A reexamination of Livermore-Amador Valley prehistory through modified shell artifacts

The Livermore-Amador Valley in Alameda County, California comprises a host of prehistoric Native American archaeological sites within a relatively small area. The most recent archaeological excavation at site CA-ALA-554 in Pleasanton, California has revealed a considerable amount of data, especially in the burial associated artifacts. This thesis will focus on using modified shell artifacts as temporal indicators, and as a way to analyze multiple sites within a particular area to gain further knowledge of settlement patterns, chronology, and to discuss the significance or non-significance of shell artifacts in that regard. The main data of this paper have been gathered from site CA-ALA-554 and focus on the over 45,000 shell beads and the 453 shell ornaments excavated and recovered from over 130+ burials. The bead assemblage consists of Type B1, B2, M, and K that indicate a Late Period Phase I (based on dating Scheme B, developed by Bennyhoff and Hughes in 1987 and dating Scheme D, developed by Groza in 2002) occupation (see Table 1). This date is supported by the presence of Late Period Phase I diagnostic pendants. In addition, the presence of Type F, G, and C series beads suggests that a Middle through Middle-Late Transition (MLT) Period occupation existed, and albeit less intense than the Late Period occupation, was more significant than initially postulated from previous research conducted at CA-ALA-554 (Estes, et al. 2012, Estes et al. 2016). Possible reuse or preference for earlier bead type forms may have taken place as well. Analysis of modified shell artifacts illustrates patterns based on age, sex, position, location, and depth of the buried individuals. This paper will help contribute to a better understanding of bead and pendant chronologies and their regional variations within the Livermore- Amador Valley and the rest of California. The research questions for this paper focuses on whether the analysis of modified shell data collected and analyzed from site CA-ALA-554 provides significant conclusions to challenge current chronologies, trends, artifact typologies and burial practice patterns in Livermore-Amador Valley prehistory. The null hypothesis would be that based on the data gathered from modified shell artifacts of site CA-ALA-554, a level of nonsignificance exists whereas it would not be possible to re-organize aspects of current conclusions and trends regarding Bay Area prehistory. The research or alternative hypothesis is that the analysis of modified shell artifacts from CA-ALA-554 and cross correlation with other artifacts and aspects of surrounding sites, provides enough significance to draw new conclusions and amend previous theories concerning prehistory in the Livermore-Amador Valley as related to chronology.