All this would be more interesting if we could trace the route more closely which was followed to the Oxus. We know, however, that for previous centuries Balkh had been the capital city, the great trade emporium of all that region. There is therefore no difficulty in accepting Balkh as the Greek Baktria. Between Balkh and the Oxus the plains are strewn with ruins, some of them of vast extent, whilst other evidences of former townships are to be found about Khulm and Tashkurghan farther to the east, and on the direct route from Andarab to the Oxus. Bessos had retreated to Sogdiana of which Marakanda was capital, and the straight road to Marakanda (Samarkand) crosses the Oxus at Kilif. The description of the river Oxus at that point tallies fairly well with Arrian's account of it. It is deep and rapid, and the hill fortress of Kilif on the right bank, and of Dev Kala and other isolated rocky hills on the left, hedges in the river to a channel which cannot have changed through long ages. Elsewhere the Oxus is peculiarly liable to shift its channel, and has done so from time to time, forming new islands, taking fresh curves, and actually changing its destination from the Caspian to the Aral Sea; but at Kilif it must have ever been deep and rapid, covering a breadth of about three-quarters of a mile. Across the breadth nowadays is about as peculiar a ferry as was ever devised. Long, shallow, flat-bottomed boats, square as to bow and stern, are towed from side to side of the river by swimming horses. This would not be a matter of so much surprise if the horses employed for the purpose were powerful animals from fourteen to fifteen hands in height, but the remarkable feature about the Kilif stud is the diminutive and ragged crew of underfed ponies which it produces. And yet two, or even one, of these inefficient-looking little animals will tow across a barge of twenty feet or so in length, crowded with weighty bales of Bokhara merchandise, and filled as to interstices with its owners and their servants. The ponies are attached to outriggers with a strap from a surcingle or belly-band buckled to their backs, thus supporting their weight in the water at the same time that it takes the haulage. With their heads just above stream, snorting and blowing, they swim with measured strokes and tow the boat (advancing diagonally in crab-like fashion to meet the current) straight across the river. The inadequacy of the means to the end is the first thing which strikes the beholder, but he is, however, rapidly convinced of the extraordinary hauling capacity of a swimming horse when properly trained. Alexander crossed on rafts supported on skins stuffed with straw, and it took him five days to cross his force in this primitive fashion.