(Ger. Leberberg, Fr. Jorat), a chain in the S.W. of Switzerland, extending from the canton of Schaffhausen S.S.W. to Savoy. The curve which it forms is about 200 miles long; its breadth being about 30 miles. The Jura chain strikes through Soleure, Berne, and Neuchâtel, parallel to the great range of the Bernese Oberland, and forms the frontier between the Canton de Vaud, and the French department of Jura. The N.W. portion of the range is low; further to the S.W. it is precipitous on the Swiss side; and on the French side it gradually retires in ridges, which successively become lower. Some of the highest points of the range are as follows:

| Peak | Height | |---------------|--------| | Mont Moleson | 6577 | | Reculet de Thoiry | 5627 | | Grand Colombier | 5567 | | Mont Tendre | 5521 | | Mont Chasseral | 5410 | | Mont Chasseron | 5400 |

The following are some of the passes:—Fort Ecluse, close under Mont Vouache; Col de Villeneuve, S. of Grand Colombier; Marchairu, S.W. of Mont Tendre; Echelle, S.W. of Mont d'Or; Verrières, near Pontarlier; Pierre Pertuis, an immense archway cut through the rock in the Valley of St Imier as early as the time of the Romans; and the Klaus Pass in Ballsthal, important as a military station in time of war. The chief roads by which the range is crossed are from Nyon into France, over St Cergue; from Orbe, Yverdon, and Neuchâtel, to Pontarlier—the latter of these being by the picturesque Motiers Travers; also from Neuchâtel to Morceau in France; from Biel to Porrentruy; two from Basle to the interior of Switzerland, viz., the Upper and Under Hanenstein; over Staufenegg, between Frickthal and Aarau; over Bötzberg between Basle and Zurich, an old road which existed in the time of the Romans.

Geologically the Jura chain is a limestone formation, varying between grey and yellow in colour. (For the Jurassic formation, see Mineralogical Science.) The strata are tilted up sometimes almost perpendicularly, and contain stalactite caverns usual in limestone districts. The more remarkable of these grottoes are in the valleys of Verrières, Travers, Orbe, and Frick. Beds of marl and clay are found alternating with the limestone. Marble, asphalt, and gypsums are also found; iron and coal never in such abundance as to form an important source of wealth. The iron mines have as yet been turned to account only by the French. The same remark applies to the rich salt springs of Salins, Montmorot, Courbasson, Tormoet, Grosen, and in the neighbourhood of Poligny, which occur in the chain. The fossils consist of the bones of large Saurians, Didelphis, crabs, shells, ammonites, zoophytes, coral, wood, &c. The trees which at present grow on the range are mainly pine and box. The former are found in large quantities near Poligny, and afford materials to the French for ships of war. The forests of ash, lime, beech, &c., also afford an abundant supply of wood for the iron-foundries and salt works of Arc, Salins, &c. During the rigour of winter the inhabitants occupy their time in cutting all sorts of fancy articles of wood, from which they derive considerable revenue. Wolves are numerous; and the brown bear, at one time so destructive to herds, is still found in the more secluded parts of the Western Jura.

The pastures are covered with the herds which supply the Gruyere cheese. The meadows are so well watered by nature and art that they yield three crops a-year; vineyards occur in the valleys. There are no glaciers, and snow lies only in the sheltered ravines. A remarkable phenomenon, occurring all along the Swiss side of the Jura, is the existence of large detached blocks of granite and gneiss, the chain itself consisting of limestone. The largest of these blocks is the Pierre-a-bot (toad-stone), upwards of 60 feet long. It is about 2 miles above Neuchâtel, and the nearest rock of the same kind is found at Great St Bernard. In the same way protogine blocks occur near Geneva, which must have come from Mont Blanc; while towards the N.W. extremity of the range others occur, which must have come from the direction of the Grimsel. It has been supposed, accordingly, that these masses were borne by huge glaciers along the Arve, the Rhone, and the Aare, across the plain of Switzerland, and thus deposited in the places in which they now stand.