The timing of Mississippian-period occupations in the North Central Hills physiographic region of Mississippi has been debated. Some researchers believe they occurred in conjunction with Late Woodland period occupations during the Early Mississippian period, while others assert they were later, in either the Late Mississippian or early Protohistoric periods. A program of systematic shovel testing, excavation and frequency seriation was used to delineate Mississippian-period occupations and test the cultural lineage between them and Late Woodland period occupations at nine sites on the Ackerman Unit of the Tombigbee National Forest.

This study considers the chemical alteration of archaeological freshwater shell above the water table at Lyon's Bluff, located in east-central Mississippi, changes in trace element concentrations between unfired and fired shell, and the effect bacteria have on archaeological freshwater shell. Thin-section petrography, X-ray diffraction, cathodoluminescence, and scanning electron microscopy were conducted on archaeological shell from four layers from Unit 20N20W, with a depth of 80 cm spanning 450 years. ICP-MS analysis was also conducted on a modern freshwater shell. Results of the microscopy indicate pristine crystal structure. ICP-MS data show that certain trace elements within the shell maintain their concentration after firing at 500°C. The broader implications are: 1) that diagenetic alteration does not hinder chemical sourcing of shell at Lyon’s Bluff, and 2) that certain trace elements are more reliable than others, namely Sr2+, Al2+, Ba2+, and Mn2+, when conducting provenance studies on shell temper.