According to Shoshone tradition, the winter camps of the Eastern Shoshone were in the valley of the Wind River, and their hunting territory extended north to Yellowstone Park and Cody and east to the Big Horn Mountains and beyond South Pass. Little is said by informants of excursions west of the Continental Divide, although historical evidence suggests that this was actually once their principal hunting grounds. In partial support of this contention, Shimkin says (1947_a_, p. 247): "The historical evidence gives some weight to the assumption that in 1835-1840 the Shoshones were mostly west of the Wind River Mountains." He also notes that hostilities between the Shoshone and Crow resulted in the westward withdrawal of the former again in the 1850's (ibid.). In an earlier article Shimkin also stated (1938, p. 415): This [smallpox epidemics in the first half of the 19th century], and probably the increased aggressiveness of other Plains tribes with the spread of firearms as well, led to a recession of the Shoshone and their retreat to the west in the middle of the nineteenth century. A final wave of expansion onto the Plains came with white aid, following the treaty at Fort Bridger, July 3, 1868. While agreeing in part with these conclusions, we would not confine the Shoshone restriction to the territory west of the Continental Divide to such limited periods. The following data suggest, rather, that "the heart of this people's territory," as Shimkin describes the Wind River country, did not extend west of the Wind River Range from at least 1800 until the reservation period and that the Shoshone, while frequently entering the Missouri River drainage, did so only for brief periods and usually in considerable fear of attack. In Washington Irving's account of the Astoria party, one of our earliest reliable sources on the Wyoming Shoshone, the author tells how the Shoshone were pushed out of the Missouri River buffalo country after the North West and Hudson's Bay Companies put firearms in the hands of the Blackfoot (Irving, 1890, p. 197): Thus by degrees the Snakes have become a scattered, broken-spirited, impoverished people, keeping about lonely rivers and mountain streams, and subsisting chiefly upon fish. Such of them as still possess horses and occasionally figure as hunters are called Shoshonies.