Quarried basalt was transported by raft through a network of rivers, to sites in the Olmec heartland for use in creating monuments, including colossal heads.

San Martín Tuxtla is the only recently active volcano in the belt, erupting in 1664 and again in May 1793.

The upper flanks of the San Martin Tuxtla and Santa Marta volcanoes are covered with the Neotropical Sierra de los Tuxtlas tropical rainforest ecoregion, of the tropical and subtropical moist broadleaf forests biome.

The Volcan San Martin rainfrog, Craugastor vulcani, is an endangered frog endemic to rain and cloud forests of Sierra de los Tuxtlas.

[3][4] The area is also home to an endemic species of giant scarab beetle, Dynastes moroni, described in 2005.