The Long Tom and Chalker Sites
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.
Abstract:
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.
Archaeological investigations at the Chalker site identified three cultural components. Component 3, the oldest of the three, contains a small portable tool assemblage and is represented by a well-preserved earth oven with an associated radiocarbon age of 4610 cal BP, roughly contemporaneous with the Middle Holocene-age Long Tom site occupation. Component 3 is found within Stratigraphic Unit III sediments. The upper two components are of Late Holocene-age, with projectile point assemblages dominated by small (arrow-size) specimens. Component 2, perhaps the most intensively occupied period, dates between 1280 cal BP and 925 cal BP, and lies within Stratigraphic Unit II sediments. In addition to narrow-necked and small stemless projectile point types. the artifact assemblage includes drills, other bifaces, unifaces, utilized flakes, chopper/cores, hammerstones, a hammer/anvil stone, and split and unsplit obsidian pebbles. Excavations may have exposed a temporary warm-weather shelter. The artifact assemblage of Component 1, found within Stratigraphic Unit I sediments, is dominated by projectile points associated with radiocarbon ages ranging between 660 cal BP and 510 cal BP.
The proton magnetometry undertaken at the Chalker and Long Tom sites was the first use of this remote sensing technique in western Oregon. The fine-grained silt of the Long Tom River valley, within which the cultural deposits were buried, provided an unusually good environment for the use of this prospecting method. Maps produced from the survey results guided excavations and provided information regarding the number of extant earth ovens and their location.
Macrobotanical analysis of samples recovered from the Chalker and Long Tom sites identified eight economically important plant species including hazel, acorn, camas, thimbleberry, chokecherry, Indian plum, Miner’s lettuce, and bedstraw. Most significantly, camas was found in Middle Holocene-age oven features, calling into question the hypothesis that this time period had been too xeric for exploitation of this root crop.
Obsidian studies of debitage from the Chalker and Long Tom sites found that the vast majority of the material found at these sites during all periods of occupation was locally obtained Inman Creek-A and Inman CreekB obsidian. The Middle Holocene-age assemblages of both sites, however, contain small proportions of exotic obsidian from the more distant Obsidian Cliffs and Newberry Volcano sources. Hydration analysis of lnman Creek types A and B yield no noticeable difference in their rates of hydration.
Evidence obtained from data recovery of the Middle Holocene-age components of the Chalker and Long Tom sites, coupled with information collected from other sites in the region, present a pattern of intensification in the exploitation of camas during a 1000 year period beginning approximately 5000 years ago.
The culture history of the Willamette Valley is inextricably tied to a landform which also has a dynamic history. This report, coupling the findings of geomorphology and archaeology, is a pioneering effort in its attempt to understand the relationship of the human use of the changing landscape in the upper Willamette Valley during the last 11,000 years.
