Refit and Oxygen Isotope Analysis of Freshwater Mussel Shells from the Tillar Farms Site (3DR30), Southeast Arkansas

We investigate the link between the consumption of foodstuffs, excavation of a large pit, and disposal of waste at the Tillar Farms site (3DR30), southeast Arkansas, using refit and oxygen isotope analyses of well-preserved freshwater mussel shells from Feature 1. Only 0.13% of 7,408 valves analyzed were unidentifiable to species.The refit analysis produced 460 refits across 23 species and strongly indicates that the shell midden represents a single episode of shellfish gathering, consumption, and discard. Oxygen isotope analysis of five randomly selected shells are used as a test of the refit results. delta O-18 values from the five archaeological shells are compared to modern control samples of live-collected specimens from Bayou Bartholomew in winter of 2011. Refit analysis suggests the accumulation of mussel shells occurred quickly, likely as a result of one collection, consumption, and discard event. delta O-18 values suggest this activity took place during a single winter season.