Carbon and nitrogen stable isotope ratios in bone collagen — a chemical record of what individuals ate over the years their bones were being built and remodeled — showed that the earliest populations at the site had diets heavy in aquatic protein.

Fish.

Freshwater mussels.

Resources from the river.

This dietary signature decreased in later populations at the site, suggesting that aquatic resource use declined as the Archaic period progressed — perhaps as the river’s productivity changed, perhaps as population pressure increased and groups diversified their dietary strategies.

The shift in diet encoded in their bones tells a story of adaptation: these were not static populations frozen in time.

They were people responding to changing conditions, shifting their strategies as the environment around them changed.