COBBLE MORTARS/BOWLS: EVIDENCE OF PREHISTORIC FISHERIES IN THE SOUTHERN CALIFORNIA BIGHT (original) (raw)

The most common type of artifact described from the 110 prehistoric underwater sites recorded in the Southern California Bight is a small, portable mortar/bowl. Manufactured from water-worn cobbles that underlie beaches and erode from wave-cut terraces, the source materials include felsitic and scoriaceous volcanics, plutonics, and sandstones, depending on island or mainland locality. Methods of production are evidenced by partially worked specimens and manufacturing tools. Hammerstones, picks, and abraders were used for pecking, percussion flaking, and grinding to create the mortar interior concavity and shape the exterior. The relatively great labor investment in manufacture from dense materials and the large number of mortars at some sites suggest that mortars were important elements of subsistence strategies. Although mortars are often considered plant-processing tools, the proveniences of these nearshore artifacts suggest a different use. Mortars are found in shallow rocky reefs, kelp beds, and along the rims of submarine canyons. Since the Middle Holocene, these habitats have supported the most diverse and accessible fisheries of the Bight. We propose that the mortars described here were part of prehistoric fishing strategies, possibly involving chumming and/or fish trapping in conjunction with the use of watercraft.