Roasting Pits
Roasting pits: compact areas that are distinguished by the presence of charcoal, ash, fire-affected rocks, and evidence of subsurface disturbance — occur in large numbers in the eastern foothills of San Diego County (Cook and Fulmer 1980; May 1987; Wallace and Taylor 1958). Such features are commonly interpreted as earth ovens in which Agave deserti was roasted. A substantial body of ethnographic testimony supports that interpretation (e.g., Bean and Saubel 1972; Castetter et al. 1938; Chase 1919; Cuero 1968; Gifford 1931; Hicks 1963; Lee 1937).
There is also some ethnographic evidence for the pit-roasting of other resources. Materials that have been specifically mentioned in the ethnographic literature as having been cooked in earth ovens include meat, Yucca whipplei, Nolina bigelovii, mesquite (Prosopis juliflora), beavertail cactus (Opuntia basilaris), cholla (Opuntia bigelovii), barrel cactus (Echinocactus acanthodes), saltbush (Atriplex spp.), Mariposa lily (Claochortus spp.), desert lily (Hesperocallis undulata), bladder pod (Isomeris arborea), and pine nuts (Barrows 1900:59, 67; Bean and Saubel 1972:50, 68, 77, 79, 94-96, 108, 150; Castetter and Bell 1951:188-189; Curtis 1900-1930:vol.15:24; Drucker 1937:10, 1941:101; Gifford 1931:24; Hicks 1963:114-115, 124, 154-155; Saunders 1914).
M. Steven Shackley (1983, 1984) formulated the problem of the diversity of roasted materials as a research domain for archaeological excavations of roasting pits. He hypothesized that roasting pits located in temporary camps would show greater diversity in the materials processed than would isolated pits. Shackley recovered burnt animal bone from a roasting pit in southwestern Imperial County but was disappointed by poor recovery of identifiable floral materials.
Brian Williams (2014) investigated 130 thermal features at site CA-SDI-7074 in Jacumba Valley. Macrobotanical samples from 17 of the features included yucca, juniper, mesquite, saltbush, hedgehog cactus, and the mallow and rose families. Although the site’s environmental context fit well with the interpretation of the features’ use to process agave, the macrobotanical remains were not able to confirm that function.
Schaefer and Laylander (2014; Laylander et al. 2015) made a GIS-based study of archaeological sites in the Jacumba/McCain Valley region. A total of 157 sites were characterized as likely agave roasting sites, based on the presence of thermal features and the absence of substantial occupational debris or other features. The sites were found to be disproportionately concentrated within vegetation units in which agave was a notable constituent. Some of the thermal features were also found in contexts that suggested the processing of cactus fruit or mesquite.
PROSPECTS
Future archaeological investigations may be able to clarify the range and relative frequencies of materials cooked in roasting pits. Evidence relevant to these issues may include floral and faunal materials recovered by excavations and the analysis of the associations between roasting pit locations and modern biotic communities.