112 BUREAU OF AMERICAN ETHNOLOGY [Bull. 176 



to in older documents — i.e., has become reestablished or has expanded 

 since the period of original use of the site. It is probable that when 

 the site was in use, land lying between it and the river would have 

 been cleared, as a security measure, as is suggested by the statement 

 of Wandel, cited above (p. 95), to facilitate transshipment of goods 

 by steamboat, and as a result of heavy demands by the trading post 

 upon local resources for fuel and construction materials. 



Changes such as these, in the character of the natural resources 

 of the immediate area following the period of the trading post, may 

 be inferred, prior to the agricultural use of these lands, beginning 

 about the year 1892. The needs of a trading post, in fuel and construc- 

 tion materials, would materially have altered the timber cover of the 

 immediate area, whereas soils and grasses would probably have been 

 affected to only a slight extent, only in the immediate vicinity of the 

 post, and only accidentally, rather than systematically. In the ex- 

 cavation data there are, for example, only slight hints of the use of 

 horses or cattle, or of provisions for stabling them, from which one 

 might infer the degree of use of grazing lands in the immediate neigh- 

 borhood. Such animals were, of course, essential to the operation of 

 such a post, but there are surprisingly few traces, in specimen materials 

 recovered, to document the fact. Cultivation of the soil, furthermore, 

 while no doubt practiced here during the period in question, may 

 also have been of minor importance — perhaps little beyond small 

 kitchen gardens, of which no evidence has been found. 



AKCHEOLOGICAL EVIDENCE OBTAINED 



Before proceeding to an account of new data obtained in excava- 

 tion at Site 39ST217, it seems well to describe tlie methods employed 

 in obtaining the data. Available historical documentation, maps, and 

 aerial photographs had been studied with care before the immediate 

 area was visited in May 1956. Two series of aerial mosaic photo- 

 graphs were used — that of the former Agricultural Adjustment Ad- 

 ministration, U.S. Department of Agriculture, of 1938, and that 

 of the Corps of Engineers, U.S. Ai-my, of 1946. (Parts of the first 

 series are in the files of the Missouri Basin Project; the later series 

 was consulted in the Oahe Area Office, C.E. The latter series of 

 photographs was the basis for the engraved maps of the IMissouri 

 River from Gavins Point, near Yankton, S. Dak., to Stanton, N. 

 Dak., prepared by stereophotogrammetric methods in 1947. These 

 engraved maps are also in the files of the Missouri Basin Project.) 



Of these two series of aerial photographs, the former, made during 

 the dry cycle of the 1930's, appeared to be the more helpful for 

 present purposes. Examination of the sheet of the series covering this 

 site (AAA-BOK-3/56-June 2, 1938) suggested that the site of Fort 



