Obsidian in the Salish Sea: An archaeological examination of ancestral Coast Salish social networks in SW British Columbia and NW Washington state

Abstract Obsidian toolstone from local and nonlocal sources played an important role in the daily lives of ancestral Coast Salish populations in the Salish Sea region of southwestern British Columbia and northwestern Washington state. We suggest that the presence of nonlocal obsidian is explained by down-the-line trade along social networks that extended access beyond the local. We also contend that these networks enabled the expression of territorial and tenurial claims as part of ongoing practices associated with gaining, maintaining, and legitimizing access to distant resources. Although obsidian from a variety of toolstone sources located in Oregon and Washington states, and north of the Salish Sea, was widely available to ancestral Coast Salish over much of the last six millennia, distribution was uneven. Furthermore, there is some indication that the lower Fraser Valley was an important corridor for much of the Oregon toolstone to reach other Central and Northern Coast Salish communities. We combine ethnography and archaeology to investigate the relationship between ancestral Coast Salish social networks and the distribution of obsidian toolstone in the Salish Sea region.