TARN, a river of southern France, 234 m. long, a tributary to the Garonne. It rises at 5,249 ft. on the Hercynian gneisses of Mt.
Lozere, flows westward and, having received the Tarnon, enters a gorge in the Jurassic limestones, which separates the Causse de Sauveterre from the Causse Mejan. It receives the Jonte (left) and passes between the Causse Noir, the Larzac plateau and the Causse de St. Affrique (left) and the Levezou range and the Plateau of Segala (right). At Millau it receives the Dourbie (left) and lower down the Dourdou (left) and from here to the cascade of Sabo, above Albi, the river crosses Permian and Silurian rocks. Having entered the plain, the river, has cut out a deep bed in the Tertiary strata, passes Gaillac, and, after receiving the Agout (left), it turns north-west, receiving the Tescou (right) at Mont auban, and the Aveyron (right). After passing Moissac it joins the Garonne on its right bank.
a department of south-western France, formed in 1808 of districts formerly belonging to Guienne and Gascony (Quercy, Lomagne, Armagnac, Rouergue, Agenais), with the addition of a small piece of Languedoc. From 1790 to 1808 its territory was divided between the departments of Lot, Haute-Garonne, Tarn, Aveyron, Gers and Lot-et-Garonne. It is bounded north by Lot, east by Aveyron, south by Tarn and Haute-Garonne, and west by Gers and Lot-et-Garonne. Area, 1,440 sq.m. Pop. (1931) 164,259. The department is the region focussing upon Montauban and includes the junction of the Aveyron and the Tarn and their union with the Garonne. These rivers separate hills of Pliocene strata, and in the extreme north east stands out the edge of the Plateau Central and the limestone Causse de Quercy (1,634 ft.). The climate is mild and agreeable;
the mean annual temperature being about 56° F. Rain falls seldom, but heavily, especially in spring, the annual rainfall being 28 or 3o in.
The wide alluvial valleys of the three large rivers are most productive. Cereals, especially wheat, maize and oats, occupy more than two-thirds of the arable land of the department. The vine is grown everywhere and large quantities of grapes are exported as table fruit. Potatoes are also grown. Plums and apricots are abundant. The breeding of horses, especially for cavalry purposes, is actively carried on; and the rearing of horned cattle, both for draught and for fattening, is also important. Sheep, pigs, poultry, and silk-worms are also sources of profit. There are metal-foundries, various kinds of silk-mills, and manu factories of straw-hats, wool, paper and brooms. The principal ex ports are fruit, wine, flour, truffles from the Rouergue, and early vegetables. The canal of the Garonne traverses the department for 48 m. and the Garonne and the Tarn furnish 82 m. of navig able waterway. The department is served by the Orleans and the Southern railways. The department forms the diocese of Mon tauban under the archbishop of Toulouse, and belongs to the academie (educational division) of Toulouse, where is its court, of appeal, and to the district of the XVII. corps d'armee (Tou louse). It has two arrondissements (Montauban, the capital, and Castelsarrasin), 24 cantons and 195 communes.