YDS READING PASSAGES / TEST 2 61. Soru

-21. GRAND CANYON

Nature's greatest example of sculpture, the Grand Canyon in northern Arizona is the most spectacular canyon in the world. It is a 446-kilometre gorge cut through high plateaus by the Colorado River. It is noted for its fantastic shapes and colours. Within the walls of the canyon stand imposing peaks, canyons and ravines. In general, the colour of the canyon is red, but each layer or group of layers has a distinctive hue — buff and gray, delicate green and pink, and, in its depths, brown, slate-gray and violet. The canyon 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. Grand Canyon National Park, which has 493,076 hectares, was established in 1919. Its area was greatly enlarged in 1975 by the addition of adjoining lands so that it now extends from Lake Powell to Lake Mead. The north and south rims of the canyon are connected by a paved road and by a trans-canyon trail. Scenic drives and trails lead to all important features. Mule-pack trips and river rafting are popular ways of viewing and experiencing the beauty of the vast canyon. The gorge has many rapids. Many cliff-dweller ruins indicate prehistoric occupation. There are several Indian tribes living on nearby reservations. No other place on the Earth compares with the mile-deep Grand Canyon for its record of geological events. Some of the canyon's rocks date back about 4 billion years. The river's speed and such "cutting tools" as sand, gravel and mud account for its incredible cutting capacity. The canyon has many varieties of wildlife. Willow trees and cottonwoods grow at the bottom of the canyon where there is plenty of water. There are magnificent forests on the north rim of the canyon where the soil is moist and deep. There are also drought-resistant plants, including numerous species of cactus. The first sighting of the Grand Canyon by Europeans is credited to the Coronado expedition of 1540. In 1869 John Wesley Powell organised the first party to go through the canyon. His account remains a classic of American travel.

By the 1870s extensive reports on the area were being published. It is clear that in the opinion of the author, the Grand Canyon ........ .