukon and the Eskimo, outside of language, is indefinite. Traces of old Eskimo admixture are perceptible among the Indians far up the river, and the cultures of the two peoples in many respects merge into each other; while among the Eskimo of the lower river and farther on there are physiognomies that it would be hard to separate from the Indian. Whether all this means simply extensive past mixture, or whether, as would seem, the Alaska Indians as a whole are nearer physically to the Eskimo than are the tribes in the States, remains to be determined. Among the Athapascan Mescalero Apache, who have reached as far south as New Mexico, a somewhat Eskimoid tinge to the face, especially in young women, was by no means very unusual 25 years ago when I studied this tribe. This problem will be touched upon again in this volume.