The Great Bend aspect is the designation for proto-historic Wichita sites in central and southern Kansas, dating from A.D. 1425 to 1700. The origins of the Great Bend aspect have not been studied in depth previously, but comparisons with the earlier Central Plain mosaic suggest that the latter was not directly ancestral to Great Bend. Patterns of tool-stone acquisition, ceramic vessel forms and surface treatments, and formal stone tool types all differ. This research tracks changes in material culture as the Great Bend aspect developed. This research employs stacked outline comparative analysis of lithic assemblages from sites of the Pratt phase, the Zyba site, an early Little River site in Rice County, and early hunting camps along the Walnut River. These sites appear to date immediately before the emergence of Great Bend and after the disappearance of the Central Plain mosaic. The sites examined all appear to be ancestral to the Great Bend aspect and are more similar to the Odessa phase than to the Central Plains mosaic.