a mountain range of Scotland, in the county of Perth, about 24 miles in length, and having an average breadth of 12 miles. They extend from within 2 miles of the Forth, near Stirling, in a N.E. direction, to the Firth of Tay. The highest point is Benclough, at the S.W. extremity, 2300 feet above the level of the sea. The geological formation is basalt and greenstone, probably covering Silurian formations; and iron and copper ores have been found. The greater part of the hills afford good pastureage for sheep.