Thus the Kuruktagh are linked, by the Kok-teke, on to the Khalyk-tau of the Khantengri group. The Khaidyk-tau, which are crossed by the passes of Tash-againyn (7610 ft.) and Kotyl (9900 ft.), are not improbably connected orographically with the Trans-Ili Ala-tau, or its twin parallel range, the Kunghei Ala-tau, in the west, in that they are an eastern prolongation of the latter.
The 1st hill is distinguished by the Seraglio, St Sophia and the Hippodrome; the 2nd by the column of Constantine and the mosque Nuri-Osmanieh; the 3rd by the war office, the Seraskereate Tower and the mosque of Sultan Suleiman; the 4th by the mosque of Sultan Mahommed II., the Conqueror; the 5th by the mosque of Sultan Selim; the 6th by Tekfour Serai and the quarter of Egri Kapu; the 7th by Avret Tash and the quarter of Psamatia.
The landward wall started from a point near the present Stamboul custom-house, and reached the ridge of the 2nd hill, a little to the east of the point marked by Chemberli Tash (the column of Constantine).
Another hollow column, the pedestal of which is now known as Avret Tash, adorned the forum of Arcadius.
The principal passes are those followed by the old roads: - (1) from Sebasteia to Tephrike and the upper valley of the western Euphrates; (2) from Sebasteia to Melitene, by way of the pass of Delikli Tash and the basin of the Tokhma Su; (3) from Caesarea to Arabissus, by the Kuru Chai and the valley of Cocysus (Geuksun).