The Tas Kistabit mountains come next to the western Kolimski, the Cherski mountains are a longer range parallel to the whole curve of the Verkhoyansk-Kolyma line and stretching from the east of the Yana river to the west of the Omolon river. Within this again is a smaller range. The Cherski mountains are the newly discovered ranges named after a Russian explorer who died in this region in 1892, the river Indigirka traverses it by a winding gorge often less than a mile wide and the tributaries of this river also make gorges in this range, in which an altitude of about 3,3o0 m. (10,727 ft.) was observed. These high mountains are apparently almost without glaciers because of the aridity of the region. A geological traverse going northward between the Kolima and the Indigirka shows an east-west axis of igneous material alternating with Permian and Triassic rocks.
East of the mouth of the Omolon river a great axis of crys talline rock, flanked on both sides by Permian runs parallel to the coast as far as Cape Dezhnev (East Cape). The Kolimski mountains curving from the southwards come north-eastwards as the Anadir mountains and end in Cape Chukotski. This latter high line is flanked on the south-east by the Penzhina and Anadir valleys forming an almost continuous low line from the sea of Okhotsk across the base of the Kamchatka peninsula to the Gulf of Anadir north of the Bering Sea. The Kamchatka penin sula is described at some length in a special article (q.v.). North ward from Cape Lopatka along the east coast as far north as the curve of the Aleutian islands is a belt of volcanoes, part of the "girdle of fire" of the Pacific. The central longitudinal range of the peninsula is continued north-eastward, south of the Anadir valley to Cape Navarin. There thus seem to be three great struc tural lines abutting upon the neighbourhood of the Bering Strait and the north coast of the Bering Sea.
The main curve of the Stanovoi (Jurgur) mountains, sup posedly fold mountains, continues westward on the south and ap parently approaches the Yablonoi mountains, really the eastern edge of the Malkan horst, at an angle. To the west-north-west lies the Vitim plateau. To the south-east is found a type of topography analogous to that of Kamchatka and extreme north east Asia. There are successive ranges more or less parallel to the coast, imbricating to some extent and separated by lines of lowland fairly parallel with their axes. The Liao-ho, Sungari and lower Amur valleys form a continuous lowland from the Gulf of Pechihli to the strait between the mainland and Sakhalin. The Ussuri and lower Amur valleys form a low line from Vladi vostok northwards with the high range of the Sikhota Alin on its eastern flank. The se4:of Japan and the Gulf of Tartary, nar row waters separating Sakhalin from the mainland, form still another low line with the Sikhota Alin on the west and the high axis of Sakhalin, Hokkaido, etc., on the east. As in the case of
Kamchatka so also here the high axis is met on the east at a con siderable angle by the Kurile islands of volcanic type and south of this junction, that is in Japan, the high axis is volcanic, just as east Kamchatka is volcanic south of its junction with the Aleu tians. The great river of this eastern region is the Amur, which has a very large tributary, the Sungari, on the south; the Amur's course is governed mainly by the mountain lines of the region and its length is about 1,700 miles.
Having now, with the aid of references to other articles, briefly sketched some main features of the regions of Arctic drainage, the circum-Arctic platform and the Pacific mountains, we may turn to regions which drain elsewhere and which illustrate, though only slightly, some influences of the mountain building forces working in central Europe on blocks of ancient rock which have resisted folding and have remained almost horizontal. These regions are those which drain to the enclosed seas, the Black Sea, Caspian Sea, Aral Sea and Lake Balkhash, or looked at struc turally they reveal on the west a succession of very slight un dulations, anticlines and synclines, of small relief, with axes north west to south-east from the vicinity of the Carpathians to the borders of the Arctic region, and on the east the subdued features due mainly to the great virgations of the Tian Shan range.
Considering the matter first structurally we have from the Sea of Azov west-north-westward to beyond Kiev an anticlinal zone in which appear granites and gneisses, some of which are thought to be Archaean. The Dnieper from Kiev to Dnepropetrovsk (Ekaterinoslav) follows the northern border of this zone of hard rock through which the river cuts its way below the latter town.
Next follows a syncline in which early Tertiary deposits are most widespread, whereas farther south they only capped parts of the old rocks. The syncline is named after the river Donetz which follows its axis. Towards the Sea of Azov Palaeozoic rocks are brought to the surface and the land stands somewhat higher. In this region is the Donetz coalfield, the coal belonging to upper Carboniferous strata as in western Europe. The next zone is the central anticline which is parallel with the two structural zones described and which is thought to die away towards the Caspian. The axis of this anticline is marked to some extent by the Don river where it flows south-eastward below Pavlovsk while, much further north-west, the course of the southern Dwina is clearly related to it. Along it in the Don region the Cretaceous deposits, capped interfluvially by early Tertiary here and there, form the most important outcrops but on the north-west there is a great area of Devonian (v. inf.).