Lithic Raw Materials in the Lower Rio Grande Valley, South Texas and Northeast Mexico

ABSTRACT

Analysis of 976 lithic artifacts from twelve museum and private collections in the Lower Rio Grande Valley revealed a preference for seven rock types. Sixty nine percent of all tools were made from gravel chert, which is locally the most abundant rock type on the Frio and Goliad Formations, as well as on the gravels of the Rio Grande. Representing less than 10% each were, the local El Sauz Chert, a black banded metamorphic rock, volcanic rocks, agates, silicified wood, limestone and black chert. Variations in the relative proportion of each rock type are observed by location, suggesting a tendency to use other suitable rocks that were locally available. Contrary to what has been suggested an abundance of lithic resources were available to stone tool makers in the Lower Rio Grande Valley. This study underscores the value of working with collectors in regions where little archaeological research has been conducted.

KEYWORDS:

• Lower Rio Grande Valley
• El Sauz Chert
• private collections
• south Texas

Acknowledgements

Support for this research was made possible by the UTRGV Community Historical Archaeology Project with Schools (CHAPS) Program in conjunction with the Houston Endowment for Civic Engagement. The authors thank the Museum of South Texas History, the UTRGV Department of Anthropology, Danielle Sekula, Victor Paiz, Thomas Eubanks, Daniel Ramirez, Joe Swindle, Joel Shiner, Eugene Pilarczyk, Wanda Bouch, Daniel Boultinghouse, Tom Aderhold, W. Francey for access to their collections. We also wish to thank Dr. James Hinthorne for his careful editing of this manuscript and his unwavering support of this study over the past four years.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Brandi Reger, completed a BA in Multidisciplinary Studies (Geology, Archaeology and Statistics) University of Texas Rio Grande Valley, in 2019. Main areas of research are stone tool use and variability in south Texas, geochemical fingerprinting of raw materials, and exploring ways to apply statistically inspired methods to archaeological datasets.

Juan L. González is an Associate Professor, at the School of Earth, Environmental, and Marine Sciences, University of Texas, Rio Grande Valley. He has a Ph.D. in Geology from Tulane University. His research focusses on human transformation of the landscape inprehistory, Holocene paleoclimate and sea level change, the Quaternary Geology of the Rio Grande Valley. Current projects include constructing a paleosea-level curve for Caribbean Colombia, assessing the environmental impacts caused by the emergence of a large-scalestone tool industry on the Caribbean Lowlands of Colombia, and studying the geologic history and human occupation of the South Texas Sand Sheet.

Russell K. Skowronek is Professor of Anthropology & History at the University of Texas Rio Grande Valley. He has a Ph.D. in Anthropology from Michigan State University and a M.A. in History from Florida State University. His research focuses on the archaeology and ethnohistory of prehistoric Texas and California, and the Spanish colonial empire. Professor Skowronek is the director of the Community Historical Archaeology Project with Schools (CHAPS) Program at the University of Texas Rio Grande Valley where he also serves as an Associate Dean in the College of Liberal Arts. Professor Skowronek has held the Houston Endowment Chair for Civic Engagement since 2017.