A third line of great importance is the junction line between the Transcaucasian railway - which runs from Batum and Poti to Baku, via Tiflis, with a branch line to Kars - and the railway system of Russia proper.
It is connected by rail with the south Russian railway system at Beslan, the junction for Vladikavkaz (400 m.), via Derbent and Petrovsk, with Batum (560 m.) and Poti (536 m.) on the Black Sea via Tiflis.
It is in this valley that the principal towns (except Vladikavkaz at the north foot of the Caucasus) of Caucasia are situated, namely, Baku (179,133 inhabitants in 1900), Tiflis (160,645 in 1897), Kutais (32,492), and the two Black Sea ports of Batum (28,512) and Poti (7666).
The highest mean temperatures for the whole year are those of Lenkoran (60.3°) and of Sukhum-kaleh and Poti (about 58°), and the lowest at Ardahan (5840 ft.), in the province of Kars, namely, 37.9°, and at Gudaur (7245 ft.), a few miles south of Kasbek, namely, 38.6°.
The exports through the Black Sea ports of Batum, Poti and Novo-rossiysk average in value a little over £ro,000,000 annually, though showing a tendency to increase slightly.