Located just north of Deer Creek in the valley between the hogback ridge and the foothills west of Denver, the Ken-Caryl South Valley Archaeological District contains rock shelters that were used by prehistoric peoples from at least the Late Paleo-Indian period (before 6000 BCE) through the Early Ceramic period (150–1150 CE). The Colorado Archaeological Society started excavations in the valley in the early 1970s, after Johns Manville acquired the area with plans to build a corporate headquarters and residential community. The northern portion of Ken-Caryl Valley was developed in the 1980s, but most of South Valley was acquired by Jefferson County Open Space in 1997.
Before Ken-Caryl Ranch
In 1859 or 1860, the Denver dry goods merchant Robert B. Bradford settled in what is now Ken-Caryl Valley. He built a house and established the Bradford Road Company, which surveyed a wagon road to the mines near Fairplay. Bradford’s road was rough, but it proved popular until 1867, when a new road in Turkey Creek Canyon drew traffic away. When Bradford died in 1876, he left his widow in debt. She eventually lost their house and 219-acre ranch, which passed through several owners in the next few decades.
In 1914, Rocky Mountain News owner John C. Shaffer bought the former Bradford ranch along with hundreds of adjacent acres. He named the ranch Ken-Caryl after his sons, Kent and Carroll. Shaffer lost the ranch during the Depression, and after changing hands a few times it was acquired by A. J. McDonald in 1949. McDonald used the land as a cattle ranch until 1971, when he sold it to Johns-Manville, an insulation and roofing company. The company built a large headquarters at the southwest end of the valley and moved there in 1974. In the rest of the valley, the company continued the existing cattle operation. It also formed the Ken-Caryl Ranch Corporation to develop its property on the east side of the hogback ridge.
South Valley Archaeological Investigations
Starting in 1973, Johns-Manville and the Ken-Caryl Ranch Corporation allowed the Denver chapter of the Colorado Archaeological Society to excavate sites in the northern portion of Ken-Caryl Valley, which was scheduled for future development. In 1976 the companies extended their permission to the southern portion of the valley, and archaeological work continued in South Valley through the early 2000s.
The prehistoric sites identified in South Valley were primarily rock shelters located at the base of the area’s large red Fountain Formation outcrops. Archaeologists suspect that all of the area’s red rocks were used as rock shelters, but only a few have been tested and excavated. The shelters contained evidence of repeated occupations, probably from fall through spring as part of an annual migration that included summers spent in the high mountains. The area would have been an attractive winter camp. In addition to the valley’s relatively mild conditions, the southwest-facing shelters would have provided warmth from the sun and protected inhabitants from snows and north winds. It is also possible that some groups lived year-round in the valley and the nearby plains.
The investigations at South Valley supported the foothills chronology derived from earlier excavations such as Magic Mountain and LoDaisKa. Although archaeologists recovered a few artifacts suggesting Paleo-Indian habitation as early as 7500 BCE, most of the evidence dated from the Middle Archaic period (3000–1000 BCE) to the Early Ceramic period. Use of the valley increased over time, with occupations in the Ceramic period probably involving some combination of more people, longer stays, or more intensive use than earlier Archaic period occupations. Puzzlingly, given the gradual increase in deposits from the Middle Archaic through the Early Ceramic, little evidence remained from the period after about 1000 CE. A drought may have driven people away from the hogback valley, or erosion could have carried away the evidence of more recent habitations.
In 1980 Johns-Manville and the Ken-Caryl Ranch Corporation began work on a new residential development in the northern portion of Ken-Caryl Valley. Because of the excavation work that had already been completed in that part of the valley and the cooperation of the developers, many of the area’s archaeological sites were preserved in greenbelts and open spaces.
In 1982 Johns-Manville declared bankruptcy because of asbestos-related litigation. In 1987 Martin Marietta (now Lockheed Martin) acquired the former Johns-Manville headquarters and hundreds of acres of land in South Valley. Lockheed Martin began to move forward with existing plans to develop South Valley as a residential community similar to what had been built in the northern part of the valley.
Facing opposition to the development, Lockheed Martin gave Jefferson County Open Space the chance to acquire the property for preservation and recreation. In 1997 Jefferson County Open Space bought the 895-acre South Valley Park, which includes most of the area’s archaeological sites, and hired Paragon Archaeological Consultants to conduct a complete survey of the valley’s cultural resources. In addition, in 1997 the Colorado Archaeological Society published a monograph about its work in Ken-Caryl Valley, and it has continued to conduct investigations in South Valley.