YONNE, a department of central France, is bounded N.E. by the department of Aube, E. by Cdte-d'Or, S. by the department of Nievre, W. by that of Loiret, and N.W. by Seiuc-et•Marue. It lies between 47° 20' and 48° 24' N. lat., 2° 55' and 4° 20' E. long. Its greatest length is 82 miles; the greatest breadth is 53 miles. The area is 2868 square miles; and the population in 1851 amounted to 381,133.
The surface is in many parts undulating ; the highest ground is toward the south-western corner, where the low hills which separate the basin of the Loire from that of the Seine cross the department. The country about Avallon is comprehended in the granitic district of Morvan ; the rest of the department is occupied by the oolitic formations, except the north-west of the department, which is occupied by the chalk formations. Iron-ore is obtained ; freestone, sandstone, and stone suitable for lithography are quarried; and gun-flints, and red and yellow ochre, are procured. A mine of lead and silver was formerly worked near Avallon.
The department belongs almost entirely to the basin of the Seine. Some parts along the western border are drained by the Loing and its affluents; the central and eastern parts are drained by the Yonne and its tributaries the Cure, the Serein, the Armangon, the Tholon, the Vrin, and the Vannes. The Loing and its feeder the Ouanue rise in the south-west part of the department, and have a north-western course into the adjacent department of LOIRET, in which their junction takes place. The other feeders of the Loiog have only their sources and the upper part of their course in this department. Thd Yonne rises in the department of Nievre, near Chateau-Chinon ; and flows north-north west into the department of Youne, where it passes Coulanges, Auxerre, Joigny (between these towns it receives the Serein and the Armangon, both on the right bank); and just below Joigny it receives the Thelon and Vrin, both on the left bank), St. Julien, Sens (near which it receives the Vannes on the right bank, and Villeneuve-la-Guiard. Below Ville neuve-la-Guiard it quits the department and enters Seine-et-Marne, through which it flows a short distance west-north-west to Montereau fault-Yonne, where it unites with the Seine. Its whole course is about 150 miles. The river is employed for floating timber from near its source: at Ctamdcy the timber is formed into trains or rafts, and floated down to Auxerre. At Auxerre the navigation commences, and extends for about 64 miles, the greater part of it in this department. The Cure rises in the department of Nievre, and flows north north-west into the department of Yonne, and by Vermanton into the river Yonne on the right : its whole course is above 50 miles. The Voisin, which
joins the Cure, and its feeder the Cousin, both rise in tho department of C6tesd'Or, and flow north-west. The Serein rises in the department of C6te-d'Or, and flows north-north-west into the department of Yonne, where its course bends more towards the west. The A rmancon rises in the department of C6te-d'Or, and flows north-north-west by Semur into the department of Yonne, through which it flows north-west by Nuits, Tonnerre, and Dannemoine ; then westward by St.-Florentin and Bri6non into the Yonne. Its whole course is about 02 miles. Both the Armancon and its feeders, including the Armance (which flows into it from the department of Aube), are used for floating timber, and vast quantities of firewood down to Paris.
The Canal de Bourgogne, which connects the Seine with the Rhone, commences in the Yonne, and passes up the valley of the Armancon, then up the valley of the Brenne, a feeder of the Armancon, and, crowing the hills which separate the basin of the Seine from that of the Rhone, follows the valley of the Ouche till it terminates in the &One at St-Jean-de-Loene. The summit-level is at Ponilly in the department of Cate-d'Or, so that all the part of the canal which is in this department (of Yonne), officially stated at 91,638 metres (about 57 miles), is on the side of the descent from the summit-level to the Yonne : this descent is of 311 metres (about 1020 feet). and is effected by 115 locks. This canal was projected by Henri IV., but was not commenced till 1775; and if finished (of which we have no certain information) has been completed only within a very few years. The department is traversed b7 the Canal de Bourgogne, which connects the navigation of the Seine with that of the Rhone, commencing in the Yonne at the month of the Armancon, and terminating in the Saone at St-Jean-de-Lassie [Cstaven'Oe]; and by the Nivernais Canal, which commences in the Loire at Decize, In the department of Nievre, passes up the valley of the Aron, is carried by s, tunnel under the mountain of Coloncelle, and descends from the summit-level to the Yonne at Auxerre, thus connecting the navigation of the Loire with that of the Seine. The department is traversed by 6 imperial, 19 departmental, and a great number of communal or parish roads; and also by the Paris-Lyon railway, which panes Sens, Jaiguy, and Tonnerre, and sends off a branch from Joigny to Auxerre.