The evidence for these much-earlier dates consists of the bones of black bear and two species of deer which appeared in middens associated with 22,000-year-old hearths, as well as a curved obsidian blade which was found beneath a buried tree trunk. The bones were 24,000 years BP (± 4000 years) and 21,700 years BP (± 500 years). The obsidian blade was found under a tree trunk which dated to 24,000 years BP (± 1000 years) and was itself dated, using the obsidian hydration method, to between 21,250 and 25,000 years BP.