left their earth and bark-covered houses to dwell in tipis. When out after buffalo many of these tribes used a camp and police organization similar to that of the typical Plains group. Other traits, such as the sun dance and sign language, occur but occasionally. The members of the typical group were neither potters nor weavers, but in the eastern group we find some weaving and some pottery, though not so highly developed as in the far east and south. Our eastern Plains group thus stands as an intermediate or transitional culture, between that of the typical buffalo-hunting Indian of the west and the typical sedentary Indian of the Ohio Valley.
In the same way we could show that the tribes to the immediate west are transitional between Plateau and Plains culture, because they have traits common to both.
So far, we have considered culture alone. Anthropologists usually classify people in three ways: language, culture and anatomical characters. Strictly speaking, language should be included in culture, but because of the peculiar difficulties in linguistic research it is more convenient to separate the two. The tribes enumerated in the map speak languages belonging to seven distinct families (Sionan, Algonkin, Caddoan, Kiowan, Shoshonean, Athapascan and Shahaptian) and have more than twenty separate languages. Six of these seven families are found in other culture areas and in some cases widely distributed over the continent. As is well known, there is no apparent correlation between cultures and language, for should we superimpose linguistic and culture area maps there would be no significant correspondence. The same may be said of anatomical type.
We may now consider some of the important problems raised respecting the culture of the Plains Indians. Everybody interested wants to know how and when their culture developed, but all problems of this kind have proved particularly difficult, so that no one can yet say even approximately by what means cultures came about. On the other hand, we have sufficient data from some culture areas of the world to form some idea as to what went on therein within a given period of time.
Several more or less extreme theories have been proposed to account for culture. One is that, in the main, each group of people, independent of every other, worked out and created its own culture. The opposite view is that independent invention is extremely rare, so rare that we may assume all like traits as due to inter-tribal borrowing, or historical contact, until we find evidence to the contrary. The present tendency among American anthropologists is to take the middle ground and stand for empirical methods in that both may be true to a degree and that each culture is to be considered upon its own merits without regard to an initial assumption. To them it seems unnecessary to assume anything as to origin until there is real evidence lending itself to a particu-
