An Unexplored Realm in the Heartland of the Southern Gulf ... - Famsi

El Marquesillo’s geographic location on the San Juan River provided strategic
socioeconomic advantages. For people living in riverine environments, such as those in
the Tonala, Coatzacoalcos, Papaloapan, and San Juan River basins, it has been
established through archaeological and ethnohistoric data that water transport was the
most effective and efficient mode of conveyance (Berdan and Anawalt 1997:113; Coe
and Diehl 1980b:54-59; Doering 2002:97; Navarrete 1978; Rust and Sharer 1988;
Scholes and Warren 1965:779). Grove (1968:182) contends that Formative period trade
nodes were located on constricted passes along routes that were positioned to monitor the
flow of goods. A cursory examination of the river network around El Marquesillo
demonstrates that its position was a natural hub or focal point for multiple routes that
connected a variety of localities, both nearby and distant.
Figure 3.9 illustrates that the tributaries of the San Juan create a broad network
linking numerous regional ecological regions. One of the two primary tributaries of the
San Juan is the Río La Lana whose headwaters begin at Cerro Mirador, Oaxaca (1536 m
asl). La Lana’s principal tributary is the Colorado River, which extends to the slopes of
Nudo de Zempoaltépetl, Oaxaca (3412 m asl), both of these sources are deep in the Sierra
de Juarez in Oaxaca. The second principal tributary to the San Juan is the Trinidad River,
which is fed by the Chisme and Puxmetacán rivers. These waters drain the northern slope
of Cerro Casa de Piedra (2348 m asl), which is less than 15 km north of the Tehuantepec
River. The Tehuantepec flows out of the eastern end of the Valley of Oaxaca and empties
into the Pacific Ocean at Salina Cruz.
To the northeast of El Marquesillo, Arroyo Zanja Grande and Arroyo Zanja Prieta
flowed past either side of Laguna de los Cerros. These paleochannels resulted from
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