ARDENNES, department, northern frontier, France, com posed of the south-west side of the Ardennes towards the Paris basin, and of parts of the Meuse valley. Area 2,o28sq.m. ; pop. After a long course nearly south to north between edges of secondary rocks, the Meuse turns west as it approaches the Ardennes. These are remnants of ancient mountains, planed down, and then slowly tilted up from the south-east, allowing the river time to cut its way down while the uplift went on. It thus happens that just below Mezieres-Charleville the river enters a deep trench between moorland hills, and some of its entrenched meanders have given sites for isolated little towns like Revin. Mezieres also is on the peninsula of a meander. Northwards towards Givet the country opens out again and that old fortress town is an outpost of France, which owns the Meuse trench but not the flanking highland, standing on limestone rock that gives the district a much drier character than has the Ardennes. The Meuse is small in volume for its length and has lost several tributaries, the now almost streamless valleys of which have been used for canals e.g., that in this department between Meuse and Aisne.
In the south-west lowlands, with a fairly mild climate and often less than 800mm. of rain, general agriculture goes on, but among the higher lands (up to I,64oft.) the winter is cold and-the rain fall may exceed I,000mm. Here there are riverside pastures, but the people depend partly on quarries of slates (Fumay) and building stone and also work in iron. There is also naturally a woollen industry centring at Sedan, and Mezieres-Charleville is important as a railway junction. Mezieres, Rethel and the tiny Vouziers give their names to arrondissements. The department is in Reims ecclesiastical province, Lille educational province (academie), Nancy appeal-court area and 2nd army corps prov ince. The department was entirely occupied by the invaders 1914-18, but the defenders had just reached Sedafi and Mezieres at the end of the war. (For an account of the battles waged here in the World War see FRONTIER, BATTLES OF THE.)