Human prehistory in southern Mendocino County extends back at least 10,000 years. The use by these people of the property occupied presently by HREC was intensive. Nearly thirty archaeological sites have been identified, seventeen of which have been recorded at the Archaeological Inventory Northwest Information Center at Sonoma State University. The most extensive site (MEN-852) lies along the perennial sag ponds in Lake Biological Pasture. At least two, and possibly four, house pits were identified at this site, and there is an extensive surface scatter of obsidian and chert flakes and tools. This was indicated to be a "potentially productive" study site by Robert Orlins of the University of California, Davis. In addition, five petroglyph sites, two chert quarries, and a number of smaller habitation sites have been identified. There also exists an extensive collection of surface-collected artifacts donated by Center staff over the years. These consist largely of obsidian and chert tools and a broad array of points, but also include a variety of milling tools, clam shells and beads, soapstone pieces, and a schist pendant.
The study of these sites has been limited to rather general surveys. There has been no excavation of any of the sites to date. The Center would encourage and welcome the opportunity to have these cultural resources properly assessed and evaluated as part of a research project.