and the determination of distributions of ethnic or linguistic groups and of patterns of migration into the country throughout its history.

Archaeological sites in El Salvador were noted by a number of the visitors, including E.G. Squier and the Germans K. Sapper and S. Habel, who passed through the area in the mid- to late nineteenth century as commercial schemes were being developed in the newly independent Central American republics. The reports of these foreign visitors were followed by local explorations, and in 1944, archaeologist John Longyear noted that “to date, practically all the archaeological work in El Salvador had been carried on by private citizens of that country, notably the owners of estates containing ruins of various types.” The collections amassed in this fashion were sufficient for Atilio Peccorini to publish a preliminary article in Spanish in 1913 on the general outlines of Salvadoran archaeology.

Attention from professional North American archaeologists quickly followed, and in 1915, H.J. Spinden published an English summary drawing on material in private collections. In keeping with his broad conceptual scheme for the development of civilization in Central America, Spinden classified remains as archaic, Mayan, and aztec. His archaic period was marked by solid, hand-modeled figurines and the pottery later named Usulutan resist. He identified as Mayan those pottery vessels painted with figural and glyphic motifs. He interpolated a third period of occupation between the Maya and Aztec occupations of the country, the latter identified with the Pipil people noted in sixteenth-century Spanish accounts. Later research by North American archaeologists in El Salvador, while modifying the terminology used by Spinden, essentially assumed the same scheme with its implication that the country was subject to periodic population displacements.

Stratigraphic support for both the general occupation sequence proposed by Spinden and the idea that populations had been displaced and replaced came from the documentation of volcanic ash separating different cultural deposits. The Salvadoran Jorge Lardé first reported this situation in 1924, and in 1926 he and Samuel K. Lothrop investigated the phenomenon at Cerro Zapote. There they described two layers of cultural material separated by volcanic ash. The lower corresponded to Spinden’s archaic period while the upper included painted pottery classified as Maya, effigy vessels identified with the Pipil, and the pottery type Plumbate, which Spinden had identified as being typical of the intervening period. An admixture of archaic materials was also present in the upper layer. Lothrop’s interpretation of the upper layer was that it indicated, at least in part, that all three of Spinden’s periods overlapped each other. Lothrop’s report paid no apparent attention to the possibility of stratification within the deposits sealed by the volcanic ash.

Field-workers who immediately followed directed their attention to exploring individual sites with obvious architectural remains and mounds in loosely arranged groups. On investigation, many sites proved to be constructed of materials that appeared anomalous when compared to the cut stone and plaster of the Mayan centers. Quelepa had been subject to early exploration by Peccorini, and in 1929, Antonio Sol, director of the Department of History of guatemala, conducted the first government-sponsored excavations on the site of Cihuatan in central El Salvador. The cut stone architecture, pyramidal temple, ball court, and walled plazas conformed to patterns known from sites to the west and north. A decade elapsed before further professional fieldwork was initiated. In 1939, the Middle American Research Institute and the Carnegie Institution of Washington (CIW) expanded their programs of Mayan research into western El Salvador through excavations at the site of Campana San Andres directed by John Dimick, assisted by Stanley Boggs. Campana San Andres, according to Boggs (1950), was constructed of adobe with a thick cement facing, features he compared with the highland Maya site Kaminaljuyu recently excavated by the CIW. Boggs defined a series of four construction phases at the site, all associated with Mayan-style pottery, and argued for a short period of occupation at Campana San Andres and cultural identity with Maya-speaking peoples.

Further research on architectural centers in the country was carried out in 1941 and 1942