Thus, in general, we seem to have a grouping of stocks around geographical nuclei and this raises the question as to the nature of this larger group. Is this somewhat vague, but still definite, group of stocks to be considered as of the same sort as the strictly genetic cluster within a single stock? If the answer proves to be negative, then we must seek for some external causes contributing to this result; but, if positive, then the stocks forming such a group are themselves of common origin or descent. Between these two positions, the anthropologists of the United States are about equally divided. If we examine the case upon its gross merits, there appears no discernible difference between the kinds of similarities by which stock affiliations are determined and those making these geographical groups. It is merely a matter of degree. That being the case, the probabilities favor the genetic interpretation. On the other hand, very vague similarities may be possible as the result of mere social contact, in which case the genetic relation could only apply to one or two elements of the language. However, speculation upon these points is futile, and we may conclude by noting that along this line the greatest advances in future linguistic researches are to be expected.
The best illustration of the above is found in the investigations of Californian languages by Kroeber and Dixon,[1] to which we several times referred. In Fig. 88 we see the positions of the original twenty-two stocks identified by Powell. Later, Kroeber and Dixon[2] discovered three large morphological groups for these stocks as indicated by the shadings on the map. Recently,[3] these investigators have become convinced that these larger groups represent single stocks, two of which are not found elsewhere (Hokan and Penutian), while the third is a member of the Algonquian stock. While other linguists have not yet accepted this genetic interpretation of the observed grouping, the facts of similarity are not in dispute. In our discussion of the Californian culture area we noted a central group of tribes possessing the most typical culture (p. 212), and we now see that these are almost exclusively members of the Hokan group. Thus, if the genetic relationship of these Powell stocks is denied, we must assume
