The Black Mesa Archaeological Project has been conducting field investigations and archaeological research in northeastern Arizona since 1967. The work is contracted for by Peabody Coal Company in order to comply with federal, state, and tribal statutes. The longevity of the project, as well as its size and complexity, affords a unique opportunity to evaluate and refine research, project administration, and legal compliance procedures. In most situations, clear advantages have resulted from the opportunities to learn from the project's history. Unfortunately, changing statutes and changing interpretations of the same statutes have resulted in major problems—both for the archaeologists and for the Peabody Coal Company.

The results of a study on the relationship between stylistic variation in Kalahari San projectile points and aspects of San social organization are summarized. Five issues relevant to archaeology are discussed in light of the San data: (1) stylistic behavior and the different aspects of style, (2) which items of material culture carry social information and why, (3) which attributes on San projectile points carry social information, (4) what the results of the analysis of stylistic variation in projectile points imply for current methods of stylistic analysis and interpretation, and (5) the correspondence between style in San projectile points and San organization.

Conspicuous disturbances in archaeological sites are readily detected during excavation. However, one animal whose destructive effects are not often recognized is the earthworm. Work at the Carlston Annis mound in Kentucky, an Archaic shell midden, has resulted in the identification of areas of extensive earthworm disturbance. Archaeological sites most readily affected are those with the appropriate vegetation cover, moisture and temperature conditions, and available chemical elements. The type of disturbance a site will undergo depends on the species of earthworms present. Subsurface-casting species mix matrix only below the surface while surface-casting species bring the fine-grained matrix to the surface, thus concentrating larger objects below ground. If earthworm casts are identified in a profile, one should proceed cautiously with interpretations concerning soil matrix.

Tree-ring data from the Canyon Creek Ruin, east-central Arizona, are analyzed to evaluate two competing interpretations of pueblo growth at this well-preserved cliff dwelling. Despite an anomalous dating pattern, a logistic model best describes pueblo growth. Room construction activity is linked to population increase, which, in turn, may be divided into two varieties: natural increase, and immigration of households into the settlement. Logistic growth also accounts for population increase within the larger area of the Grasshopper region. I review the processes promoting both local and regional population increase, as well as subsequent abandonment of the mountains of Arizona. I suggest that rapid depopulation may have occurred after A.D. 1375 because late prehistoric communities lost access to nonlocal goods that had previously allowed populations to increase beyond local resource constraints.

Weathering of hydroxyapatite, Ca5(PO4)3(OH) in bone probably is initiated by organic and carbonic acids formed by the microbial decomposition of collagen. This weathering, independent of soil properties, is caused by protons replacing Ca from hydroxyapatite. As collagen is depleted, proton production decreases and weathering may either continue if protons are available from the soil or be arrested if Ca from the soil displaces the protons previously added to the hydroxyapatite. The theoretical Ca/P weight ratio of unweathered bones is 2.15. Weathered bones that have been stabilized by Ca may have this ratio or a higher one if extra Ca has been added. A group of weathered bones from one site with a slightly acid soil had an average ratio of 1.67, which probably promotes further weathering, while bone at the same site with an average ratio of 4.09 was less weathered and apparently stabilized.

For the determination of provenience of obsidian artifacts, precise and accurate measurements of composition patterns of the geologic sources are necessary for definitive and cost-effective assignments. Inter-comparison of data from different laboratories is often difficult. Suggestions for maximizing the usefulness of data already in the literature are made, contributions to a useful data bank of source composition patterns are recorded, and provenience determinations of 30 artifacts excavated in Quirigua, Guatemala are presented to exemplify the technique.

A phonetic and semantic interpretation of the directional glyphs in Maya inscriptions and codices reveals that they did not refer to the cardinal directions. The glyphs that have been identified previously with north and south can be read phonetically as zenith and nadir, respectively. The glyphs for east and west refer semantically to the rising and setting sun. These data support Clemency Coggins's recent suggestion that Classic Maya directional symbolism was related to the path of the sun across the sky and through the underworld, rather than to the cardinal directions.

A second amber source has been discovered in Chiapas, which is important for considerations of prehistoric exchange. Source analysis is discussed as a possible means of distinguishing prehistoric amber from the two known sources.

The National Register of Historic Places is important to the preservation of prehistoric sites in ways that are not fully appreciated by archaeologists. The advantages of having a site on the Register are discussed. Archaeologists have a responsibility toward site preservation, and the use of the Register is one means to fulfill that responsibility.

Ortloff, Moseley, and Feldman fail to understand the basics of canal hydraulics and irrigation hydrology. They estimate nonpermissible velocities, calculate a critical state of flow, and assume a discharge without considering the field requirements. Their claim that tectonic movements caused canal abandonment is rejected. There is no geomorphological evidence for such events. Other research is described which indicates that the canal was designed with a stable channel and was intended to transport the required discharge to state fields. Its breakdown is attributed to the effect of a large discharge flowing down a steep slope.

Antithetical premises of a static versus dynamic Andean landscape produce contradictory interpretations of the Chicama-Moche Intervalley Canal. On a static landscape, inoperable canal gradients must be explained by social parameters such as poor surveying or construction techniques. The paradigm of Plate Tectonics and evidence of ongoing crustal convergence support an alternative premise of continuous, gradual landscape alteration and ground slope change. This premise provides a physical explanation for why abandoned canals often exhibit uphill gradients and ancient monuments are frequently not level. However, this premise also requires that complex methods in the engineering analysis of slope-altered structures be made explicit. Assessment of landscape alteration utilizes basic principles of physical geology, but their application to a particular study area must take local conditions into consideration. Similarly, analysis of the hydraulic properties of an irrigation canal utilizes basic principles of fluid dynamics, but local conditions must be considered in deciding which formulas to use and how to apply them. Improper application of geological principles and hydraulic equations has led our critics to incorrect results.

This paper presents a critical assessment of Killingley's approach to the determination of month of collection of marine molluscs by prehistoric people. The basis of the method is careful oxygen isotope measurements made in successive growth increments in the shells. We have analyzed specimens of Monodonta and Patella collected live on the coast of northern Spain, in conjunction with seasonality studies on molluscs from prehistoric sites in the neighborhood. These studies confirm the necessity of making careful analyses of each species under consideration. Given the significance both of interspecies differences and of climatic variability on timescales from a year upwards (particularly important in Killingley's area), we conclude that his apparent accuracy of ± a month is illusory.

A response is presented to the comment by Bailey et al. on the determination of seasonality of mollusk collecting using O-18 profiles of midden shells. Profiles were measured on two species of intertidal mollusks (Tegula funebralis and Collisella limatula) to provide further evidence for the applicability of the technique to seasonality studies.