Bibliografía: páginas 181-193

The Tabasco lowlands form Mexico's largest alluvial coastal plain. Bordering the southernmost part of the Gulf of Mexico, these lowlands are hot and wet. They afford a laboratory in which to examine physical processes and living conditions within a humid tropical coastal environment. Geologically, the lowlands are composed of two distinct surfaces: (1) the Recent alluvial plain, made up of river deltas, flood plains, and beach deposits; and (2), farther inland, the Pleistocene alluvial surface of highly weathered stream-deposited sediments. The morphology of the Recent alluvial plain is a product of Mexico's two most voluminous rivers, the Grijalva-Mezcalapa and the Usumacinta. Several tropical vegetation formations, each with its particular faunal assemblage, once covered the Tabasco lowlands. Before its alteration by man a dense rain forest was the most extensive formation, followed in size by freshwater marsh in interlevee depressions. Despite a seemingly unfavorable environment, the Tabasco deltaic plain was well populated in pre-Columbian times, as evidenced by archeology and early Spanish accounts. After 400 years of demographic and economic decline, the lowlands have only recently regained population densities and economic importance comparable to those before the Conquest. (Author) Inglés