Of a different sort but equally meritorious is Lowie's historical analysis of societies among the various tribal groups in the Plains Area.[1] The full reports available for practically all the many Plains tribes make it obvious that one general system of societies was diffused throughout the area. By a close analysis of these data it is possible to show some of the older forms of these organizations, approximately where they arose, and in what direction they were diffused. Incidentally, close former historical contacts were revealed for some tribes now rather widely separated.
Thus, we see, that by working backward from the historic period or, as in the exceptional case of the Maya, from a fixed date, it is possible by these methods to separate the older elements of culture from those of relatively recent origin. Looking back over these typical studies we see that the general method is the same whether the subject be in art, industries, or social organization. In the main, it first analyzes the culture trait-complexes and then by comparative reasoning arranges them in time sequences. Practically every skilled field-investigator in the New World faces problems of this sort; but the method is at its best only when we deal with traits having wide continuous distributions, for unless we can balance the trait variations in one group of people against those in a neighboring group, little can be expected.
Aside from these more engaging problems there are opportunities for the study of trait origin by direct methods. Of these Mooney's Ghost Dance Religion[2] is a fine example. In such cases the problem is, on the whole, directly historical, based upon documentary and personal testimony. It is to be regretted that more attention is not given to such problems because it is only in them that we shall get actual cases of culture movements to serve as check data in the development of inferential chronologies.
In concluding this brief survey of the as yet undeveloped chronology of New World culture, we note one or two points of general interest. In the main, the stratigraphic chronologies have been determined by pottery alone, suggesting that the ceramic art as a whole should receive the very closest
