The westerly chain of the Giaour Dagh, indeed, was readily defensible. Except for a few local tracks available only in the summer, there are but few passes over its unbroken mass, and these are well defined. This splendid range of mountains, better known as Mount Amanus, forms a main branch of the Taurus system, from which it is divided only by the valley of the Pyramus. It separates Syria from Cilicia on the west, and touching the sea near Alexandretta follows the coast south-westward, until arrested by the broad valley of the Orontes. The average height of the chain is from four to six thousand feet, while some of its peaks reach almost to the snow-line.[16] Of the several passes that traverse it, that which leads transversely from Marash into Cilicia presents the easiest gradient, and is much used by caravans, though impassable by carts. The central pass above Bogche, however, is better known, being the direct line of communication between Cilicia and the East. Bogche itself is reached from Osmaniyeh on the eastern borders of the Cilician plain by a path which, while generally following the valley of the Bogche Su, traverses also some outlying ridges. The village is thus found picturesquely situated in an open and fertile spot among the hills. The long ascent thence continues up to one of the main sources of the same stream until the watershed is crossed, whence the descent is steep and rugged to the valley. The track then heads directly by Sakje Geuzi over the Qurt Dagh to Aintab, and so eastward to the crossing of the Euphrates. Though direct and not very difficult, this route is not yet made passable by carts, and perhaps for this reason the mail from Adana and the West takes the coast route, on mule pack, round to Alexandretta,[17] whence rises the main road to the interior. The Beilan Pass, as it is called, above Alexandretta, is by far the easiest, and the steep gradient on either side is so nicely engineered that it is hardly realised in passing where the watershed is crossed. Leading down directly to the fair seaport on the Mediterranean, this route for centuries has been a main channel of commerce between Europe and Asia; and until the railway connecting Aleppo with Beyrout diverted a large part of the traffic, caravans consisting of hundreds of laden camels in long procession could be seen daily, bringing out the merchandise of the East, and taking back the manufactured products of the West.