A re-evaluation of late prehistoric and archaic chronology in the Rio Grande Delta of south Texas

Radiocarbon assays, biochemical and bioarcheological analyses of burials from South Texas are presented in this dissertation. Excavated during the 1940’s, 1950’s and 1960’s, the excavated burials from the Ayala Site in Hidalgo County and the Floyd Morris Site in Cameron County contain a wealth of new information concerning what has been referred to as the Brownsville Complex. Radiocarbon assays obtained by the author suggest the Late Prehistoric temporal framework previously ascribed to the Brownsville Complex is inadequate, in that burials containing hallmarks of the Brownsville Complex are found to date to the Middle and Late Archaic periods. Comparisons between these cemeteries and other Archaic cemeteries and burials in Texas suggest that a regional mortuary tradition may have developed in the Rio Grande Delta in concert with and sharing commonalities with the flurry of mortuary activity on the Texas Coast during the same period. In addition, a combination of carbon and nitrogen values from the two sites add to the sparse subsistence data from the region, and suggest a combination of riverine and coastal subsistence adaptations. The term “Brownsville Complex” is inadequate to describe the time depth revealed for what appears to be a unique Rio Grande adaptation, and it is hoped that the data compiled and presented here will be used and expounded to address research issues in the Rio Grande Delta. Additional information concerning the cultural chronology, subsistence patterns, and evidence of trade with other regions of Texas and Mexico will be key to redefining the archaeology of the region.