Archaeological excavations conducted at the Bayou Gulch site in 1979 by the Colorado Department of Highways Archaeological Unit revealed a prehistoric, intermittently occupied, open campsite. The site is located in the Plains-FoothHIs transition zone at the con fluence of Cherry and Bayju creeks (south of Denver) on the extreme western perimeter of the Central Plains culture subarea. Before sherd locations were pinpointed stratigraph ically, there was an attribute analysis of the pottery, with sherds arranged into categories on the basis of wall thickness and cord impressions. The resulting groups included thin-walled, clearly and finely cordmarked pot tery, and thick-walled, coarsly cordmarked ceramics with obliterated varieties. The sherds were compared with whole and partial vessels from documented sites in Col orado, Kansas, Nebraska, and Wyoming in order to deter mine the relationship of the Bayou Gulch ceramics to recognized Plains pottery types. Finally, the sherd types were considered in the context of their exact stratigraphic positions and relationship to features and radiocarbon ages. These comparative analyses clarified the chrono logical positioning of the pottery. The results of this study suggest that the ceramic remains from Bayou Gulch are affiliated with the terminal Plains Woodland, radiocarbon dated between A.D. 900 and 1100. INTRODUCTION Pottery manufacture reached the inhab itants of the western High Plains at the begin ning of the Christian era (Wood 1967:594). Sears (1948:122) and Willey (1966:267) have defined the transition from the Archaic to the cultural tradition by the appear ance of cordmarked pottery in the latter. Archaeological manifestations in the western Plains exhibiting this early ceramic develop ment have been called Woodland in recog nition of similarities with Middle period components in the Missouri River area, which in turn are closely related to the cultural history of the eastern Woodlands (Willey 1966:311). The basic temporal trend observed in Plains ceramics involves the replacement of earlier, cord-roughened vessels with smoothed-surface or thong-wrapped, paddle marked types (Wedel 1961:168-182). The stratigraphically earlier vessels had elongated bodies, conoidal bases, and direct or slightly