MULL, an island of Scotland, county of Argyll, and the largest of the Inner Hebrides, is bounded W. by the Atlantic, N. by Loch Sunart, N.E, by the Sound of Mull, and S.E, by the Firth of Lorn. Its area comprises about 235,000 acres, of which only about 13,000 are arable. It is triangular in shape, its greatest length being about 24 mile, and its greatest breath about 30 miles. Lochs Na-Keal and Scridain form deep indentations on its western coast, and there are a large number of smaller inlets. The coast-line is rocky, and especially on the west there are numerous caverns and horizontal terraces of basalt. The prevailing rock is Old Red Sandstone, but the valleys are filled up with Miocene rocks, consisting chiefly of lava flows and ashes of great terrestrial volcanoes. There is an intrusion of granite towards the south, and also a narrow belt of limestone. The surface is for the most part rugged and mountainous, Ben More rising to the height of 3185 feet. Sheep and black cattle are kept, and barley, oats, and potatoes are grown. Herring fishing is prosecuted at Tobermory, where is one of the best and safest of the western harbours of Scotland. There are several ancient castles, the principal being those of Duart and Aros. The population of the island in 1881 was only 5229.