JU'RA, Pr. pron. zhv'T.V. A range of moun tains on the western frontier of Switzerland. Beginning in Southeastern France on the north bank of the Rhone at Saint-Cienix, it extends northward, forming the west bank of the river till it reaches the Swiss frontier near Geneva. From that point it follows the boundary line in a long curve toward the northeast, finally passing wholly into Switzerland, and terminating en the south hank of the Rhine west of its confluence with the Aar (Map: Switzerland. A 2). The range thus defined is the .Tura proper. lint many geographers eontinue the name north of the Rhine and south of the Rhine. regarding these rivers as simply making two breaks in au other wise continuous chain. South of the Rhone the chain is known as the Jura Alps, and merges with the Alps of Dauphine., and other branches of the Western Alps. North of the Rhine an irregular chain extends east of the Schwarzwald throurdi Wiirttemberg and Bavaria as far as the Main River. This chain, called the German, m. Swa lan and Franconian. Jura. is similar to the Jura proper in the character of its rock formations, but different in its structure, being formed en tirely by faulting.
The Jura Mountains proper consist of a series of parallel folds in the strata, forming together a plateau nearly 200 miles long and DI to 35 mile- aide. These ridges have in many places suffered trans‘erse fractures, which in the torn QI steep gorges, known as 'closes,' ;old great 1,) In the picturesque character of the landscape.
The general height of the range is :MOO to 5000 feet. It is highest near the southern end, \lest of Lake (aie•a, where tile Cride de la Neige has an altitude of 5(153 feet. Other prominent summits are the Rivulet. 5643 feet ; the 1)51e, 5507 foot : and Mont Tendre, 5511! feel. The east ern slope falls abruptly toward the laeustrine basin fOrmIng tile v1:1 if( If Switzerland, and oven pied by the lakes of oemva, Neuchatel. Monne. and Aloral : westward and northward the slope is more gradual toward the Smlne Valley.
The Jura Mountains consist entirely of sedi mentary strata vomposcal of fossiliferous stone and lime-lone of Mesozoic age. This of rucks has given the name Jurassie system to one of the main divisions of the geologieal scale. (Uncial boulders are scattered over the slopes of the tura in countless numbers.
The climate of the Jura is relatively severe, and large masses of snow remain mr the '4111111161S (luring a great part of the tsar. The slopes are largely covered with pine forests, and agriculture is chiefly confined to the valley bottoms. The principal mineral moducts of the mountains are lithographic stones, gypsum. and salt.