Ardennes, an extensive hill-country and forest, occupying the SE. corner of Belgium, between the Moselle and the Meuse, but extending also into France and Rhenish Prussia. It consists of a broken mass of hills, for the most part of no great elevation, which gradually slope towards the plains of Flanders. The average height of the hills is less than 1600 feet; but in the east, they attain an elevation of about 2100 feet. Large tracts of this region consist not of hills, but of gently undulating plateaus, in some districts densely covered with oak and beech forests, but for the most part heathy, marshy, and barren. The channel of the Meuse is in some places bound in by rugged and precipitous cliffs more than 600 feet high. The principal rocks of the Ardennes are clay-slate, graywacke, quartz rock, and various metamorphic rocks; besides which occur in various places extensive outcrops of crystalline limestone. The wealth of the region is its wood and its minerals. Enormous supplies of coal are found in the north, a very important element in Belgium's industrial wealth; iron, lead, antimony, copper, and manganese are also found. Multitudes of cattle and sheep are reared. The Arduenna Silva of the Romans extended over a still wider area. See Montagnac, Les Ardennes (2 vols. Par. 1875);
Lindley, Walks in the Ardennes (1887).—Shakespeare's Forest of Arden is a district in Warwickshire, extending from the Avon to near Birmingham.