We have empirically tested and evaluated several astronomically related hypotheses about the ruins of Alta Vista near the modern town of Chalchihuites, Zacatecas, in Northwest Mexico. We conclude that the site was deliberately located and oriented astronomically by people of the Teotihuacan civilization.As supporting evidence we analyze (a) a double solar alignment incorporating a labyrinthine hallway at the ruins, and (b) a pair of circle-shaped markers, of a type found at Teotihuacan, pecked into a flat stone on a hilltop to the south. The former can be correlated with an equinoctial sunrise observation and the latter with a summer solstice sunrise, each over the same distant peak. Furthermore, a detailed examination of the pecked petroglyphs reveals that they may have served as time-marking devices.

In the Edwards Plateau and Trans-Pecos regions of southwestern Texas are a large number of archaeological sites which have been referred to as “burnt rock mounds.” Although this name is now well established in the archaeological literature of Texas, one looks in vain for a satisfactory statement concerning the origin and nature of these rather unusual sites. Quite a number have been excavated, but as yet few detailed reports on individual sites have appeared. The authors of recent reports assume that the term “burnt rock mound” is well understood and, although implying that it represents a distinct culture trait, do not explain what it means. It is evident that many archaeologists do not understand its meaning, for at recent archaeological meetings outside of Texas the writers of this paper have frequently been asked, “Just what is a burnt rock mound?” In view of this, it seems advisable to put on record a brief summary of what is known at present about the formation of these sites.

An archaeological sequence for the Sinaloa coastal strip of western Mexico had previously been developed by Sauer and Brand, Isabel Kelly, and Gordon Ekholm. Investigations carried out by Southern Illinois University and associates from 1952 to 1958 in Durango, across the Sierra Madre Occidental to the east of Sinaloa, have established an independent archaeological sequence. The presence of trade pottery and other artifacts from Sinaloa in the Durango sites makes possible an independent check of the Sinaloa sequence. This cross correlation essentially confirms the basic Sinaloa sequence of (early to late) Chametla, Aztatlan, and Culiacan periods, but indicates that there is some overlap between these major horizons and that the Aztatlan period is actually divisible into three more or less sequent phases: an early Lolandis phase, an intermediate Acaponeta phase, and a terminal Guasave phase. Re-examination of the Sinaloa sequence confirms and expands these conclusions, resulting in this revision of the archaeological sequence for Sinaloa. For consistency, a revised terminology for the various phases is also presented.

The importance of the Clear Fork Focus as a pre-pottery archaeological complex of north-central Texas has become generally known to archaeologists through the industry of its discoverer and principal proponent, Dr. Cyrus N. Ray, of Abilene, Texas. Unfortunately, the relationship of this complex to other and comparable archaeological cultures of Texas has been largely neglected and some regrettable misinformation in regard to its chronological position has been widely disseminated. In this paper the cultural affiliations and age of the Clear Fork Focus will be discussed in terms of the evidence presented by its discoverers and from the standpoint of new data derived from large scale excavations completed by the University of Texas in the terraces of the Colorado River near Austin, Texas. Additional information obtained by the writer through study of some twelve thousand projectile points from central, south, and western Texas, and their geographic and temporal distribution also is used.

One of the seminar topics scheduled for the summer of 1955 by the Society for American Archaeology was “The American Southwest: A Problem in Cultural Isolation.” The assignment was to “… examine the assumption that these Southwestern cultures resulted from local acceptance and development of generalized and/or specific traits which can be isolated in distant cultural contexts at earlier times than their climactic developments can be observed in the Southwest.”