The Wilbur Thomas Shelter Archaeological Site is a rockshelter in northwest Weld County featuring evidence of at least six intermittent occupations stretching over 8,500 years. David A. Breternitz and graduate students from the University of Colorado excavated the site in 1969. They found no evidence of long-term habitations and speculated that the site probably served as a shelter for hunting parties traveling between the mountains and the plains.
The Wilbur Thomas Shelter is about four miles southwest of Carr along the northern Front Range. It was named for landowner Wilbur Thomas. In 1968 Charles E. Nelson and Bruce Stewart investigated the site. They told David A. Breternitz of the University of Colorado about the shelter, and in spring 1969, he and his graduate seminar students in archaeology did excavations there. The students wrote reports about their work, which were published in Southwestern Lore in 1971. All excavation records and recovered artifacts were stored at the University of Colorado Museum of Natural History.
The Wilbur Thomas Shelter is notable for its deep deposits and long stratigraphic sequence. The excavation uncovered twenty hearths and fire pits at depths from eight inches to more than four feet. The team was not able to get radiocarbon dates for any of the material, but they found diagnostic artifacts (such as projectile points, knives, and ceramics), suggesting that the shelter had been occupied by six different cultural complexes, ranging from the Cody Complex in the Paleo-Indian period (before 6000 BCE) to Arapaho or Cheyenne groups in the Protohistoric period (1540–1860 CE).
Only two Cody Complex artifacts—a knife and a projectile point—were found, so it is possible that they represent reuse by a later group rather than a true Paleo-Indian period occupation. Later occupations—including the Mountain Complex in the Early Archaic period (5500–3000 BCE), the McKean Complex in the Middle Archaic period (3000–1000 BCE), the Plains Woodland in the Early Ceramic period (150–1150 CE), and perhaps the Upper Republican in the Middle Ceramic period (1150–1540 CE)—left more artifacts. Two copper rings and a cartridge casing in the site’s upper levels indicated continued use of the shelter after European contact.
The shelter contained no evidence of agriculture or long-term occupation, indicating that the people who stayed there were probably seasonal inhabitants who practiced hunting and gathering. The shelter’s Mountain Complex occupants probably used it as a base camp for their summer bison hunt before leaving in early fall to establish winter camp at a protected foothills site such as Magic Mountain or LoDaisKa. Later groups probably followed the same nomadic pattern of using the Wilbur Thomas Shelter during summer hunts on the plains and retreating to foothills sites for the winter. Hunting parties would have engaged in skinning, butchering, and tanning in and around the shelter. They also would have gathered nearby plants such as chokecherry and serviceberry to supplement the meat they acquired from hunting.