Abstract
Population movements in prehistoric California have been difficult to decipher, none more so than the so-called Meganos Intrusion hypothesized by James Bennyhoff in 1986. This Intrusion described the westward expansion (ca. 500 A.D.) of a Penutian-speaking proto-Miwok group out of California’s San Joaquin Delta into the East Bay and then southward into the Santa Clara Valley. Lasting perhaps two centuries, the Meganos Intrusion was itself displaced by another population movement from the north. Returning to the Delta, the Meganos became the ancestors of the Plains Miwok and/or the closely related Yokuts. Bennyhoff’s hypothesis was largely based on differences in material culture, grave goods and burial positions. A difference in physical type noted by several researchers has never been subjected to osteological analysis. In this study, a meta-analysis of cranial data from six sites associated with or contemporaneous with the Meganos Intrusion examined both craniometric and discrete traits in order to obtain estimates of biological distance between these groups. One site, CA-ALA-343, yielded some burials exhibiting Meganos characteristics and others with non-Meganos characteristics. This data was divided into test cases according to burial position. The vi results were compared with data from two contemporary non-Meganos sites in the Santa Clara Valley (CA-SCL-137 and CA-SCL-674) and three Central Valley sites linked to groups considered possible ancestors (CA-SJO-091) or possible descendants of the Meganos (CA-SAC-117 and CA-SJO-105). Craniometric analyses were inconclusive. Nonmetric trait frequencies, however, show that burials demonstrating Bennyhoff’s Meganos characteristics at CA-ALA-343 are indeed more closely related to all three Central Valley sites, while the non-Meganos burials are more closely related to those at the Santa Clara site, CA-SCL-674. The other Santa Clara site, CA-SCL-137, appears to be distinct from all of the other groups.