Late Holocene Landscape Use, Site Seasonality, and Settlement Patterns in San Francisco, California

Using paleobotanical and faunal materials from sorting of just 20 liters of midden from precontact site CA-SFR-230, radiocarbon-dated between 1480 and 330 cal BP, we explore how precontact people of the San Francisco Peninsula accessed plant and animal resources from different parts of the landscape across different seasons. Isotopic and microscopy results show that the majority of food items could have been sourced within just 2 km, and all within 8 km, of the site. Shoreline and estuarine habitats were used in winter and summer to harvest fish and shellfish, grasslands and wetlands were exploited in spring and summer, and riparian areas in summer for a range of plant products. Fall resources are conspicuous by their near absence. We suggest people were residentially mobile during the fall, relocating either to larger shell mounds, or to areas in the interior of the peninsula, as part of a fission-fusion settlement pattern.