Sierra Madre Oriental

Sierra Madre Oriental 

a mountain range in Mexico, along the eastern edge of the Meseta Central. The Sierra Madre Oriental is a system of parallel ridges about 800 km long. In the east the mountains drop sharply toward the coastal plain; in the west they rise above the inland sections of the highland only in places. The highest peak is Peña Nevada (4,054 m). The Sierra Madre Oriental is composed of Upper Mesozoic sedimentary rocks. The northern part is covered with xerophytic shrubs; in the southern part the windward eastern slopes are forested, with tropical rain forests growing on the lower slopes and conifers in the upper zone; the leeward western slopes are covered primarily with shrub thickets.