It has already been remarked, that these divisions are bounded on the east by the Belūt-tāgh mountains, which extend northward from the Hindū-kūsh to the Asfera mountains, are very lofty and precipitous, and bear snow on their summits the greater part of the year, some of them without intermission. They are probably very broken and abrupt, as no pass is known to cross them, except from Badakhshān. And it is remarkable that, in consequence of the height and abruptness of the mountains which enclose the country that has been denominated Uzbek Tūrkestān on the east, there appear in all ages to have been only two passes across them for caravans and armies, both of which are gained by following the course of the two great rivers, the Amu and the Sirr, to which the country appears to owe many of its most obvious features. One of these grand passes leads through Badakhshān, and is the route taken by the caravan of Kābul, and frequently by that of Samarkand and Bokhāra, on its road to Khutan and Kāshghar. This was the road followed by Marco Polo, in the thirteenth century, and more recently by De Goes, the last European who is known to have crossed these mountains. The second pass, which ascends by the sources of the Sirr, lies in the hills that separate Ferghāna from Kāshghar, to the eastward of Ush. This is the road by which the ambassadors of Shahrokh returned from China. Some inroads of Taimūr’s generals, by this pass, are recorded; and the caravan of Kāshghar seems to have taken this road in going between that city and Samar­kand in the time of Bābur’s father, as it does at the present day. The route pursued by the caravan of Tāshkend, on its way to Kāshghar and China, is not quite clear; but, in some instances, it seems to have gone up the right bank of the Sirr; and after passing the Julgeh Ahengerān, or Blacksmiths’ Dale, to have crossed the range of hills that encloses Ferghāna on the west, near Akhsi; to have proceeded on thence to Uzkend, and from that place by the same pass as the caravan of Samarkand. There is, however, reason to imagine that the caravan of Tāsh­kend frequently kept a more northerly course, skirting the Ala-tāgh hills that enclose Ferghāna on the north and east; and that after rounding them, and passing near Almāligh, it proceeded straight to Kāshghar. These are the only routes by which Eastern Turkestān appears to have been reached from the west; and an attention to this fact will explain several difficulties in the earlier historians and travellers. If the supposed route to the north of the Ala-tāgh hills was really one of those followed by the caravan of Tāshkend, it will perhaps explain a difficulty stated by Major Rennell, in his Memoir of a Map of Hindo­stān. After mentioning that Kāshghar was twenty-five days’ journey from Samarkand, he observes that one account differs so much from the rest that he will draw no conclusion from it. It is one that makes twenty-seven journeys from Tāshkend to Kāshghar, ‘although Tāshkend is supposed to be five journeys nearer to it than Samarkand is.’ If the Tāshkend route led round the hills to the north of Ferghāna, whence the traveller had to return southward towards Kāshghar, the itinerary in question will not be so inconsistent with the others as it might at first seem to be.