The Siren Site and the Long Transition from Archaic to Late Prehistoric Lifeways on the Eastern Edwards Plateau of Central Texas

On behalf of the Texas Department of Transportation (TxDOT), SWCA Environmental Consultants (SWCA) conducted testing and data recovery investigations at the Siren site (41WM1126), a prehistoric multi-component site in the Interstate Highway 35 right-of-way along the South Fork of the San Gabriel River in Williamson County, Texas. The work was done to fulfill TxDOT’s compliance obligations under the National Historic Preservation Act and the Antiquities Code of Texas. The testing investigations were conducted under Antiquities Permit 3834, and the subsequent data recovery was under Permit 3938. Kevin Miller served as Principal Investigator on both permits. Though the site extends far beyond the area of potential effects both horizontally and vertically, the investigations focused on Late Archaic and Late Prehistoric components within a relatively limited area that would be subject to project impacts. The investigations were conducted in February 2006. The investigations identified five isolable components that were intermittently laid down from approximately 2600 to 900 years ago. A substantial Late Prehistoric Austin phase occupation is represented by Scallorn projectile points, stone tools, burned rock, faunal materials, and radiocarbon dates from cooking features. The component feature assemblage includes a cluster of discrete, well-preserved burned rock features that range from small fire-cracked rock concentrations to a large, slab-lined feature that dominates the cluster. The underlying components include four cultural strata representing a series of phases in the final millennium or so of the long Archaic period. These components span approximately 2600 to 1500 b.p., though earlier, deeply buried components were also noted on the site. These deeper deposits were not the focus of the investigations, however, since they would not be affected by the project. The Archaic components revealed a suite of small side-notched dart points such as Ensor, Fairland, and Frio, as well as many earlier broad-bladed styles such as Castroville, Montell, Marshall, and Pedernales. These robust components contained numerous burned rock features of varying size and function, abundant tools, well-preserved faunal materials, macrobotanical remains including geophytes from several earth ovens, and a large suite of radiocarbon dates. The features include an incipient burned rock midden, burned rock clusters, a debitage reduction area, a biface cache, slab-lined hearths, basin-shaped hearths, and small circular hearths. The distributions of artifacts and features within the Archaic components across the excavation blocks showed significant variations. These differences reflect sequential components that provide a view of diachronic trends in technology, subsistence, economy, and a suite of other behaviors and activities during the long transition from Archaic to Late Prehistoric adaptations. As previously determined by the testing excavations and further substantiated by the data recovery investigations, the Siren site, most notably the Late Archaic and Late Prehistoric components, is eligible for the National Register of Historic Places under Criterion D, 36 CFR 60.4, and eligible for State Archeological Landmark designation under Criteria 1 and 2 of the Rules of Practice and Procedure for the Antiquities Code of Texas, 13 TAC 26.8. The excavations and subsequent analysis have mitigated the adverse effects of the bridge construction by recovering the vast majority of the affected components within the area of potential effect. No further archaeological work is recommended. Portions of the site outside the area of potential effects have not been fully evaluated, and any future impacts beyond the mitigated areas warrant further assessment