The recovery of obsidian artifacts in radiometrically dated cultural stratigraphic levels at the Maya site of Cahal Pech (Belize) suggests that there was a flake-to-bladelet sequence of development of obsidian technology in the Belize Valley region of the Maya lowlands. Obsidian artifacts within levels dating to the first half of the early Middle Formative period (1000-850 B.C.) at Cahal Pech consist exclusively of flakes. Prismatic blades first occur in late Middle Formative (650-450 B.C.) levels, and remain the predominant artifact type throughout the subsequent Late Formative and Classic periods. This Middle Formative transition in obsidian artifacts has been recorded elsewhere in Mesoamerica, but the Cahal Pech data represent the first explicitly documented case of the developmental sequence in the central Maya lowlands.

Since the 1950s, a decline in stature has been offered as evidence of increasing nutritional stress in prehistoric Maya populations, particularly during the Late Classic collapse. A review of the extant skeletal data, however, reveals very inconsistent support for such a decline. The primary explanation for the variation may reside in the small number of skeletal series that have representatives of more than one time period. Other possible explanations include methodological problems associated with stature reconstruction, reliability in sex determination, and variation in health response according to site size and location.

Recent excavations at the Late Archaic Period (ca. 3000-1000 B.C.) site of Kilometer 4 on the far south coast of Peru exposed a burial containing the remains of a 45-year-old male. The individual was buried with an unusual assemblage of artifacts that includes bone and shell implements and elaborate and distinctive cotton textiles, as well as a complex of paraphernalia of which some items were apparently associated with the use of hallucinogenic or other substances. Auditory exostoses indicate that the individual had engaged in maritime activities, including diving. Semi-flexed, single interment burials such as this are well known from the coast of northern Chile, but the use of cotton during the Archaic Period on the coast of the south-central Andes has not been well documented in the past.

We have examined the role of long-distance trade in Prehispanic Ecuador using X-ray fluorescence (XRF) and neutron-activation analysis (NAA) of obsidian artifacts from the archaeological sites of El Inga, Chobshi Cave and Site OGSE-46 on the Santa Elena Peninsula. Results indicate that two geological sources east of Quito, Yanaurco-Quiscatola and Mullumica, were the principal source of raw obsidian at these sites. We situate our findings within a broader archaeological context through a review of the literature and a discussion of an earlier provenience study undertaken by us. We express concerns about recent attempts to apply ethnohistoric models to early periods of Ecuadorian prehistory, and argue that despite early exploitation of the principal obsidian sources, long-distance trade in obsidian was initiated at a relatively late date and remained at a surprisingly low level in southern Ecuador during most of prehistory.

A study by neutron activation analysis and X-ray fluorescence measurements of 116 Ecuadorian obsidian artifacts as well as primary and secondary source samples has shown that the material originated from two Andean sources in north-central Ecuador, a flow in the valley of Mullumica, and deposits found on Yanaurco Chico and the nearby Quiscatola crest. The Yanaurco-Quiscatola deposit complex, homogeneous within our ability to measure, is represented by 18 percent of the artifacts. The Mullumica source has variable, apparently linearly related element abundances that may have resulted from the incomplete mixing of two magmas within a magma chamber. Seventy-eight percent of the samples studied are deduced to have originated from that source. Five artifacts from La Chimba cannot be assigned an origin, but four of them have the same provenience. To test the validity of the mixed-magma theory, we present equations to calculate the abundance of any measured element from that of iron. On the average, agreement within about 3 percent is obtained for artifacts.