Cultural elements, especially those associated with the horse and with the new mode of life which it made possible, probably came from the region to the southeast, and show a great similarity to the Plains type of culture. How much the Plains culture had influenced the Plateau type before the introduction of the horse, is a question.[448] On the Columbia River, near the mouth of the Yakima, were numerous Indians who were visited by Clark in 1805, but he says that while he saw a few horses, the Indians appeared to make but little use of them. If these were the Yakima Indians there must have been quite a change in their manner of living in the next few years.[449] This agrees very well with the time of the introduction of the horse among the Lower Thompson Indians towards the close of the eighteenth century, according to Teit.[450] All this would tend to show that the horse, while common in the Yakima country, about that time, had not yet affected the earlier customs of the natives. [448] Lewis, p. 179. [449] Lewis, p. 184; Ross, (b), I, p. 19. [450] Teit, (a), p. 257. The early culture throughout the great area of which this is a part, according to Lewis, was of a very simple and undeveloped character, which probably accounts for the rapidity with which eastern types were assimilated when once introduced.[451] [451] Lewis, p. 180. Summing up: the prehistoric culture of the Yakima area resembled that of its recent inhabitants, as it will be remembered was the case in the Thompson River region, the Lower Fraser Valley and the Puget Sound country including the coast from Comox on Vancouver Island to Olympia. As a typical plateau culture, being affiliated with the neighboring cultures to the north, east and south, it presented a sharp contrast to both the present and past cultures of the coast to the west. Compared with other branches of the Plateau culture area it must be considered inferior in complexity to its northern neighbor of the southern interior of British Columbia and also to the adjacent branch near The Dalles to the south. While each of these divisions has been influenced by the others more especially in the past, differentiations due to environment or specific historical conditions lead to local variations without obscuring an essential unity of cultural traits. BIBLIOGRAPHY. BANCROFT, H. H. The Native Races of the Pacific States of North America. 5 volumes. 1874-1882. CATLIN, GEORGE. O-Kee-Pa. A religious Ceremony and other Customs of the Mandans. Philadelphia, 1867. COX, ROSS. Adventures on the Columbia River, etc. New York, 1832. DE SMET, FATHER. Life, Letters and Travels of Father Pierre-Jean De Smet, S.J., 1801-1873. Edited by Chittenden and Richardson. 4 volumes. New York, 1905. DOUGLAS. D. Sketch of a Journey to the Northwestern part of the Continent of North America during the years 1824-27. (Oregon Historical Society Quarterly, 5-6, 1904-05.)