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):
The conclusion is that the culture of the Wind River Shoshoni exhibits a strange conflicting situation. It belongs neither to the foodgatherers of the west nor to the hunting cultures of the east—it is something sui generis. To ascribe it to anyone of its bordering cultures is to lose the dynamic aspect of the cultural evolution of the tribe.
He thus sees the eastern Shoshone as synthesizers and transformers of cultural material derived from both eastern and western sources; their culture is a blend of the two, but it is not a simple compound of them. The present work does not attempt to answer the question of the relation of the content of the culture of the equestrian Shoshone to that of peoples to the east and west but will focus attention upon social structure. And it will do this, not through a consideration of outside influences upon the Shoshone, but by analysis of their social institutions and the relationship of them to economic life.
Our note on the length of involvement of the Shoshone in Plains Indian culture leads us to inquire briefly into the time depth of this culture and its relation to the expansion of the American frontier. Although it is quite probable that certain cultural traits and social institutions characteristic of later Plains life had antecedents in the pre-equestrian period, the possession of herds of horses was the basis of later patterns of amalgamation and incipient stratification. It also had much to do with the intensification of warfare. The horse, according to Haines (1938), spread from the Spanish Southwest to more northerly areas along both sides of the Rocky Mountains. Its diffusion along the western slope of the range was presumably the more rapid, and Haines gives evidence indicating that the Shoshone had horses about 1690 to 1700, at which time the animal was found no farther north than the Arkansas-Oklahoma border in the Plains (ibid., p. 435). From this Shoshone center, the use of the horse spread north to the Columbia River, the Plateau, and the northern plains. It followed an independent route north from Texas to the Missouri River and the fringe of the woodlands.
Their early acquisition of the horse may have allowed the Shoshone to penetrate the northern plains as far as Saskatchewan in the early eighteenth century, for David Thompson's journals tell of warfare between the Blackfoot and Shoshone in that region at some time in the 1720's or early 1730's (Tyrell, 1916, pp. 328 ff.). The northerly extension of the Shoshone in the early horse period, and perhaps before, has been discussed and generally accepted by many students of the area (cf. Wissler, 1910, p. 17; Shimkin, 1939, p. 22; Ewers, 1955, pp. 16-17; Hultkrantz, 1958, p. 150). There is little information on Shoshone population movements between this date and the journey of Lewis and Clark. In 1742 the de la Vérendrye brothers undertook an expedition into the northern plains of the United States and reported upon the ferocity of a people known to them as the "Gens du Serpent," presumably the Snake, or Shoshone. De la Vérendrye wrote of these people (Margry, 1888, p. 601):
No nation is their friend. We are told that in 1741 they entirely laid waste to seventeen villages, killed all the men and old women, made slaves of the young women and traded them to the sea for horses and merchandise.
The Gens du Serpent are not precisely located, but the explorers were told by the "Gens de Chevaux" that they lie in the path to the western sea. Later, a "Gens d'Arc" chief invited them to join in an expedition against the Gens du Serpent on "the slopes of the great mountains that are near the sea" (p. 603). They later found an abandoned enemy village near the mountains, but returned without further contact. Shimkin believes that this village was in the Black Hills (Shimkin, 1939, p. 22), but the journals are most hazy on geography. The previously cited information from the Gens d'Arc chief suggests that the group was located farther west, in the vicinity of the Rocky Mountains. It must be remembered, however, that there has been considerable contention among historians, not only over the route of the de la Vérendrye brothers, but over the identification of the Gens du Serpent. L. J. Burpee has reviewed (1927, pp. 13-23) various conflicting interpretations of the journals, and the matter can hardly be considered settled.
By this period, the Blackfoot and other northern tribes were already armed with guns (see Ewers, 1955, p. 16; Haines, 1938, p. 435), obtained through commerce with the French and English traders of Canada. They had also become mounted, and it may be surmised that the Shoshone lost their equestrian advantage at almost the same time that their enemies acquired guns. Thus the Shoshone retreat from the Canadian plains may well have begun before 1750, as Thompson's narrative indeed suggests (Tyrrell, 1916, pp. 334 ff.). The process was certainly complete by 1805, when Lewis and Clark found the Lemhi River Shoshone hiding in the fastnesses west of the Bitterroot Range and lamenting their loss of the Missouri River buffalo country to better-armed groups. The Shoshone, once masters of the northern Plains, had fallen upon bad times. They complained to the explorers that they were forced to reside on the waters of the Columbia River from the middle of May to the first of September for fear of the Blackfoot, who had driven them out of the buffalo country with firearms (Lewis and Clark, 1904-06, 2:373). Their forays into the Missouri drainage were made only in strength with other Shoshone and their Flathead allies (2:374). The Shoshone apparently were able to utilize areas of Montana adjacent to the Bitterroot Range, for signs of their root-digging activities were seen on the Beaverhead River (2:329-334). This pattern of transmontane buffalo hunting described by Lewis and Clark remained essentially the same until its final end after the establishment of the reservation, and will be described in detail later in this work.
It is possible now to discern three periods in this early phase of Shoshone history. The first, the footgoing period, is unknown, and little can be inferred of Shoshone location and movements. The second period is characterized by the acquisition of the horse, and we would conjecture that a good deal of territorial expansion took place after that time. The Comanche differentiated from the main Shoshone group at the beginning of the eighteenth century. Although the Comanche maintained communication with their northern colinguists, the territories of the two groups were not contiguous by the end of the century, and their histories followed separate courses. The extension of the Shoshone into the northern Plains may possibly have predated the acquisition of the horse, for it seems quite likely that they occupied fairly extensive areas east of the Rockies in the footgoing period. But, on the other hand, it seems unlikely that in the period immediately preceding 1700, the most probable date for the acquisition of the horse, they extended from the Arkansas River on the south to the Bow River in Saskatchewan. This would be especially unlikely if later distribution of Shoshone-speakers in the Basin-Plateau was substantially the same in the earlier period also. We would conjecture, then, that equestrian life gave the Shoshone the mobility to extend into the Canadian buffalo grounds but that they were pushed back beyond the divide well before 1800. As Shimkin has noted, the ravages of smallpox and the resulting decline of population probably contributed to their territorial shrinkage (Shimkin, 1939, p. 22).