Cooper Bison Kill Site

Cooper Bison Kill Site
Name	Cooper Bison Kill Site
Map type	United States
Location	Near Glenrock, Converse County, Wyoming
Region	North America
Type	Kill site
Built	ca. 10,200–10,300 BP
Epochs	Late Pleistocene–Early Holocene
Cultures	Clovis, Folsom (debated)
Excavations	1960s–2000s
Archaeologists	Glenn H. Irwin, William A. Ritchie, Larry Agenbroad
Ownership	Private and public land

Cooper Bison Kill Site The Cooper Bison Kill Site is an Early Holocene / Late Pleistocene archaeological locality in Converse County, Wyoming, notable for its mass bison procurement evidence and stratified artifact-bearing deposits. Discovered during regional surveys for University of Wyoming and Wyoming State Archaeologist programs, the site has informed debates about terminal Pleistocene subsistence, migration, and lithic technology across the Great Plains, Rocky Mountains, and Central Plains.

Location and discovery

Located near Glenrock in eastern Wyoming, the site sits within the paleoenvironmental corridor linking the North Platte River drainage and the Powder River Basin, positioned on loess and alluvial terraces that preserve kill and processing loci. Initial identification derived from surface finds by local landowners and surveys associated with the National Park Service inventory and regional work by researchers from the University of Wyoming and the Wyoming Geological Survey. Subsequent reconnaissance involved coordination with agencies such as the Bureau of Land Management and the Smithsonian Institution for collections and comparative analysis.

Archaeology and excavation

Systematic excavation campaigns at the site were led by regional archaeological teams in sequential seasons, employing stratigraphic trenching, grid-controlled excavation, and screening methods developed in the 20th century by practitioners trained in institutions like Harvard University, University of California, Berkeley, and University of Arizona. Fieldwork incorporated sedimentology from the United States Geological Survey protocols, taphonomic assessment methods advanced by scholars connected to the American Antiquity research community, and faunal analysis techniques refined in labs at the Smithsonian Institution National Museum of Natural History. Excavations recovered concentrations of projectile points, flake debris, and skeletal elements, with field records curated under accession policies similar to those at the Peabody Museum of Archaeology and Ethnology and the American Museum of Natural History.

Faunal remains and stratigraphy

The assemblage is dominated by multiple individual bison skeletons, identified as members of the genus Bison and compared with reference collections from the Smithsonian Institution and the Natural History Museum, London for species and ontogenetic determination. Skeletal distributions indicate repeated mass harvest events and in situ butchery, with bone bed stratigraphy showing discrete occupation lenses separated by loess and flood-deposited silt correlated to regional paleosols studied by the United States Department of Agriculture and USGS researchers. Bone surface modifications interpreted through comparative frameworks from the Society for American Archaeology literature include cut marks, percussion scars, and carnivore gnawing consistent with human processing and post-depositional agencies documented at other North American kill sites.

Dating and paleoenvironment

Chronometric control relies on radiocarbon dates generated at facilities such as the Arizona Accelerator Mass Spectrometry Laboratory and the University of Waikato Radiocarbon Dating Laboratory, situating events around the terminal Pleistocene to early Holocene transition, roughly 10,200–10,300 radiocarbon years before present. Paleoenvironmental reconstructions draw on palynology, phytolith studies, and stable isotope results comparable to records from the Greenland ice core chronologies and regional paleoclimatic syntheses performed by investigators affiliated with the National Oceanic and Atmospheric Administration and the Paleoclimate Research Unit. These data imply a mosaic of grassland and parkland habitats influenced by post-glacial warming, affecting bison herd behavior and human subsistence strategies contemporaneous with groups documented in the Plains Archaic sequence and late Paleo-Indian contexts.

Cultural affiliation and tool assemblage

The lithic inventory includes fluted and non-fluted projectile points, bifaces, and percussion flakes made from local and non-local cherts and cryptocrystalline silicates sourced from outcrops comparable to those at the Hartville Uplift, Wind River Range, and the Roche Jaune (Yellowstone region) procurement zones. Typological comparisons link elements of the assemblage to well-known cultural complexes documented by researchers studying Clovis culture, Folsom culture, and later Plano cultures, although debate persists regarding direct affiliation. Technological analyses employ methods from lithic studies associated with the Smithsonian Institution and the University of Colorado, integrating microwear and refitting studies to infer hafting, projectile delivery systems, and on-site reduction strategies.

Significance and interpretations

The site contributes to broader discussions about Late Pleistocene human ecology, mobility, and social organization across North America, informing models developed by scholars at institutions such as the University of Kansas, Texas A&M University, and the University of Texas at Austin. Interpretations emphasize cooperative hunting, landscape use, and resource intensification during climatic amelioration following the Younger Dryas event, intersecting with debates over megafaunal responses to human predation as articulated in research affiliated with the National Science Foundation and international paleoecological syntheses. As a well-preserved kill and processing locus, the site remains a reference point in comparative studies involving other major localities like Mammoth Site of Hot Springs, South Dakota, Blackwater Draw, and Lehner Ranch, shaping our understanding of terminal Pleistocene lifeways on the North American Plains.

Category:Archaeological sites in Wyoming Category:Paleo-Indian archaeological sites