Ohio's Adena culture represents a turning point in state history. Situated between the nomadic hunting and gathering cultures of the Archaic period and the more settled farming cultures of the later Woodland period, the Adena culture represented the dawn of a new way of life for Ohio's ancient people.
Archaeologists now are fleshing out the details of the daily lives of Ohio's first farmers, who were known mostly for their mortuary and ritual sites, such as Chillicothe's Adena Mound, for which the culture is named.
I should give this thing a read. It should give a good set of data on a transition to agriculture that is much more gradual than is often the case.