BLUE MOUNTAINS

range in eastern Jamaica, that extends for about 30 mi (50 km) from Stony Hill, 8 mi north of Kingston, eastward to the Caribbean Sea. The highest point in the range is Blue Mountain Peak (7,402 ft ). The Blue Mountains are thickly covered with tree ferns. The slopes facing the trade winds receive an average of 200 in. (5,000 mm) of rain annually, resulting in much topsoil erosion and a network of streams. Winter temperatures may fall to 45 F (7 C), while frost and even sleet have been experienced on Blue Mountain Peak. Coffee, formerly grown on large plantations, is cultivated in the valleys by peasants. section of the Great Dividing Range, New South Wales, Australia. The range comprises a well-dissected sandstone plateau that rises from an eastern escarpment (1,2001,800 feet [370550 m]) to 3,871 feet (1,180 m) in a western scarp at Bird Rock. Its slopes are generally precipitous. The first Europeans to cross the range were the explorers Gregory Blaxland, William C. Wentworth, and William Lawson in 1813. The range was used as a retreat for wealthy Sydney residents; it is now accessible by good roads and forms a popular tourist area with many scenic attractions, including Jenolan Caves and the Zig Zag (an abandoned railway providing a route over the mountains). Blue Mountains National Park, a 768-sq-mi (1,989-sq-km) nature reserve centred on the Grose River Valley, lies within the region. The mountains are named for their bluish colour, which apparently is caused by light rays diffusing through droplets of oil dispersed into the air by the many types of indigenous eucalyptus trees. The City of Blue Mountains is a confederation of more than 20 townships, formed in 1947. The principal centres are Katoomba, Leura, Mount Victoria, Blackheath, Springwood, Wentworth Falls, and Hazelbrook, all of which lie on both the rail line and Great Western Highway between Sydney (40 mi east) and Lithgow on the western slopes of the mountains. Urban growth has been rapid, as the area is a popular vacation centre. Pop. (1981) 55,877. range curving northeastward for 190 mi (310 km) from central Oregon to southeastern Washington, U.S. The range reaches a width of 68 mi and an average elevation of about 6,500 ft (2,000 m); it comprises an uplifted, warped, and dissected lava plateau, above which rise several higher mountain ridges, including Aldrich, Strawberry, and Elkhorn. The highest peak is Rock Creek Butte (9,105 ft), on the Elkhorn Ridge. The mountains are drained by tributaries of the Columbia River. At lower elevations, the basins or flats are cultivated, some with irrigation. The slopes are heavily forested with pine and Douglas fir. Stock grazing and outdoor recreation are the main activities in the region since the decline of mining. The mountains are within parts of the Umatilla, Whitman, and Malheur national forests and probably received their name from the dark-blue appearance of the pine trees.