MOORE, Sabrina A., Geology, Texas A&M University Corpus Christi, 2120 Mendocino, Portland, TX 78374, sabrinamoore05@gmail.com, BESONEN, Mark R., Physical and Environmental Sciences, Texas A&M University--Corpus Christi, 6300 Ocean Drive, Unit 5892, HRI 103, Corpus Christi, TX 78412, and DROLET, Robert P., Corpus Christi Museum of Science and History, 1900 N. Chaparral St, Corpus Christi, TX 78401

This study focuses on the petrographic analysis of a prehistoric ceramic collection from the Corpus Christi Museum of Science and History. The pottery is from two neighboring Late Prehistoric , Toyah Phase (AD 1430-1780) ceramic manufacturing sites, 41-NU-54 (also known as Fort Lipantitlán) and 41-SP-220, located in the Lower Nueces River Valley, South Texas. The research was designed to compare vessel manufacture and temper attributes associated with these contemporary settlements. Another goal was to identify and document any technological changes in the Toyah ceramic wares before and during historic contact. This paper describes the methodology used in selecting the sherd sample, preparing the thin sections, and recording the mineralogical and biogenic attributes. Comprehensive evaluation using a petrographic microscope allowed for a quantitative determination of the modal mineralogy of each thin section based on optical aspects of each component. Preliminary results show that ninety five percent of the sherds exhibited little variation in modal mineralogy. Tempers in nineteen of the twenty sherds selected for review were made using local resources such as river sand, bone and clay; however, one sherd in particular had a temper that was different from the others, and it was composed of granitic rock, which is not found in the general area. Further research involving a larger selection of sherds from various sites would add supplementary evidence as to whether further distinctions can be recognized. An intended result is that this study opens up further research opportunities using petrography to correlate the historical and archeological data so that there can be a better understanding of local and regional interactions during this period.