Human interaction with riverine ecology is an important component of recent modelling of agricultural origins in eastern North America. Recent research on the ancestral Ontario Iroquoian Princess Point Complex (A.C. 500--900) in south-central Ontario, Canada, demonstrates that the floodplain of the Grand River was an important setting for initial maize production in this region. This paper presents a case study of an archaeological occupation in relation to its floodplain setting during the transition from hunting and gathering to agriculture. Previous interpretation of the Princess Point occupation of the lower Grand River Valley suggested that maize cultivation was grafted onto a Middle Woodland pattern of seasonally scheduled foraging. In particular, the old model proposed that floodplain disruption by substantial annual flooding and ice rafting limited use of the floodplain; exploitation of floodplain habitats was limited to the late spring, summer, and early autumn when maize cultivation could be conducted.
Between 1993 and 1995, the Grand Banks site (AfGx-3), situated on a lateral bar in the floodplain of the Grand River, was the subject of archaeological and geomorphological investigation of stratigraphy and site formation. The stratigraphy of the bar shows that its development was characterized by variable sedimentation rates throughout the Holocene. The rates were affected by changes in Lake Erie water levels and possibly by climate shifts, both of which broadly coincide with events interpreted from the Grand Banks site stratigraphy. The bar surface was, contrary to earlier interpretations, relatively stable during two periods, one being the crucial period from A.C. 500--900 when maize cultivation was introduced. Explanations of agricultural origins in eastern North America need to take the complexity of floodplain histories into account.