Grand Canyon


Immense gorge cut by the Colorado River into the high plateaus of northwestern Arizona, U.S., noted for its fantastic shapes and coloration.
The broad, intricately sculptured chasm of the Grand Canyon contains between its outer walls a multitude of imposing peaks, buttes, canyons, and ravines. It ranges in width from about 0.1 to 18 miles (0.2 to 29 km) and extends in a winding course from the mouth of the Paria River, near the northern boundary of Arizona, to Grand Wash Cliffs, near the Nevada line, a
distance of about 277 miles (446 km). The canyon includes many tributary side canyons and surrounding plateaus. The deepest and most impressively beautiful section, 56 miles (90 km) long, is within Grand Canyon National Park, which encompasses the river's length from Lake Powell to Lake Mead. In its general colour, the canyon is red, but each stratum or group of strata has a distinctive hue--buff and gray, delicate green and pink, and, in its depths, brown, slate-gray, and violet. At 8,200 feet (2,500 m) above sea level, the North Rim is 1,200 feet (350 m) higher than the South Rim.
The first sighting of the Grand Canyon by a European is credited to the Francisco Coronado expedition of 1540 and subsequent discovery to two Spanish priests, Francisco Garcés and Silvestre Vélez de Escalante, in 1776. In the early 1800s trappers examined it, and sundry government expeditions exploring and mapping the West began to record information about the canyon. By the 1870s, following the exploration of John Wesley Powell and others, extensive reports on the geography, geology, botany, and ethnology of the area were being published.
Grand Canyon National Park, now containing 1,904 square miles (4,931 square km), was created in 1919. Its area was greatly enlarged in 1975 by the addition of the former Grand Canyon National Monument and Marble Canyon National Monument and by portions of Glen Canyon National Recreation Area, as well as other adjoining lands. The North and