Mapping of subsurface shell midden components through percussion coring: examples from the Dundas Islands

Following earlier examples of mapping the subsurface of shell bearing sites using augering, we employ percussion coring to identify early Holocene shell midden components at two types of sites on the Northwest Coast of North America. We describe a method for mapping subsurface components at shell bearing sites including basal deposits, paleosols and transitions between distinct cultural components. Our research was undertaken for the purpose of identifying early Holocene shell middens above the modern shore, and as components below large shell midden villages. Our results augment the developmental trajectory of shell middens on the Northwest Coast by suggesting that pre-5000 BP forms of these sites may be more common than previously thought. In light of these results, we argue that the Northwest Coast cultural historical sequence, which locates an increase in the number and rate of accumulation of shell middens beginning 5000 years ago, to be premature. However, there are insufficient data from shell middens in the early Holocene, a sampling problem that the percussion coring methods described here can address.