The La Playa Archaeological Project: Binational Interdisciplinary Research on Long-Term Human Adaptation in the Sonoran Desert

Introduction

The La Playa site has a long and storied history in the archaeology of northwestern Sonora. This site was initially visited and described by Carl Sauer and Donald Brand as their Site No. 19 Boquillas during their pioneering reconnaissance conducted in 1930 with the objective of defining the southernmost extent of red-on-buff wares (Sauer and Brand 1931: 93–94). These self-styled “archaeogeographers” were struck by the massive sheet-flood erosion of the floodplain that was ubiquitously evident, along with the great amount of rocks, suggesting that “there are far too many stones and the individual heaps are too large to lend weight to the notion of their use in fireplaces”; importantly, they also noted that water was flowing with minnows and water plants present in the Boquillas arroyo (Sauer and Brand 1931: 93). Sauer and Brand (1931: 94) also commented on the large pestles present in the artifact assemblage, suggesting a dependence on mesquite or other gathered seeds, and noted the presence of Glycymeris bracelets along with hundreds of the cores produced in their production. This same year, Howard Scott Gentry reportedly collected the remains of Pleistocene fauna, including Platygonus, Bison, Capromeryx, Equus, camelid, and deer from this locality (White et al. 2010: 61). In 1935, Arthur Woodward (1936) was the first to apply the name “La Playa” to this site, which he described as being a “shell bracelet manufactory,” and concluded that it was an important locus in the production of shell ornaments for exchange. Julian Hayden (p.c. 1992) visited the site in 1935 as well. Gordon F. Ekholm provided a reasonably detailed description of the artifact assemblage at La Playa in late November 1937 (La Playa, Site No. 8) during the initial phase of the Archaeology of Sonora and Sinaloa Project conducted for the American Museum of Natural History under the direction of George Vallaint; numerous projectile points and decorated ceramics were also collected, and Ekholm observed that “there has seemed to be no possibility of learning anything from excavation, as the gullies in most parts of the site show nothing washing out at any depth” (Ekholm n.d.: 5). Ekholm also observed nothing which he considered to be diagnostic of the then recently defined Cochise Culture, but noted that the mano and metate types may indicate an early occupation (Ekholm n.d.: 5).

During Emil Haury’s tenure as head of the Department of Anthropology at the University of Arizona, he led students on frequent field trips to the La Playa site. In 1960, Alfred Johnson completed his master’s thesis entitled “The Place of the Trincheras Culture of Northern Sonora in Southwestern Archaeology” based primarily upon limited reconnaissance and excavations conducted at La Playa, concluding that this site was predominantly associated with the Trincheras archaeological tradition between 700 and 1100 CE, and reinforced his mentor’s perspective (Haury 1950: 547) that this tradition represented a “desert branch” variant of the Hohokam (Johnson 1963: 182–185). Additionally, Beatriz Braniff, who along with Arturo Oliveros had established the Centro INAH Sonora in 1973, visited the site several times between 1975 and 1980 and, as did Woodward, believed that La Playa represented a shell manufacturing site and was also likely an important node in the long-distance exchange route.

In 1992, the senior author, while a graduate student in anthropology at the University of Arizona, began efforts to relocate the site; that May, accompanied by Jonathan Mabry, the location of the La Playa site was confirmed. Subsequent frequent visits indicated that La Playa contained a complex assemblage of artifacts, features, human remains, and Pleistocene fauna. Moreover, the artifact assemblage indicated a primary affiliation associated with the Archaic and the then recently defined Early Agricultural period, and not the Trincheras tradition as had been previously proposed (Johnson 1960, 1963).

The La Playa site reflects an archaeological landscape encompassing 10 square kilometers located in northern Sonora, Mexico, and reveals archaeological evidence of more or less continuous human use since the Paleoindian...