GIBRALTAR, Bay of, or, as it is sometimes called, ALGECIRAS BAY, is bounded by the rock of Gibraltar on the one side, and the headland of Cabrera on the other. Its greatest length is about eight miles from N. to S., its greatest width about five miles from E. to W., and its circuit nearly forty miles. Its depth in the centre is about 110 fathoms. In spring tides the water rises in the bay about four feet. Algeciras, from whose name the bay is sometimes called, is a fortified Spanish town on the W. side of the bay, over against Gibraltar. Near it is the beautiful little island called Isla Verde, or Green Isle.