During the time of the Paleo-Indians, around the late Pleistocene to early Holocene geological periods, the areas between 400 and 500 meters above sea level formed a microclimate in which the canyon was home to grasslands hospitable to the animals that lived in it. This microclimate included the schinus molle plant, which was useful to native inhabitants for its ability to form resins and adhesives, as well as its use as a source of firewood. The climate was also home to edible vegetables and plants that could be used for medicine; tubers, such as the rush root; and numerous fruits, such as that of the berberis plant.
