Data Recovery Excavations at the Snakeskin Bluff Site (41GU177), Guadalupe County, Texas

Abstract

On behalf of Central Texas Regional Water Supply Corporation (CTRWSC) and VRRSP Consultants, LLC, SWCA Environmental Consultants (SWCA) conducted archaeological data recovery excavations at multicomponent site 41GU177 (the Snakeskin Bluff Site) within the proposed alignment of the Vista Ridge Regional Water Supply Project (Vista Ridge) in Guadalupe County, Texas. Investigations were conducted in compliance with Section 106 of the National Historic Preservation Act (NHPA) (54 United States Code [USC] 306108) and its implementing regulations (36 Code of Federal Regulations [CFR] 800), in anticipation of a Nationwide Permit 12 from the U.S. Army Corps of Engineers (USACE) in accordance with Section 404 of the Clean Water Act. In addition, the work is subject to compliance with the Antiquities Code of Texas (ACT), as the Vista Ridge Project will be ultimately owned by CTRWSC, a political subdivision of the State of Texas. The Vista Ridge project will involve construction of an approximately 140-mile-long, 60-inch-diameter water pipeline from north-central San Antonio, Bexar County, to Deanville, Burleson County, Texas. The of area of potential effects (APE) for the Phase I survey efforts included the proposed centerline alignment and a 100-foot-wide corridor (50 feet on either side of centerline), as well as temporary and permanent construction easements, and aboveground facilities, such as pump stations and the northern and southern termini sites. Between June 2015 and March 2018 the cultural resources inventory identified 78 cultural resources (i.e., 64 archaeological sites and 14 isolated finds). Included in that inventory was site 41GU177, originally discovered on August 31, 2015 on the west bank of the Guadalupe River. Site 41GU177 is a stratified prehistoric site on the western high bank of the Guadalupe River southeast of New Braunfels, Texas near the community of McQueeney. The site contains components deposited intermittently from approximately the Late Archaic to Transitional Archaic periods through Late Prehistoric times. The primary components investigated in the excavations span the final Late Archaic period and into the Austin phase of the Late Prehistoric, a timeframe from approximately 2,600 to 900 years ago. The field investigations, conducted between October 2016 and December 2017, included intensive shovel testing, geomorphological study with mechanical excavations, and subsequent hand excavations. This report presents the results of the data recovery investigations conducted from November–December 2017. The survey results and testing results have been previously reported on (Acuña et al. 2016; Rodriguez et al. 2017); the testing results are also presented in Appendix A. SWCA’s work at 41GU177 was conducted under the ACT. The state regulations mandate the evaluation of the site’s eligibility for designation as a State Antiquities Landmark (SAL) or for listing on the National Register of Historic Places (NRHP). The survey and testing investigations were conducted under ACT Permit No. 7295, and the subsequent data recovery was completed under Permit No. 8231. Brandon S.Young served as initial Principal Investigator (PI) on both permits and Christina Nielsen took over asPI on the permits for the final reporting stages of the project. Overall, 34.1 m3 of sediment was excavated from the site during the data recovery through both traditional and feature-focused unit excavations. During these excavations, approximately 22 m2 of Late Prehistoric components were exposed, consisting of rock-lined hearths and 6,496 artifacts. The Late Prehistoric artifacts included Edwards points, Perdiz points, a Fresno point, ceramics, bifaces, an end scraper, a shell bead, various informal lithic tools, ground stone, choppers, debitage, and faunal remains. The Late Prehistoric component was approximately 40–80 cm thick. No cultural features were identified within the underlying Archaic components of the site; however, 3,421 artifacts were recovered including a Zephyr point, bifaces, ground stone, various informal lithic tools, choppers, debitage, and faunal remains. The Transitional Archaic component was approximately 35–60 cm thick; however, the underlying Archaic (and possible older) components were not defined. The excavations were limited to the right-of-way, and consequently the exposure afforded only a partial glimpse of the overall site. Based on the assemblage, the site is interpreted as a logistical base camp as indicated by both formal and informal tool forms and site furniture. Small groups exploited the abundance of lithic raw material and riparian zone resources, making forays into the landscape to hunt and forage. A total of four radiocarbon dates from the Late Prehistoric components reveal several short-term encampments over the course of several centuries from approximately 600 to 1200 B.P. (A.D. 750 to 1350). The Toyah Phase component has some noted disturbances (especially towards the ground surface), but good integrity from where the radiocarbon sample was collected. The Austin Phase component is vertically and horizontally discrete, contains a substantial amount of archaeological materials, and the site structure and radiocarbon dates suggests multiple, discrete occupations. The data recovery investigations at the Snakeskin Bluff site sought to address environmental, technological, chronological, and adaptive changes during the transition from Archaic to Late Prehistoric. As mentioned, the overall artifact and feature recovery at the site was low and disturbances and mixing of components was noted, especially within the upper deposits of the site. Disturbances within the Late Prehistoric Toyah Phase were most prevalent in the eastern portions of the site. The Late Prehistoric Austin Phase component contained intact, well-preserved archaeological deposits containing preserved flora and faunal material, cooking features, and diagnostic implements. The Transitional Archaic (and older) occupations were difficult to characterize, due to limited quantities of temporal diagnostic artifacts, lack of cultural features, and low artifact recovery. Despite these limitations, the data recovered from the cultural components show diachronic shifts between the technological and foraging strategies of the Archaic and Late Prehistoric. In concurrence with the 2016–2017 testing recommendations, the Snakeskin Bluff site is considered eligible for designation as an SAL and for the NRHP. Although not all cultural components of the site were stratigraphically discrete, the Late Prehistoric Austin Phase component revealed intact, well-preserved archaeological deposits that significantly contributed to our understanding of Late Prehistoric patterns. Given the sensitive nature of the cultural deposits at 41GU177, the main concern following the completion of data recovery excavations was the prevention of significant surface and subsurface impacts to the site during clearing and pipeline construction. As such, SWCA developed a site monitoring protocol; methods and results of the monitoring efforts are provided in Appendix H. Contributing components beyond the impact area will not be affected and will be preserved by avoidance; however, it is important to note that these investigations mitigated the project-specific effects, not the entire site. Any future project that could impact the site’s deeper deposits, or those beyond the current right-of-way, warrant further consideration to assess the possibilities for additional contributing components. With these considerations, no further work is recommended.