TxDOT - 41MS78

On behalf of the Texas Department of Transportation, SWCA Environmental Consultants conducted data recovery investigations of the Llano Crossing site (41MS78) as part of the Ranch-to-Market Road 1871 bridge replacement project (project) (CSJ: 1753-01-017) in Mason County, Texas. Conducted from February 6 to March 21, 2019, the field investigations revealed a deeply stratified multicomponent prehistoric site that includes sparse but isolable occupations of multiple intervals from Paleoindian through Late Prehistoric times. To mitigate project-related effects to the site, investigations were conducted in compliance with Section 106 of the National Historic Preservation Act (54 U.S. Code 306108) and the Antiquities Code of Texas (9 Natural Resources Code, Chapter 191). The site was previously determined eligible for the National Register of Historic Places (NRHP) (36 Code of Federal Regulations 60.4) and for designation as a State Antiquities Landmark (SAL) (13 Texas Administrative Code 26.8, 26.12). Kevin Miller served as Principal Investigator under Texas Antiquities Permit No. 8723. Integrated Environmental Solutions, Hicks & Company, geoarcheologist Dr. Charles Frederick, and numerous specialized analysts contributed to the analyses and field investigations.

The Llano Crossing site includes Paleoindian, Early, Middle, and Late Archaic, and subtle Late Prehistoric components buried in high, deep terraces of the Llano River overlooking a natural historic river crossing, a strategic position that may have been the reason for its selection as an occupational locus through the millennia. The investigations revealed material assemblages consisting of diffusely scattered burned rock, debitage, and lithic tools, which were predominantly recovered from deep depositional strata in the gradually aggrading terraces that formed throughout the Holocene. The conditions were not conducive to preservation of organics within the project’s area of potential effects (APE). However, isolable concentrations of artifacts were identified associated with several intact features. In the few components where such patterns were identified, hints at archeological surfaces, patterns, or site structure could be discerned. Since radiocarbon dating was only possible in a few areas with charcoal preservation, optically stimulated luminescence and temporally diagnostic artifacts provided important data for developing the chronostratigraphy. Although the investigations identified some intact areas, poor floral and faunal preservation, sparse and unsubstantial material assemblages, and highway construction disturbances imposed interpretive limitations. Nevertheless, the site yielded important comparative information on regional patterns through time. Therefore, the investigations support the NRHP and SAL eligibility of the site under Criterion D. The site extends beyond the APE and these unevaluated areas have a potential for substantial intact deposits.