ROCK FORMATIONS IN THE GRAPEVINE HILLS—Fantastic shapes have been created by erosive action in the Big Bend National Park. Here, the massive boulders form a frame for the mountains in the distance.
Evidence of the tremendous force of erosion is very pronounced throughout the Big Bend National Park. Here nature has carved a cross section out of the earth leaving the rocks of various geological eras etched in bold relief. The Big Bend country reveals to the novice a greater understanding of the geological evolution through which the earth has passed. Scientists, who have searched the arroyos, buttresses and canyons, have obtained vital information and substantiating facts which have contributed to the knowledge and advancement of the science of geology.
Climatic conditions throughout the Big Bend region are mild and arid. Here again, in this land of contrasts, it is possible to experience a variation of temperatures and weather conditions. During the hottest part of the summer the high altitudes of the Chisos Mountains remain moderate and cool, while the temperatures are much higher along the lower plains, the desert and river valleys. The annual rainfall is light, varying from 8 to 20 inches. Although there is some snow and freezing weather in the mountains during the winter months, extreme temperatures normally are of short duration. In other sections of the Park the temperatures rarely drop below freezing. Throughout the winter the temperatures are mild along the Rio Grande.
ARROYO—Arroyos dip below the plains in appalling vistas of sand and desert wasteland revealing the continuous processes of erosion. The foothills of the Chisos Mountains are in the distance.
Outstanding in natural phenomena the scenic features of Big Bend National Park comprise a variety of spectacular attractions. In addition to the canyons of the Rio Grande, numerous colorful arroyos dip below the plains in appalling vistas of sand, rock and scrub vegetation of the desert. Buttresses push their towering masses into the azure sky, revealing a graphic account of endless battles with the elements. The uncovered strata opens the book of geologic history. High in the Chisos Mountains, majestically reigning over the Basin, Casa Grande, an erosive remnant of rhyolite, rises 7,300 feet above sea level. This massive monolith is a conspicuous landmark, photogenic in its moods of shifting lights and shadows. Climaxing the mountain scenery are the outstanding vistas that unfold from the South Rim of the Chisos Mountains. From this lofty plateau, more than 7,000 feet above sea level and a mile above the sprawling valley of the Rio Grande, the extensive awe-inspiring view reaches far into Old Mexico. To the east, blue and purple in the distance, ranges of the Sierra del Carmen and Sierra Fronterisa pose in their grandeur. More than a hundred miles to the south the distant Sierra Madres form the horizon line in Mexico and the Mesa de Anguila forms a sharp outline to the west. Dropping sheer from the South Rim, precipitous cliffs slope into the Lower Chisos, more than 1,000 feet below the rim.
TULE MOUNTAIN—Erosion has carved innumerable spires and buttresses out of Big Bend’s igneous rock.
WEST FACE OF THE SOUTH RIM—Dynamic and spectacular, the view from the South Rim of the Chisos Mountains reaches across the Rio Grande and far into Old Mexico.