Despite the continuity of language between the Shoshone and Bannock of Wyoming and Idaho and the simple Basin people to the west, it has long been obvious that the first two were culturally marginal to the Plains. Wissler listed the Northern and Eastern Shoshone and the Bannock among the Plains tribes, but he excluded them from his category of groups typical of the area and described them as "intermediate" (Wissler, 1920, pp. 19-20). Kroeber, however, was more aware of the historical recency of Plains culture and described the Idaho Bannock and Shoshone and the Wind River (Eastern) Shoshone as forming "marginal subareas" of the Basin (Kroeber, 1939, p. 53). As such, they are included in his Intermediate and Intermountain Areas. Kroeber noted specifically of the Eastern Shoshone (p. 80): These people, in turn, live in an area which belongs to the Rocky Mountains physiographically, with the Basin vegetationally: it is sagebrush, not grassland. Wind River culture must have been of pretty pure Basin type until the horse came in and they began to take on an overlay of Plains culture. It was about this time, apparently, that the Comanche moved south from them. Shimkin, who made an intensive study of the Eastern Shoshone of the Wind River Reservation, is inclined to emphasize their Plains affiliation (1947_a_, p. 245): Wind River Shoshone culture has been essentially that of the Plains for a good two hundred years; pioneer ethnographers have vastly overemphasized the Basin affiliations. Assuming that this 200-year period dates approximately from the time of Shimkin's field work in 1937-1938, this would extend the Plains cultural position of the Shoshone back to the time at which the Blackfoot were just acquiring horses, a period in which the use of the horse had yet to reach the tribes north and east of the Missouri River (Haines, 1938, pp. 433-435). Although Shimkin rightly states (1939) that the Shoshone were among the earliest mounted buffalo hunters of the northern Plains, it is most questionable whether one can speak of a "Plains culture" at that time, in the sense that the term has been used in culture area classifications. It would seem that the resolution of this problem depends upon the questions of the degree of stability of Plains culture and of the extent to which it is autochthonous to the Plains. Implicit in the discussions above is the attempt to ascertain whether the buffalo-hunting Shoshone were one thing or another--as if the alternatives constituted in themselves homogeneous units--or how much their culture was a blend. Hultkrantz has taken a rather different approach to the problem in his statement (1949, p. 157):