Basin

Big Bend National Park, the first national park in Texas, comprises more than 1,250 square miles (about the size of Rhode Island) in the Big Bend of the Rio Grande along more than 100 miles of the Texas-Chihuahua-Coahuila border southeast of El Paso in Brewster County. It has been described as a land of "killing heat and freezing cold; deadly drought and flash flood; arid lowland and moist mountain woodland; and a living river winding its way across the desert." The Rio Grande flows for 107 miles on the park's southern boundary, through Santa Elena, Mariscal, and Boquillas canyons, the deepest gorges on the river. In 1978 the United States Congress designated a 191-mile section of the Rio Grande a Wild and Scenic River, sixty-nine miles of which lie on the park boundary. Most Big Bend acreage is arid alluvial plains, the most representative example of the Chihuahuan Desert in North America. The Chisos Mountains, the southernmost range in the continental United States and completely enclosed in the park, rise over 7,800 feet above sea level. They support relict forests from the late Pleistocene era of ponderosa pine, Douglas fir, Arizona cypress, quaking aspen, and bigtooth maple. The popular Basin, a topographic depression in the Chisos range, offers visitors a cool respite from the desert heat and spectacular panoramic vistas. Annual precipitation in the arid to semiarid climate ranges from five inches in the desert to twenty inches in the mountains. The National Park Service considers Big Bend "one of the outstanding geological laboratories and classrooms of the world." Geological processes readily visible at the park are sedimentation, deformation, and volcanism. Recovered fossil forms of ancient plants and animals include a bivalve three feet wide and four feet long, the largest known pterosaur (a flying dinosaur), and the skull of a chamosaurus, a horned dinosaur, all of which help make Big Bend an invaluable resource for paleontological research and preservation.

Adapted from the official Handbook of Texas, a state encyclopedia developed by the Texas State Historical Association (TSHA). It is an authoritative source of trusted historical records.