The Vore Buffalo Jump is a sinkhole east of the site, hidden by the red eroded landscape, that served early residents as a slaughterhouse where hunters trapped bison in late fall by driving herds over the edge, then butchered the animals for winter food and supplies. Hunters camped downwind and out of sight, made ceremonial preparations, and days before the hunt scouts gathered 200-500 bison cows and calves a few miles from the kill site because a large herd was easier to control and provided more food than a small one. To begin the hunt, one hunter dressed in a bison hide to resemble a calf slowly decoyed the herd toward the sinkhole while other hunters followed and urged the animals forward without stampeding them until the very end; approaching from a curved natural drainage ditch, the bison did not see the pit before toppling into it, and those that survived the fall were killed by hunters waiting nearby. This was one of thousands of jump sites in the West, many dating back thousands of years, but it is significant because it was used relatively late, from 1500 to 1800, and shows evidence of contact between European and Plains Indian cultures. Arrow points from six or more different tribes during this short period document social upheaval partially caused by Euro-American expansion westward, and twenty-five feet of layered bison bones show changes in hunting and food processing, from using dogs to using horses to move carcasses. Introduced by Europeans, the horse revolutionized Plains Indian life and, once fully integrated into their cultures, replaced the need for the fall bison harvest because bison could then be hunted year-round. The site also stands out archaeologically for precise dating: annual rains and snowmelt washed eroded soil into the pit, burying bones and grasses in sediment layers called varves that can be counted like tree rings, reveal weather and ecological changes through thick wet-year and thin dry-year layers, and show that the jump was used every five to six years following wet years.