Introduction
Dalles 21-71 is a designated archaeological site located in the vicinity of The Dalles, Oregon, along the lower Columbia River corridor. The numeric designation follows the Oregon State Archaeological Survey’s standard site numbering system, wherein “21” represents the county (Linn County) and “71” indicates the sequential identification of the site within that county. The site lies adjacent to the historic riverbank at an elevation of approximately 200 feet above sea level, and it occupies a floodplain area that has been subject to periodic inundation over the past millennia. Because of its strategic position along the Columbia River and its association with precontact indigenous cultures, Dalles 21-71 has attracted considerable scholarly attention, serving as a focal point for investigations into settlement patterns, subsistence strategies, and interregional exchange networks in the Pacific Northwest.
Location and Geology
Topographic Setting
The Dalles 21-71 site is situated within a lowland alluvial plain that drains into the Columbia River. The surrounding topography is characterized by gently sloping terraces composed of glacial outwash and Holocene loess deposits. The site’s proximity to the river has historically facilitated trade, transportation, and resource procurement for riverine communities.
Soil and Sediment Stratigraphy
Core samples extracted from the site reveal a sequence of sedimentary layers that reflect both natural deposition processes and anthropogenic activity. The uppermost layer is a loamy surface soil rich in organic matter, indicating a relatively recent occupation phase. Beneath this lies a sublayer of paleosols, which are indicative of ancient surface soils that experienced periods of stabilization before subsequent flooding. Further down, a series of silty deposits correspond to historic flood events that delivered fine-grained material from upstream sources.
Paleoenvironmental Reconstruction
Palynological analyses of sediment cores from the Dalles 21-71 vicinity indicate a gradual transition from boreal coniferous forests to mixed conifer-hardwood assemblages over the last 4,000 years. This shift is correlated with climatic fluctuations that influenced plant community composition and, by extension, the availability of plant-based resources for human populations. Additionally, charcoal fragments found in the middle strata of the site suggest episodic fire use, which may have been intentional for landscape management or a natural consequence of climatic conditions.
Historical Context
Prehistoric Occupation
Archaeological evidence suggests that the site was first occupied during the Late Archaic period (c. 3,500–2,000 BCE). Excavations uncovered a series of lithic scatters and hearth features that are characteristic of mobile hunter-gatherer groups engaged in riverine foraging. Stone tools recovered from the earliest layers include flake knives, projectile points, and scrapers made from local chert and basalt sources.
Protohistoric Era and Contact
During the Protohistoric period (c. 150–185 CE), the Dalles region became increasingly integrated into trade networks that connected the Columbia River basin with interior plateau communities. Artifacts from this era include obsidian blades from the Wasatch Mountains, as well as imported shell beads that indicate long-distance exchange. The site also contains early evidence of the adoption of pottery technology, which coincides with broader cultural transitions in the region.
Historic Period and Modern Developments
Following European contact, the area surrounding Dalles 21-71 underwent significant transformation. The construction of the Lower Columbia River Bridge in the late 19th century, the subsequent development of the Dalles Dam in the mid-20th century, and the implementation of flood control measures altered both the hydrology and the archaeological visibility of the site. These modern developments have presented both challenges and opportunities for archaeologists seeking to understand the site's long-term occupation history.
Archaeological Investigation
Survey and Site Identification
The site was first recorded during a statewide archaeological survey conducted by the Oregon Department of Archaeology and Historic Preservation in the 1970s. Fieldwalking and geophysical techniques such as ground-penetrating radar were employed to delineate the extent of occupation layers and to identify subsurface features. The survey confirmed the presence of a distinct habitation area bounded by a natural levee on the north and a shallow channel on the south.
Excavation Strategy
Excavations at Dalles 21-71 have followed a stratigraphic approach, with trenches positioned to capture a cross-section of the site's vertical profile. Standard archaeological protocols were adhered to, including the use of sieving, flotation, and detailed recording of spatial coordinates for all finds. Stratigraphic units were assigned numerical designations to facilitate chronological sequencing and to allow for comparative analyses with other regional sites.
