The chronology and distribution of ground stone artifacts on Santa Rosa Island, California.

Recent research on California’s Northern Channel Islands has emphasized the dietary importance of terrestrial resources, but less attention has been paid to the use of ground stone artifacts, which were often used to process plant-based foods. This is in contrast to chipped stone technologies, namely chert microblades/microdrills and early Paleocoastal points, which have been the subject of extensive archaeological research. In this study, we used records of archaeological sites on Santa Rosa Island, a GIS database of site locations, and chronological indicators to compile data about the timing and geographic variation in ground stone abundance across the island. We found that nearly 25% of sites on the island with records contain ground stone, and it remained important from the Middle Holocene (8200–4200 cal BP) until the time of Spanish contact. Overall, interior sites are more likely to contain ground stone than coastal sites, but they have fewer pieces per site on average. Additionally, bowl mortars and pestles are more likely to be noted for sites than metates or grinding stones and manos, although there does not appear to be large chronological variation in the relative frequency of these tool types. By better understanding the chronology and distribution of ground stone on the Northern Channel Islands, it is possible to develop a more complete picture of the role of terrestrial resources in island diet and the nature of population settlement and movement between the coast and interior of the island as social complexity increased during the Late Holocene. [ABSTRACT FROM AUTHOR]