Blue Mountains. I. The central mountain range of the island of Jamaica. It extends E. and W. through the centre of the island, with offsets covering its eastern portion. The main ridges are from 6,000 to 8,000 ft. high, and are flanked by lower ranges, gradually sloping off into verdant savannahs. These mountains are remarkable for their steep declivities and sharp, narrow crests, which are sometimes only a few yards across. They cover the greater part of the island, the level portions being estimated at not more than 1/20 part of the whole. The valleys are deep longitudinal depressions, covered, as are also the sides of the mountains, with dense vegetation and stately forests. In the great earthquake of 1692 these mountains were terribly shattered and rent. II. A range in the S. E. part of New South Wales, extending through the counties of Cook. Roxburgh, and Westmoreland, nearly parallel with the coast, and forming the dividing ridge between the rivers of the coast and those of the interior. These mountains attain a considerable elevation, Mt. Beemarang, believed to be the loftiest peak, having a height of 4,100 ft. The road which crosses them, built in 1813, is in places 3,400 ft. high.

The range consists of ferruginous sandstone.