O’Neill, Brian L. , Thomas J. Connolly, and Dorothy E. Freidel, with contributions by Patricia F. McDowell and Guy L. Prouty. A Holocene Geoarchaeological Record for the Upper Willamette Valley, Oregon: The Long Tom and Chalker Sites. University of Oregon Anthropological Papers 61, Published by the Museum of Natural History and the Department of Anthropology, University of Oregon, Eugene. 2004.

Data recovery investigations at two prehistoric sites were prompted by the Oregon Department of Transportation’s realignment of the Noti-Veneta segment of the Florence to Eugene Highway (OR 126) in Lane County, Oregon. The Long Tom (35LA439) and Chalker (35LA420) archaeological sites are located on the floodplain of the Long Tom River in the upper Willamette Valley of western Oregon. Investigations at these sites included an examination of the geomorphic setting of the project to understand the processes that have shaped the landscape and to which its human occupants adapted. The cultural components investigated ranged in age between about 10,000 and 500 years ago.

Geomorphic investigation of this portion of the Long Tom River valley documents a landform history spanning the last 11,000 years. This history is punctuated by periods of erosion and deposition, processes that relate to both the preservation and absence of archaeological evidence from particular periods. The identification of five stratigraphic units, defined from trenching and soil coring in the project area, help correlate the cultural resources found at sites located in the project. Stratigraphic Unit V, found at depths to approximately 250 cm, is a clayey paleosol with cultural radiocarbon ages between 11,000 and 10,500 cal BP. Unit N, with radiocarbon ages between approximately 10,000 and 8500 cal BP, consists of fine-textured sediments laid down during a period of accelerated deposition. An erosional unconformity separates Unit IV from the overlying Unit III. In the archaeological record, this unconformity represents a gap of nearly 3000 years, from 8500 to 5700 cal BP, and corresponds to a period of downcutting in the Willamette system that culminated with a transition from the Winkle to Ingram floodplain surfaces. Unit III sediments are sandy loams within which are found numerous oven features at the Long Tom, Chalker, and other nearby archaeological sites, and date between approximately 5700 to 4100 years ago. A near absence of radiocarbon-dated sediments in the project area between approximately 4100 and 1300 years ago suggests either a lack of use of this area during this period, or an erosional period that was apparently less severe on a regional scale. Units II and I are discontinuous bodies of vertically accreted sediments which represent a period of rapid deposition in the project area during the last 1300 years. It is estimated that Unit I sediments were deposited within the last 500 years.

Investigations at the Long Tom site discovered three cultural components. Components 1 and 3 are ephemeral traces of human presence at the site. The Late Holocene-age Component 1, found within Stratigraphic Units I and II, contains a small assemblage of chipped stone tools and debitage dominated by locally obtainable obsidian. The Early Holocene-age Component 3 contains a single obsidian uniface collected from among a scatter of fire-cracked rock and charcoal found within Stratigraphic Unit IV. Charcoal from this feature returned a radiocarbon age of 9905 cal BP. Contained within Stratigraphic Unit III, Component 2 presents evidence for a concentrated period of site use between approximately 5000 and 4000 cal BP. Geophysical exploration of the deep alluvial sediments with a proton magnetometer located magnetic anomalies, a sample of which was mechanically bisected and hand-excavated for closer analysis. A total of 21 earth ovens and two rock clusters was exposed in sediments associated with radiocarbon ages clustering about 4400 cal BP. Charred fragments of camas bulbs and hazelnut and acorn husks were recovered from the ovens. Few tools were discovered in their vicinity. Larger-scale excavations within the Middle Holocene sediments at the west end of the site discovered what is interpreted as a residential locus.

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