Fiber-tempered potsherds recovered from three sites of the Nebo Hill phase in western Missouri and eastern Kansas date to between 4550 and 3550 radiocarbon years (2600-1600 BC) and represent the earliest dated vessels in the midwest. The occurence of fiber-tempered pottery at this time period and this far north and west of the traditionally-defined southeastern hearth for such wares requires a major reappraisal of the assumed distribution and antiquity of late Archaic ceramics in eastern North America. This report describes the ceramic sherds from the Nebo Hill type site in terms of their method of manufacture and probable use, and identifies factors influencing their survival and preservation in the middle-latitude lowlands. It is proposed that the temperate latitude distribution pattern of shallowly-buried, fiber-tempered potsherds is shaped primarily by the variables of time, ambient moisture and temperature, and ware porosity, and is not necessarily isomorphic with the prehistoric distribution of fiber-tempered vessels.