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UA-1 Excavations

Submitted by mccaffer on Fri, 02/08/2008 - 6:37pm

By Geoffrey McCafferty (2008)

The UA-1 excavation was conducted as an archaeological field school by the University of the Americas (now the Universidad de las Américas) in the summer of 1968. The University at that time was located in Mexico City, and was primarily an English-speaking institution with a majority of North American students. The field school was conducted as a salvage operation prior to the construction of the present campus located on the outskirts of Cholula, Puebla.

The excavation was directed by Daniel Wolfman, Assistant Professor of Anthropology at the University of the Americas. Wolfman was a graduate student from the University of Colorado, in the process of finishing his dissertation on the use of archaeomagnetic dating in Mesoamerica. Wolfman was assisted by two graduate students (Marshall Beach and Jane Walsh), 18 students enrolled in the field school, and  there were ten local workers.

The field season consisted of one week of orientation prior to field work, four weeks of excavation, a week devoted to finalizing field work and checking field notes, and four weeks of laboratory analysis. Details of the excavation and preliminary lab results were described in Wolfman's (1968) Preliminary Report on Excavations at UA-1, July 1968.

This section describes the excavation methodology and presents a summary of results based on the preliminary report supplemented with information from the original field notes and other project documentation. Results of the excavation included the identification of three structures dating to the Classic and Postclassic periods. Additional features were also found, including burials, wells, trash deposits and isolated walls. 


Research Methodology

A preliminary survey of the University grounds revealed a concentration of surface artifacts in the southwestern portion of the campus. The project area was located from 5 to 40 m south of Building 5, Apartments B and C, of the original faculty housing area, and from 2 to 60 m east of the campus boundary fence (Peterson 1972:36). An area of about 50 m2 was cleared, and a grid was established at two meter intervals. The grid was oriented at 15 degrees east of magnetic north, aligned with a road that passes to the south of the project area. This orientation was used on the assumption that it was an ancient road, and that archaeological structures would conform to a similar directional pattern (Wolfman 1968:1).

The grid system was numbered relative to a central axis of north/south and east/west base lines; for example, the first square north and east of the axis was labelled N1/E1. Additional squares were numbered sequentially as they moved away from the axis; for example, N2/E1, N3/E1, etc. Note that the grid numbers were based on the number of grid squares rather than metric distance from the axis.

Although the grid was divided into 2 m squares, the actual excavation units measured 1.5 x 1.5 m, located in the center of each grid square. The intervening balks between the excavation units were left intact as a record of the stratigraphy until the units were completely excavated and profiles were drawn. In some cases the .5 x 2 m balks were then excavated in order to expose architectural features. Additionally, two trenches were excavated that did not conform to the grid plan to follow exterior stone walls.

A total of 67 units, 52 balks, and 5 sections of trench were excavated, totalling approximately 210 m2. Most units were excavated either to sterile soil or to the level of the first floor contact (usually between 60 and 80 cm below the surface). Some pits were dug below the stucco floor for a more detailed exposure of the stratigraphy and to sample deposits predating the floors. Others followed intrusive deposits such as burial pits.

The project area had been subject to agricultural plowing (probably non-mechanized) prior to excavation. Consequently, the upper soil level was disturbed to a depth of at least 25 cm. Other post-depositional disturbance included rodent burrows, wells, and trash pits. Below the plow-zone in many of the excavated units was a layer of collapsed adobe, representing the remains of former structures. Sterile subsoil was usually encountered between 120 and 140 cm below the surface. It was described as a "black grunge," suggesting that this may have been periodic wetland associated with the swampy lake located on the northern edge of the campus (Mountjoy and Peterson 1973:13-19).

The excavation of each unit proceeded by artificial 25 cm levels unless a distinctive soil change was detected. The usual practice was to excavate a "peek hole" in the corner of the unit to examine the stratigraphy prior to excavating each level. In many cases the peek hole encountered evidence for plaster or packed-earth floors in what would have been Level 3 (usually 50-75 cm below the surface). When floors were detected a "floor contact" level was separated and collected that included the cultural remains directly above the floor (usually 5-10 cm in thickness).

Artifacts that were identified in situ were triangulated and photographed. All soils from the excavations were sifted through 1/2 inch wire mesh, with cultural materials collected by level. In general, sherd bags were kept for each unit by level, with distinctions created if internal variations were recognized. For example, if a wall divided a unit, separate sherd bags were kept for each side of the wall. Provenience information on each pottery collection was recorded on Sherd Bag Cards. Lithic blades and debitage, and unworked bones were also collected in general bags by unit and level. Distinctive artifacts (such as figurines, spindle whorls, lithic tools, etc.) were separated at the time of excavation, bagged, and given object numbers (e.g., UA-1 #9100). Provenience information for general lithics, bone, and individual objects was recorded on Object Cards.

A preliminary analysis of the material remains was conducted during the final four weeks of the field school (Wolfman 1968). This included tabulations and more detailed classifications of different artifact classes. A ceramic analysis was done on approximately 40% of the total assemblage (Wolfman 1968:5) using categories from Noguera's (1954) classification, with other divisions based on vessel morphology, including bodies, rims, and supports.


Results and Preliminary Interpretations

The UA-1 excavations encountered the remains of three architectural compounds, as well as numerous features and abundant material remains (Fig. 1). The most extensively exposed architectural complex was Structure 1, which consisted of four complete rooms, several partially exposed porch areas, a patio with an associated midden deposit, and a small, oval enclosure. Structure 2 consisted of at least four partially exposed rooms and two possible porch areas, located about 10 m east of Structure 1. In the southwest corner of the project area a small portion of a stucco-covered platform was exposed, designated as Structure 3. In addition to these architectural units, other features included 19 human burials, three wells, and isolated features such as walls, walking surfaces and intrusive trash pits.

Figure 1. Map of the UA-1 Excavation Site


Information on the excavated features is primarily derived from the preliminary report (Wolfman 1968), with additional details included from the students' field notes, the Pit Summary Forms recorded for each unit, Feature Cards recorded for each feature, the Object and Sherd Bag Cards, and original photos. Several important document classes were missing at the time of my dissertation analysis, including Wolfman's personal field notebook, the field notes of the graduate assistants, pit profiles and related excavation plans, and approximately 250 of the Sherd Bag Cards. It was possible to reconstruct much of this missing information by cross-checking with the existing data. Nevertheless, significant gaps in the data existed, particularly in relation to site stratigraphy.


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