The Draper Cave Archaeological Site contains evidence of human occupation dating back to the Middle Archaic period (3000–1000 BCE). In 1972 the Denver chapter of the Colorado Archaeological Society excavated the site under the supervision of Ivol K. Hagar. The most important discovery was the skeleton of a young man who was interred with thirty-eight stone knives as a burial offering.
Draper Cave is in the Wet Mountain foothills a few miles west of Wetmore in the northeast corner of Custer County. It sits at the south end of a Dakota sandstone outcropping and faces east over the plains from an elevation of 6,580 feet. The cave is close to an intermittent stream and would have allowed easy access to both the mountains and the plains.
When Hagar and the Denver chapter of the Colorado Archaeological Society excavated the site in 1972, they found continuous cultural deposits for about four and a half feet below the ground surface. In addition to stone grinding tools such as metates and manos, the site contained McKean, Duncan, and Hanna projectile points, placing its dates of occupation in the Middle and Late Archaic periods (3000 BCE–150 CE). The team found no ceramic sherds, indicating that use of the site probably ended before the start of the Ceramic period in about 150 CE.
The site also contained three hearths and roughly 7,000 bone fragments, but the most significant feature was a burial found 2–3 feet below the surface. A radiocarbon date from the level of the burial placed it at about 1570 BCE, in the Middle Archaic period. The burial took place in an unlined pit, with the skeleton arranged on its left side in a semi-flexed position. Thirty-eight stone knives were included in the burial as an offering. The University of Colorado osteology lab found that the skeleton belonged to a young man in his twenties who was about five feet three inches tall. Aside from the skull, the bones were not in good condition, and the cause of death could not be determined.