CAUCASUS MOUNTAINS. A mountain range on the Caucasian Isthmus, forming part of the botmdary between Europe and Asia. It extends in a west-northwest direction from the peninsula of Apsheron, in the Caspian Sea, to the peninsula of Taman, between the Black Sea and the Sea of Azov, being separated here from the mountains of the Crimea by the narrow Strait of Kerteh. The range is about 750 miles in length and from 60 to 125 miles in width. The narrowest section is almost in the middle of the isthmus, where the basin of the Terek River occupies it depression that leads into the Dariel Pass. While formed by several chains running parallel, or diverging and again uniting in mountain knots, the range is remarkable for its geographical and geological unity. West of the Dariel Pass there is an almost unbroken line of mountains exceeding the Alps in eleva tion, which forms a veritable barrier between the regions to the north and south. Eastward the Caucasus is lower. more broken, and is cut by numerous transversal valleys. The south ern slopes of the mountains are generally much sharper than the northern, which fall by grad ual stages to the level of the Terek and Kuban valleys. The range includes many massive peaks
of great altitude. Elbruz (18,470 feet), Kosh tantau ( 16.9001. Dikhtau (17,0(1(1) , Kasbek (16.5116), and other peaks overtop Mont Blanc. Elbruz and Ka slick are probably of volcanic origin. The loftier mountains carry fields of snow and ice, but the glaciers are not so extensive as in the Alps. where they have greater breadth and a lower snow-line. Most of the central ranges are composed of granite and crystalline schists. On the northern slopes Jurassic and Creta (TOW: sedi ments predominate, and are continued into the Caucasian steppes. where they dip below the Tertiary and Quaternary formations. The Ku ban and Rion rivers drain the western Cauca sits into the Black Sea, while the eastern region is drained by the Terek and Kur into the Cas pian. There are but few practicable routes across the range, the most important being from Vladikavkaz. on the northern side. through the Dariel Pass to Tiflis, which is used as a com mercial and military highway.