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Anthony A. Vega

Archaeological Investigations of San Lorenzo’s Northern Alluvial Floodplain
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Figure 1. Olmec Archaeological Sites in Southern Veracruz and Eastern Tabasco, México.

Research Year:  1998
Culture:  Olmec
Chronology:  Pre-Classic
Location:  Veracruz, México
Site:  San Lorenzo

Table of Contents

Research Objectives
Field Methods
Summary of Test Excavation Results
List de Figures
Sources Cited


The Olmec center of San Lorenzo is situated atop a large plateau located within the lower drainage system of the Coatzacoalcos river basin in southeastern, Veracruz, México (Figure 1). There the San Lorenzo plateau rises 50 meters above the surrounding floodplains. A complex pattern of ancient and modern meanders and oxbow lakes characterize the floodplains, indicating a continual change in hydrology. More importantly, the floodplains contain a pattern of low mound sites that vary in size, form, and height. The arrangement and location of the mounds is also variable. They occur in isolation, in groups of two, three, four or five around or near the ancient and present river channels. In some cases, the mounds are located next to or separated by low depressions that also vary in depth and size. The majority of the low mound sites occur within the alluvial floodplain north of the San Lorenzo plateau (Figure 2). This floodplain comprises at least 23 square kilometers of San Lorenzo’s inner hinterland. Natural boundaries define the northern alluvial floodplain. The Tatagapa River and its tributaries; the Tatagapilla, the Largatero and the Paseo Arena Arroyo, define the western boundary. The Chiquito River defines the eastern boundary. The junction of the Tatagapa and Río Chiquito Rivers define the northernmost boundary; whereas an arbitrary east-west line north of the San Lorenzo plateau, extending from the Tatagapa River to the Chiquito River, represents the southern boundary (Figure 2 and Figure 3).

A recent archaeological survey identified 106 low mounds in the surrounding floodplains, seventy of which occur in the northern floodplain (Lunagomez, 1993; 1995). In 1993, Cyphers investigated one of the low mound sites within the northern floodplain and uncovered seven fire pits within a six square meter area. Analysis of the ceramic material recovered from the associated stratigraphic layers have placed those fire pits within the Early Formative Period (1250 to 900 B.C.) (Cyphers, 1993; Lunagomez, 1995; Symonds, 1995). In 1998, I carried out an initial survey in the northern floodplain and determined that number of mounds is closer to 100. I also carried out test excavations at 15 of those low mound sites from February 28 to May 29, 1998. This archaeological research was carried out under the auspices of the San Lorenzo Tenochtitlán Archaeological Project with the permission of the Consejo Nacional de Arqueología of the Instituto Nacional de Antropología e Historia in México. The Foundation for the Advancement of Mesoamerican Studies Incorporated funded this archaeological research. This report is a summary of the methods and results of the excavations carried out during the three-month period of excavations.

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Submitted 12/01/1999 by:

University of Illinois at Urbana-Champaign

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