The geography, topography and ecology of Mexico

The geography of Mexico is very complicated.
It is reported that when Charles V, King of Spain, asked Cortes to describe New Spain, Cortes crumpled a piece of paper to represent the rugged landscape.
The land of Mexico is basically an up-side-down triangle, with its apex at the bottom, pressed between two oceans, the Gulf of Mexico and the Pacific.
The land is dominated by mountains and highlands which were created many millions of years ago by the forces of several tectonic plates which press against each other under the oceans.

The majority of topographic structures of Mexico run from north to south parallel to the two coasts and the tectonic plates, as shown in the adjoining map. Inland from the coastal plains (7,8), there are three rugged mountain chains: the Sierra Madre Oriental (5) in the east the Sierra Madre Occidental (3) in the west the Sierra Madre del Sur (12) in the southwest, which continues in the mountains of Central America and of Chiapas (15, 14). A high plateau (4 & 9) lies between the two mountain chains in the north. Its average altitude is approximately 6000 feet above sea level. The southern part (9) of the plateau is known as El Bajío, the "Lowland." The Transverse Volcanic Axis (10), is a unique topographic feature. It runs across the predominant north-south geographic axis, from one side of the country to the other. It is also called the Sierra Nevada.

The Transverse Volcanic Axis begins at the Pacific coast near Puerto Vallarte on the Bay of Banderas. This bay is just north of Corrientes Point where the Pacific coast turns southeast. The mountain chain runs in a diagonal line southeast to Veracruz. The majority of large cities of Mexico, including Veracruz, Puebla, Mexico City, Morelia and Guadalajara, are located along side these mountains. The Volcanic Axis contains the highest mountains, all volcanoes, in Mexico. These include: Pico de Orizaba, the highest mountain at 18,000 feet, near Veracruz. Popocatepetl and Ixtaccihuatl, between Puebla and Mexico City, Nevado de Toluca, west of Mexico City Paricutín in the State of Michoacán Nevado de Colima near the Pacific.

The three chains of mountains, the Sierra Madre Oriental, Sierra Madre Occidental and the Volcanic Axis or Sierra Nevada, have a great importance in shaping the ecology of Mexico. They stand as the frontier between the two great bio-geographical regions of the Americas created six million years ago when North and South America were joined when the land of Central America was pushed up from under the ocean by tectonic plates. The two bio-geographic regions are: the Neartic of North America and the Neotropical of South America At this frontier many plants and animals from the two regions came together, creating a grand biological mixture.

These mountain regions are called the "temperate land"because their climate is moderated by the altitude and the rains carried by the winds from the two oceans. They serve as the boundary between the "cold land" of the dry high plateau, where freezing temperatures may occur at night in the dry winters, and the "hot land"of the humid coastal plains.

The ecological systems of Mexico also follow this same boundary. The central high plateau is dominated by "xeric" dry brush and cactus. The mountains are covered with forests of pines or oaks. The coasts are tropical deciduous, semi-deciduous and evergreen jungles.

Reflections:
Land and climate mold everything living thing: plants, animals, humans.
They provide the structure and the energy for life. They are the foundation of the environment, the uterus in which life is created and grows.
For a man from New England, the land of Mexico is very strange.
The countryside of New England is gentle, moderate, with rolling hills covered in summer by soft, green trees.
Much of Mexico is rugged, changing rapidly from horizontal to vertical.
Much is dry, exposed land, open to the brilliant, hot sun. One feels exposed.
Mexico is a strong, intense land.