Middle America Landforms Online version Review map for the test by Julie Brown 1 Sonoran Desert 2 Sierra Madre Occidental 3 Sierra Madre Oriental 4 Plateau of Mexico 5 Sierra Madre del Sur 6 Yucatan Peninsula 7 Isthmus of Tehuantepec 8 Isthmus of Panama 9 Greater Antilles 10 Lesser Antilles 11 West Indies 12 Hispaniola 13 Baja California Peninsula