The Significance to California Prehistory of the Earliest Mortars and Pestles

At the time of initial contact with European colonists, most California native groups used stone mortars and pestles for milling acorns into flour. The prevalence of these implements in aboriginal California generally reflects the considerable significance of acorns to the aboriginal diet. Mortars and pestles have a long prehistory in California, and as Basgall (1987) has pointed out, their initial use and increasing importance through time reflects subsistence intensification in that acorn processing requires considerable labor investments, much more per unit of food value than many other plant foods.