By Amy Reid
Lab tables cluttered with artifacts, scales, digital calipers, coffee cups, Excel spreadsheets and to-do lists that seem to get longer-not shorter. The analysis phase of an archaeological project can look more like chaos than science, but in reality there is a method — or methodology rather — to the madness. This post aims to describe the various analyses we have conducted and are planning to perform on the data recovered from our 2014 excavations at the Spring Lake Site. You will also get a sneak peak at some of the results available to date.
Like most systematic archaeological projects, my colleagues and I identified a series of research questions and objectives before the excavations even began. All of our work planning, excavating, sampling and processing (washing, sorting and cataloging) the artifacts was performed with 3 research domains in mind:
- chronology and culture historical reconstruction;
- geoarchaeology, site formation, and environmental reconstructions; and
- better defining the Calf Creek horizon at Spring Lake, including its technological characteristics and how subsistence-related behaviors changed during this brief interval of big game (bison) hunting at the end of the Early Archaic, ca. 5750 to 6000 years ago.
The analyses planned to address these questions cannot begin until there is 1) a complete catalog of artifacts, ecofacts and samples collected, and 2) a preliminary list of Analytical Units (AUs). AUs are a set of discrete, intact deposits of sediment that represent recognizable periods in the occupational history of the site. They are chronological in nature, and therefore rely on the law of superposition, cross-dating principles, typology, and context. Ultimately, the AUs will be a series of excavated proveniences that can be associated with a given time period that will provide the basis for all detailed, context-specific analyses that will be conducted. This step is vital for assessing behavioral changes through time. I refer to them here as preliminary because eventually the AUs will be updated and refined once we have absolute dates from bone and charcoal.
The first step in the process of defining AUs, was to take a closer look at the time-diagnostic projectile points. I went through the entire collection of points and point fragments and conservatively assigned types to the specimens that fit within existing type definitions. The typological outliers and the specimens that I could not identify with confidence (or as I have typed them, “Elton Points”) were set aside to be examined by Elton Prewitt, an independent researcher and expert in Texas projectile point typology (Figures 4 and 5). Elton has graciously assisted us with typing projectile points from previous projects in and around the Spring Lake site and his help is much appreciated for the sake of consistency within our ongoing studies at this important site.
In all, twenty six different temporally diagnostic projectile point types were found during our 2014 excavations at Spring Lake, including: Wilson and Dalton of the Paleoindian (n=5); Gower, Uvalde, Bandy, Merrell, and Martindale of the Early Archaic (n= 13); Bell (Calf Creek) from the Calf Creek component (n=6); Baird (aka Taylor or Early Triangular), Nolan, Travis, Desmuke and Pandale from the Middle Archaic (n=25); Bulverde, Castroville, Ellis, Edgewood, Ensor, Fairland, Marcos, Montell, Morhiss, Pedernales, Lange, Marshall and Darl of the Late Archaic (n=59); Scallorn and Perdiz arrow points of the Late Prehistoric (n=7) (Figures 6-10).
My next step involved discussions with Jacob Hooge our resident Geoarchaeologist about which excavation units showed signs of post depositional disturbances. In other words, he gave me a list of excavated units and levels that were considered to have mixed deposits that I should therefore avoid when defining the AUs. Then, the typed projectile points that were recovered from within unit levels that were determined to have good contextual integrity were evaluated stratigraphically. Unit-levels that showed evidence for more than one time period were considered mixed or compressed and were not considered reliable for analysis. Alternately, unit-levels that did not contain any time-diagnostic information at all did not receive an analytical unit designation since it would be impossible to know whether these contain mixed or intact deposits.
Currently, the analytical units for our SLDR project include a series of lots (proveniences) that correspond with all of the general Prehistoric time periods in the existing Central Texas chronology from the Toyah phase of the Late Prehistoric at the top to the Late Paleoindian at the bottom (Figures 11 and12).
Importantly, we encountered intact Calf Creek components in both excavation blocks at similar elevations. These, alongside the Calf Creek component recorded during our 2012 data recovery excavations at Spring Lake (Lohse et al 2012) are believed to be the only intact Calf Creek components with datable materials yet documented in Central Texas!
Chronometric dating of Carbon (C14) and bone will help refine these AUs making it possible to observe a more precise scale of resolution that corresponds to intervals or phases defined for Central Texas by Prewitt 1981, 1983, 2005), Johnson and Goode (1994) and Lohse (2012) (see table). In particular, we hope to advance our understanding of the Calf Creek interval at Spring Lake. The Calf Creek horizon currently believed to have occurred during the terminus of the Early Archaic at Spring Lake. We have sent off 14 samples of carbon from the above described AUs to undergo AMS Radiocarbon dating and are patiently awaiting the results.
The faunal bone from our preliminary AUs will be identified by a faunal analyst (TBD) and then studies on subsistence at Spring Lake will be possible. Following identification, we plan to submit a selection of bison bone to be dated which will allow us to reconstruct periods of intensive focus on bison exploitation.
Another special study we are excited about is protein residue. A selection of lithic tools from our 2014 excavations at Spring Lake have been submitted for protein residue analysis, which will identify presence of animal and/or plant proteins on the tools.
We have also focused our attention on a feature that appears to be an intact cooking feature – Feature 6 (Figures 13 and 14). Feature 6 consists of a high concentration of burned rock below and surrounding an area full of burned clay. Interestingly, a dart point was found from within the feature with a potlid still in place. This point has been preliminarily typed as an Ensor, suggesting the feature may have been used during the Late Archaic time period. However, multiple lines of evidence will ultimately be used to date Feature 6 including both AMS radiocarbon dating and thermoluminescence dating. Archeobotanical analyses are also planned for this feature by way of flotation. Thanks to the help of Leslie Bush, we have already begun the flotation process for sediment samples from our AUs (Figure 15).
Check back for more posts on the results of these analyses as well as special studies on ceramics, bone and shell beads, and the possibility of prehistoric dwellings at Spring Lake.
Johnson, LeRoy, Jr., and Glenn T. Goode
1994 A New Try at Dating and Characterizing Holocene Climates, as well as Archeological Periods, on the Eastern Edwards Plateau. Bulletin of the Texas Archeological Society 65:1–51.
Lohse, Jon C., Amy E. Reid, David M. Yelacic, and Cinda L. Timperley
2013 Data Recovery and Analysis at the Texas State University Ticket Kiosk Project, Located at 41HY160, Spring Lake, Hays County, Texas. Center for Archaeological Studies: San Marcos
1974 Preliminary Archeological Investigations in the Rio Grande Delta Area of Texas. Bulletin of the Texas Archeological Society 45:55–65.
1981 Culture Chronology in Central Texas. Bulletin of the Texas Archeological Society 52:65–89.
1985 From Circleville to Toyah: Comments on Central Texas Chronology. Bulletin of the Texas Archeological Society 54:210-238.
Amy Reid is the Collections Manager at the Center for Archaeological Studies, and director of the PAST Program. She earned her Masters degree from Texas State University, and teaches a course in Archaeological Curation during the Fall semester.