Tepetlaoztoc Project: Archaeological Investigations

Results of the Pilot Project

I spent approximately one month at Tepetlaoztoc, in August of 1995, testing the feasibility of a household archaeology project. The original plan was to use funding from the Foundation to resurvey the area around Tepetlaoztoc and assess the present day condition of the area sites. If the preserved remains of residential structures, mapped by Parsons as part of his Texcoco Project (Parsons, 1971) were adequate for sampling, the resurvey would serve as an initial stage of a large excavation project to be funded by the National Science Foundation next year. I suggested a project at Tepetlaoztoc for two reasons:

1. Parsons located over 400 residential mounds in his survey of the town site, many of which had visible surface architecture in the form of wall lines on the surfaces of the mounds.

2. Two 16th century Codices, the Vergara and Santa María Asunción, were among the most detailed censuses taken by the Spaniards dating from the 1540s, and provide data on household size and composition of one of the barrios of the town of Tepetlaoztoc. The Codices even include data on land holdings for each household and types of soil found in the land holdings, an extremely rare element in the early Spanish census.

3. Because of these two resources, the site seemed ideal to conduct a large number of excavations in Aztec residences to provide information on a number of questions raised by recent ethnohistoric research on the Post-Conquest situation. Our experience in excavating Aztec residential sites suggested that with a relatively small number of workers, over a short period of time, a large number of residences could be excavated during a single season, with a relatively modest budget. The situation, therefore, seemed ideal in terms of sampling problems.

Our concern with respect to preservation today of the sites surveyed by Parsons rested on recent developments in the Basin of México that are threatening much of the surface archaeology. The factors that threaten the sites are as follows:

1. The growth of México City from a city of 3,000,000 to over 20,000,000 people between 1950 and 1995. This is not a problem in Tepetlaoztoc, however.

2. Recent use of tractors and what are called chisel plows to work over the tepetate surfaces (a sub-soil consisting of compacted volcanic rock that can be pulverized and converted into a useful soil) in much of the badly eroded areas of the Basin. It should be noted that many Aztec house sites exist in these areas because they have been lost to cultivation, as the product of 16th and 17th century soil erosion.

The August survey confirmed our worst fears. In the area held by the barrio of Santa María Asunción as its agricultural land in 1540, Parsons located 200 residential mounds on the present-day severely eroded area north of Cerro Teponaztle, of which 112 were well enough preserved to provide information on household size and room arrangements, even from surface survey. These would have been ideal for large-scale excavation. All of this area, with the exception of one small locality on the northeast slope of the hill, has been extensively chisel plowed; a series of contour embankments constructed of the crushed tepetate; and a eucalyptus grove planted by the forestry department of the federal government, as part of their program of land reclamation. In this process all of the 200 mounds have been destroyed (see Figure 5a, Figure 5b, Figure 6a, and Figure 6b).

In the deeper soil areas in the valley east of the hill, still used for agriculture by the barrio, Parsons recorded 36 residential mounds. These areas have not been chisel-plowed because they have adequate soil depth, but two recent developments have left even these areas in poor condition, in terms of the archaeological remains. One is the extensive use of tractors and deep cutting plows, in the past provided only by a few private contractors and, hence, restricted in its use but now provided by the State of México at nominal charges to all of the municipios in the state. This has meant a great extension of their use and has resulted in much more massive destruction than the old Spanish plow, which was in exclusive use in the area as late as 1970 and was still extensively used as recently as 1985.

A second process is the conversion of much of the area today to nopal planting, a process stimulated by the growth of the México City fruit market. This involves considerable earth movement, including the construction of embankments for the planting of rows of nopal cactus. Complicating my survey in August, furthermore, was the presence of very high dense corn in the fields and extensive plantings of barley and wheat. Even considering these difficulties, I was able to establish the locality of many of Parsons’ 36 mounds and discovered that only a few were preserved and even these had suffered heavy damage (see Figure 7a, Figure 7b, Figure 7c, and Figure 7d).

I then examined the immediate periphery of the modern town of Tepetlaoztoc, an area not included in Parsons’ surveys. Most particularly I focused on those areas occupied by the modern barrio of Santa María Asunción. By approximately A.D. 1600 the Spanish crown had forced Aztec households, living in a dispersed settlement pattern, into more nucleated settlements. The present barrio of Santa María Asunción is the product of that resettlement program. Nevertheless, Tepetlaoztoc today is a relatively low density and somewhat dispersed town and many of the houses have relatively large lots (see Figure 3). These are used for farming small garden plots that are too small for tractor plowing.

In these areas I was able to find clear evidence of relatively undisturbed archaeological deposits but no clear evidence of surface mounds. The evidence of occupation was in light to medium concentrations of Aztec ceramics. In my resurvey of the area surveyed by Parsons on the valley floor I also found a number of undisturbed localities, where he did not locate house mounds but where surface occupation in the form of sherds was relatively heavy. In these areas household archaeology is still feasible and could be highly productive; however, the original reason for the selection of the Tepetlaoztoc site was the presence of a large number of surface mounds with room patterns easily visible. What this means is that the second phase of this project would be significantly more expensive than originally conceived. We would have to conduct an initial phase of test pitting to locate the house sites and then follow up successful results with larger scale excavations.

In May 1996, I returned to México for a week and spent several days to reexamine the deeper soil areas as confirmation of the destruction of the 36 mounds in those areas. Jeffrey Parsons accompanied me on one of my visits. The fields were then bare of vegetation and observation of surface remains more reliable. We discovered that some of the level fields near the barrancas often had areas of soil depths of less than 30 cm and the plow shares had shattered the tepetate surface below, as evidenced by the abundance of tepetate fragments in the soil. The fields also had scattered rock rubble from destroyed house mounds and left only concentration of sherds to mark the former mound sites (see Figure 7d). It was evident that few if any of the 36 mounds in this area were intact. A reexamination of the few fields that local informants indicated had not been tractor plowed on the eroded piedmont and had also escaped the reforestation program, revealed that at best, only remnants of residential mounds were still intact.

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