B. Robert Butler conducted the first controlled excavations at the Cooper’s Ferry site in the summers of 1961 and 1962 and later in 1964. The recovery of a sequence of stemmed and willow leaf-shaped projectile points in a stratified sequence from four adjacent 2 meter by 2 meter excavation units, which form Butler’s Trench A, were presented in a report of investigations (Butler 1969). Although this evidence is commonly cited as an example of early Plateau cultural manifestation (e.g., Bryan 1980; Carlson 1983; Ames 1988), chronometric control could not be established for the deeply buried cultural components that yielded what Butler termed “Lind Coulee-like” stemmed points after the southeastern Washington area site of the same name.
In his doctoral dissertation, D.G. Rice (1972) hypothesized that an evolutionary relationship might exist between the Columbia River Plateau’s early Lind Coulee technological tradition (Daugherty 1956) and the Windust cultural type (Leonhardy and Rice 1970). The pursuit of this hypothesis was possibly the impetus for his decision to conduct limited excavations at the Cooper’s Ferry site in 1976. Although the results of this investigation were never published, some fieldnotes and a collection of artifacts are available in the University of Idaho archaeological repository. These materials were reviewed by the author in the winter of 1997. Information gleaned from these collections is discussed here in order to present a broader perspective on site geology and archaeological content.
The first stratigraphic profiles to be described at Cooper’s Ferry were presented by Butler (1962, 1969). Butler (1969) describes a series of sandy deposits with varying proportions of silt and some inclusive rocks, all of which were underlain by well rounded carbonate-coated cobble gravels with an irregular upper boundary. Butler provides interpretations on the genetic origin of the sediments, classifying the fine sediments as wind blown in nature with the inclusion of occasional gravity deposited clasts from the nearby canyon slope. Varying proportions of calcium carbonate are seen in the sediments, with the highest percentages seen in the lower deposits. The underlying rounded gravels are classified as riverine, which were eroded during a deglacial adjustment of the Salmon River, estimated as occurring at ca. 12,000 BP (Butler 1969:38).
In 1996, a cooperative archaeological research project was developed between the University of Alberta and the Bureau of Land Management (BLM) to evaluate several aspects of LSRC prehistory and Quaternary geology. Within the scope of this research, a single 2 m by 2 m test unit (named Unit A) was placed at the Cooper’s Ferry site in the summer of 1997 in order to attain several research goals, including: (1) confirm the stratigraphy recorded during earlier investigations and to place it in a larger framework of lower Salmon River canyon late Quaternary geology; (2) collect samples for radiometric dating and; (3) gather a wider array of data for more comprehensive archaeological and geoarchaeological analyses of early human life in the canyon.
Prior to excavating at the Cooper’s Ferry site during the 1997 season, several aspects had to be considered since the surface of the bench containing the site experienced much disturbance over the last century. According to local accounts, parts of the Cooper’s Ferry site were used as a wagon road and a ferry launch by early Euroamerican settlers of the canyon and adjacent Joseph and Doumecq Plains. Later, the Salmon River road was widened, approximating its modern form. Canyon residents recalled various occasions where excess fill material had been placed on the surface of the site. Butler (1969:36) noted disturbed sediments in the upper portions of some areas of the bench, which caused him to abandon excavation in certain test units and to remove turbated fill with a backhoe in others. In 1976, D.G. Rice placed a 3 m by 2 m test unit to the east of Butler’s Trench A. In 1983, the Bureau of Land Management placed a large quantity of rock fill on exposed cutbanks at the southern edge of the site (see Butler (1969:46) for position of cutbanks), in order to reduce erosion and to protect the site from vandalism (David Sisson, written communication 2001). Based on these considerations, we placed Unit A in the northwestern portion of the bench, in the area of an older road shown in Butler’s site map (1969:46), in hopes of avoiding any site disturbance. While the excavation of a test unit in the area of a old road may seem counterproductive to our goals, it was reasoned that while some shallow disturbance might exist in the area, road surfaces are typically excluded from certain site disturbing activities, such as sand quarrying and the digging of garbage pits. Our reasoning was rewarded by the discovery of a long, almost entirely undisturbed stratigraphic record. Geoarchaeological and archaeological aspects of the 1997 test excavations are reported by Davis and Schweger (2004). Notably, the 1997 excavations discovered a circular pit in the site’s lower deposits, which contained stemmed projectile points and other stone tools. Davis and Schweger (2004) argue that the early occupation of the site probably dates to the late Pleistocene period, and could be as early as 13,270 calendar years ago.
In 2009, Loren Davis resumed excavations at Cooper’s Ferry as part of a multiyear effort to address several outstanding questions related to site chronology, cultural adaptation and change through time, and the paleoenvironmental context of precontact peoples of the lower Salmon River canyon. The 2009 excavations accomplished several things. First, Davis’s team relocated and uncovered the 1997 2 x 2 m excavation unit (Unit A) previously placed at the site. With Unit A open again, Davis
reestablished the site’s survey reference baseline, which runs north‐south through the western edge of Unit A to a survey cap placed by the BLM in 1997 at the northern end of the site. At 4 x 10 m block of 2 x 2 excavation units was built from this baseline. These new 2 x 2 m units (designated as Units B through J) formed the primary basis for our 2009 excavations. We also used a total station laser transit to establish daily provenience control in reference to the site baseline. Davis’s team also sought to control for the post‐depositional effects that burrowing rodents might have on the archaeological record of the Cooper’s Ferry site. To this end, they worked to identify, isolate, excavate, screen, and collect materials associated with rodent burrows (krotovina) as they were encountered during excavations. Davis’s team mapped 179 krotovina features in 2009 using the total station, which will ultimately be projected in three dimensional space to enable the study of rodents as a process of archaeological site formation. The 2009 excavations succeeded in removing most of the uppermost deposits of historic fill and riverine (i.e., alluvial) sands encountered in 1997. In the process of removing the alluvial sands, a shallow, ovate depression was found extending into the surface of lower brown alluvial deposits beneath the gray sands. Although the function of this depression feature is unclear at this time, it was infilled with lighter‐colored gray alluvial sands, which more easily enabled us to observe and carefully uncover the feature. An antler wedge and a flaked and polished stone wedge were found in direct association with each other, ca. 2 cm above the floor of the ovate depression feature in the overlying gray sands. The discovery of these unusual tools is hoped to reflect the quality of archaeological material assemblages to be encountered in deeper deposits during the 2010 excavations and thereafter.
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Bryan, A.L. 1980. The Stemmed Point Tradition: An Early Technological Tradition in Western North America. In, L. Harten, C. Warren and D. Tuohy (Eds.), pp. 77-107, Anthropological Papers in Memory of Earl H. Swanson, Jr. Special Publication of the Idaho State University Museum of Natural History, Pocatello.
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