PAINTED DESERT

section of the high plateau in north-central Arizona, U.S. The Painted Desert extends from the Grand Canyon in a southeasterly direction along the north side of the Little Colorado River to Holbrook. It is approximately 150 miles (240 km) long and 1550 miles (2580 km) wide and covers an area of 7,500 square miles (19,400 square km). The name was first used in 1858 by a government explorer, Lieutenant Joseph C. Ives, to describe the area's brilliantly coloured shales, marls, and sandstones, which are banded with vivid red, yellow, blue, white, and lavender. At times the air glows with a pink mist or purple haze of desert dust. Elevations range from 4,500 to 6,500 feet (1,370 to 1,980 m). The rolling surface is broken by isolated buttes and is bounded on the north by vermilion cliffs, rising to broad, flat-topped mesas. Marks of volcanic activity are abundant and widely scattered. The region is barren and arid, with 59 inches (127229 mm) of annual precipitation and temperature extremes of -25 to 105 F (-31 to 41 C). Part of the eastern section is within the Petrified Forest National Park and contains the Black Forest, one of four remarkable areas of petrified trees of Mesozoic age, about 170,000,000 years old. Navajo and Hopi Indian reservations occupy a large part of the Painted Desert, and the Navajo tribes use the variegated, brightly coloured sands for their famous ceremonial sand paintings.