The mountains of Crimea, like the Carpathians, are mountains of plication. They are composed of Jurassic, chalk, and miocene-layers. The large blocks of lime of the Jurassic, which rest on softer slates and clays, form the main ridge of the mountains. Besides craters, we find, in the limestone mountains of the Yaila, impassable furrows (German Karrenbildungen) and numerous hollows.
Very picturesque is the magnificent precipitous decline of the main range of the Yaila to the sea. Here the entire southern part of the range has sunk in great ravines and the resisting power of the eruptive rocks which appear here has created a coastal mountain landscape of great beauty. Protected by the mountain wall from northerly winds, a Mediterranean flora has been able to develop here at the southern foot of the range, while beautiful leafy forests partly cover the declines of the mountains.
On the peninsula of Kerch, which forms the eastern extreme of Crimea, a low steppe-like hill-country extends seemingly as a prolongation of the Yaila Range. The new tertiary clays are here laid in flat folds, which are more closely related to the Caucasus. Here, and on the quite similarly formed Taman peninsula, we find many small cone-shaped mud volcanoes which emit gases, smoke, and thinly flowing blue-gray mud from their miniature craters.
The magnificent lofty range of the Caucasus forms the boundary-post of the Ukraine on the east. Only the western part of the mountain system lies within Ukrainian territory. We shall, therefore, discuss it quite briefly.
The Caucasian Mountain system, which is 1100 km. in length, lies like a huge wall of rock between Europe and Asia. Most geographers consider the Caucasus as part of [[36]]the latter continent, which is correct in so far as these mountains show many characteristics of Asiatic mountain ranges. First of all they are hard to cross, much harder than the highest mountains of Europe, the Alps. Along a stretch of 700 km., the ridge of the Caucasus descends only twice to a level of 3000 m. On the other hand, the Caucasus is not wide—on the average only 150 km.—and at the point where the Grusinian army road crosses the range, barely 60 km. Then, the Caucasus, like many mountain ranges of Asia, stretches in a straight line from the peninsula of Taman to the peninsula of Apsheron, famous for its abundance of petroleum.
The Caucasus is a plication-formed mountain range composed of folded crystalline and sedimentary rock of varying ages. Along huge ravines, the entire southern part of the range has sunk down, so that the highest crystalline central zone of the range declines directly and very steeply toward the south. The highest Caucasus peaks are old extinct volcanoes, set over the basic mountains; the Elbrus (5630 m.), at the source of the Kuban and the Kasbek (5040 m.), at the source of the Terek. Proof that the subterranean powers are still active are the numerous tectonic earthquakes of Transcaucasia.
The main chain of the Caucasus possesses, besides the volcano peaks, many rocky granite peaks 4000–5000 m. in height, and, besides these, hundreds of lower peaks, all of which find their counterparts in the Alps. The present glaciation of the Caucasus is very considerable, while that of the glacial period was also very extensive and determined the present mountain forms of the Caucasus. Only the most beautiful ornament of the one-time glacial landscape is lacking in the Caucasus—the lakes, which are so abundant in the Alps.
All the larger Caucasus rivers rise as milky glacial brooks in the main range. Then, by way of deep cross-valleys, [[37]]they break thru the lower ranges, which face the main ridge in several rows, and are composed of sedimentary rock formations of jurassic, cretaceous, and old-tertiary age. Their crests and peaks become constantly lower and more rounded toward the north. Beautiful mountain pastures and thick virgin forests, full of animals that may be hunted, cover the mountains.
In the country at the foot of the Caucasus, a low hill-region is spread, which consists mainly of new-tertiary layers abounding in petroleum. At the Ponto-Caspian divide, the hill-district and plateau of Piatihorsk and Stavropol, which is composed of recent lime formations, projects from the Caucasus. From a height of 600 m. this structure declines slowly in flat hills toward the west, north and east to the Ponto-Caspian steppe-plain, in which lies the famous Manich Furrow. The Manich, or rather Calaus River rises like the Kuma in the Plateau of Stavropol and separates, in the Furrow, into two branches. The one flows thru extended Manich lakes toward the northeast into the Don River, and, incidentally, into the Sea of Azof; the other turns toward the south to the Kuma River and the Caspian Sea. But its waters reach this goal very rarely; the burning sun and the sandy soil of the Caspian steppe rob the little river of its small supply of water.