ARDENNES, a district covering some portion of the ancient forest of Ardenne, and extending over the greater part of the Bel gian province of Luxembourg, part of the grand duchy, and the French department of Ardennes. One derivation is from a word meaning "the forest," turned into Latin as Arduenna Silva, and derived from the Celtic word ardu (dark, obscure). Another derivation is from ar-Denn or ar-Tann, Breton for the, or among the, oaks, whence Ardenne would be forest of oaks. A. Carnoy, a recent worker, derives it from a Celtic form for high-land, Ardu-enna being from the Indo-European arduos = high. The Arduenna Silva was the most extensive forest of Gaul, and Caesar (Bello Gallico, lib.vi.cap.29) describes it as extending from the Rhine and the confines of the Treviri to the limits of the Nervii. At the division of the empire of Charlemagne between the three sons of Louis the Debonnaire, under the pact of Verdun in 843, the Ardenne forest had become the district pagus Ar duensis. It was part of Lothair's share, and charters of 843 specify certain towns as in this pagus. In the Loth century the dis trict had become a comitatus, subject to the powerful count of Verdun, who changed his style to that of count of Ardenne.
The geographical region of the Ardenne extends from France through Belgium to the Rhineland and the duchy of Luxembourg south and east of a line through Couvin, Rochefort, Marche, Dur bry, Spa and Eupen, and its southern frontier is the Semois valley. Its geological boundary is that of the lower Devonian. It forms a broad low arch gently inclined north and south, the denuded base of a mountain chain once as high as the Alps, and then worn down to a peneplain. It consists of schists, sand stones and quartz-phyllites, with hardly any calcareous rock. The rivers in the up lifted peneplain cut gorges in the hard rocks, e.g., Les fonds de Quarreux on the Ambleve, but have wider valleys where the rocks are softer. The picturesquely wooded ravines are less truly characteristic than the great flat tops, naked wastes in many cases, which account for most of the area.
Decomposition of Cambrian schists has produced a waterproof clay soil in which sphagnum bogs grow, with their character istic accumulation of basal peat. The Hautes Fagnes on the Baraque Michel pla teau is the largest of these bogs. The peat was long used for fuel. On the more sili ceous lands, farms have been established but woods cover large areas and are among the most beautiful in Europe. They include the woods of St. Hubert, the woods round La Roche, and those of the Amerois, Herbeumont and Chiny on the Semois. In the grand duchy the forest has almost entirely disappeared, but owing to the compulsory law of replanting in Belgium this fate does not seem likely to attend the Belgian Ardennes. There is still an immense quantity of wild game to be found in the Ardennes, including red and roe deer, wild boar, etc. Shooting is preserved either by the few great landed proprietors left in the country, or by the com munes, who let the rights to individuals.