Similar rocks occur also in Chiapas, Oaxaca, Guerrero and elsewhere; but owing to the absence of any early fossiliferous deposits, the age of these rocks is very uncertain.
The tierras calientes (hot lands) of Mexico include the two coastal zones, the Isthmus of Tehuantepec, the states of Tabasco, Campeche, and part of Chiapas, the peninsula of Yucatan and a part of eastern Oaxaca.
The tierra templada, or sub-tropical zone, rises to an elevation of 5577 ft., and comprises " the greater portions of Coahuila, Nuevo Leon, San Luis Potosi, nearly half of Tamaulipas, a small part of Vera Cruz, nearly the whole of Chiapas, nearly all of Oaxaca, a large portion of Guerrero, Jalisco, Sinaloa and Sonora," together with small parts of the inland states of Puebla, Mexico, Morelos and Michoacan.
They inhabit the western Sierra Madre region from Sinaloa southward to Chiapas, the higher plateau states, which region was the centre of their empire when Cortes conquered them, and parts of Vera Cruz, Tabasco, Oaxaca, Morelos, Aguascalientes and San Luis Potosi.
Perhaps the most remarkable of the Mexican races are the Mayas, or MayaQuiche group, which inhabit the Yucatfin peninsula, Campeche and parts of Tabasco, Chiapas, and the neighbouring states of Central America (q.v.).