Note 2 — Chapter XXI · GEOGRAPHICAL

In western Asia the elevated area with its flanking ranges is bordered on the north by the northern Paropamisus and further west by the Caucasus chain. The Paropamisus may perhaps be regarded as the most southerly of the many branches which belong to the system of Tian-shan.2 Geologists invite us to connect the Paropamisus with the Caucasus, and trace the links of the broken chain to the mountains of Krasnovodsk on the Caspian, whence a submarine ridge carries the line into the mountains of Caucasus, to be protracted far to the west, through the Crimea, and emerge from the waters of the Black Sea in the Balkans, Carpathians and Alps. In this manner we see described on the north of the Asiatic highlands, with their series of inner arcs, a further arc of immense span and wide curvature, which is represented on the east by the northern Paropamisus and by the Caucasus on the west. Both these ranges may best be viewed as independent of the inner series; but Paropamisus is closely adpressed to the inner arc of Persia, and Caucasus is joined at a single point to the series, namely by the Meschic linking chain. Lines of elevation, similar to that which we have traced from Paropamisus, may be discovered, although with less orographical distinction, proceeding westwards and struggling over towards Europe from the more northerly branches of Tian-shan; they are almost lost in the great depression of the Turanian lowlands, but they follow arcs of increasing width of span.