The Value of Pismo Clam Tube Beads in California: Experiments in Drilling

Shell beads have long been a topic of interest in North American Pacific Coast archaeology. Studies by Gifford (1947), Gibson (1975, 1976, 1987, 1992), King (1974, 1978, 1990), Macko (1984), Bennyhoff and Hughes (1987), Arnold (1992a), Arnold and Munns (1994), and Arnold and Graesch (2001) have established the temporal sensitivity of shell bead assemblages in California and explored their socioeconomic importance among several groups on the coast and in the interior. Somewhat less attention has been directed toward elucidating shell bead production techniques (but see Arnold and Graesch, 2001; Macko, 1984). Here, we experiment with an often reported but unusual drilling technique attributed to the coastal Chumash, among others, for the manufacturing of Pismo clam (Tivela stultorum) tube beads. We also place Tivela stultorum bead manufacturing in a broader cultural and manufacturing context, including implementing systematic Moh's hardness testing of Tivela and nine other widely used shell species. Ethnographic, archaeological, and experimental evidence suggests that Tivela tube beads were among the most labor-intensive and valuable of the many bead types made and used by Native Californians.