This railway, together with the driving roads over the Caucasus mountains via the Mamison pass (the Ossetic military road) and the Darial pass (the Georgian military road), and the route across the Black Sea to Poti or Batum are the chief means of communication between southern Russia and Transcaucasia.
These basins or ` longitudinal folds ' are enclosed on the south by the long high ridge of dark slates, which extends parallel to the crystalline [main] chain from the neighbourhood of Sukhum-Kale to the Krestovaya Gora [pass of Darial.] Behind this slate crest spreads a confused multitude of hills, Jurassic and Cretaceous in their formation..
These means of communication are the passes of Darial and Mamison.
- In this sub-section, which stretches from Kasbek and the Darial gorge eastwards to the Baba-dagh in 48° 25' E., a distance of 230 m., the Caucasus attains its greatest breadth.
The best known are the Krestovaya Gora (7805 ft.) on the Georgian military road, south of Darial; Kodor (93 00 ft.) and Satskheni, leading up from Telav in the upper valley of the Alazan; and Gudur (10,120 ft.) and Salavat (9280 ft.), carrying the Akhty military road from the valley of the Samur up past the Shah-dagh and the Bazar-dyusi to the valley of the Alazan.
That of Darial (the Terek) is fairly well known, but those of the Cherek and the Urukh, farther west, are stated to be still more magnificent.