Laboratory Analysis
Recovered artifacts and ecofacts were subjected to a range of laboratory analyses. Radiocarbon dating of charcoal samples provided absolute dates for occupation layers, while lithic typology offered insights into technological practices. Phytolith and pollen analyses contributed to reconstructing past vegetation and subsistence strategies. Additionally, use-wear studies on stone tools helped elucidate the tasks performed by site occupants.
Key Findings
Subsistence Strategies
Faunal remains from the Dalles 21-71 site reveal a diet that incorporated both aquatic and terrestrial resources. Fish species such as salmon, steelhead, and sturgeon dominate the faunal assemblage, underscoring the importance of riverine fisheries. Small game, including deer and elk, also appear in significant quantities, indicating seasonal hunting activities. Plant remains, identified through flotation, include nuts, tubers, and wild grains, suggesting a diversified foraging strategy.
Technological Practices
The lithic assemblage demonstrates a high degree of technological sophistication. Point types include stemmed and corner-notched forms characteristic of the Late Archaic period, as well as later projectile points with distinctive flaking patterns indicative of Protohistoric influences. The presence of obsidian tools points to long-distance procurement networks, as the nearest sources of obsidian lie several hundred kilometers upstream.
Ceramic Evidence
Pottery sherds recovered from the Protohistoric layers are associated with the Pacific Northwest ceramic tradition. Features such as cordmarking, rim lugs, and specific slip decorations provide clues to cultural affiliation and technological diffusion. The tempering material, primarily sand, suggests a technique employed by local groups rather than imported vessels.
Social and Economic Organization
Spatial distribution of features within the site, including hearths, post molds, and storage pits, points to a complex settlement organization. The arrangement of activity areas suggests that Dalles 21-71 functioned as a seasonal camp with a specialized layout that facilitated division of labor and efficient resource processing. The evidence of trade goods implies that the site was a node within broader exchange systems, potentially serving as a gathering place for intertribal interaction.
Cultural Significance
Regional Contextualization
When viewed in the context of the Columbia River basin, Dalles 21-71 exemplifies the adaptive strategies employed by riverine societies. Its occupation layers align temporally with the emergence of large-scale trade networks, while the material culture reflects a blend of local production and external influences. Comparative studies with neighboring sites such as Hohokam Creek and Morrow Point enhance understanding of regional variation in subsistence and technology.
Ethnohistorical Perspectives
Ethnographic records from the Wasco-Wishram and Walla Walla tribes provide complementary information regarding traditional fishing practices, seasonal migration patterns, and spiritual significance of the Columbia River. Oral histories emphasize the importance of salmon runs and highlight the cultural memory associated with riverine sites. The integration of archaeological data with these ethnographic sources offers a holistic view of the human-environment relationship in the region.
Conservation and Management
The Dalles 21-71 site has been designated as a protected area under state and federal regulations. Management strategies emphasize minimal disturbance of the site, with periodic monitoring to assess potential impacts from flooding and anthropogenic activities. Collaboration with tribal partners ensures that cultural values are respected and that heritage preservation aligns with community priorities.
Conservation and Management
Legal Framework
Under the National Historic Preservation Act and the Oregon Antiquities Act, Dalles 21-71 is recognized as a site of archaeological significance. These statutes provide mechanisms for safeguarding the site's integrity, including the requirement for impact assessments prior to any development in the vicinity.
Site Preservation Practices
Preservation efforts involve the stabilization of exposed stratigraphic sections, controlled excavations, and the installation of protective fencing where necessary. Soil conservation measures, such as erosion control and vegetation management, are employed to mitigate the effects of natural and human-induced degradation.
Research Collaboration
The site serves as a focal point for collaborative research among universities, state agencies, and indigenous communities. Joint projects focus on advancing scientific methodologies, such as high-resolution radiocarbon dating and GIS-based spatial analysis, while also fostering cultural education programs.
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