others through the narrow Nomin-mingin-gobi gateway between the Barkul Hills and the advanced spurs of the Altaï north-westwards to Zungaria. Here the Mongolians were easily enabled to skirt on the north the whole Tian-shan system by availing themselves of the numerous passes opening westwards to the Ili basin, north-westwards to Lake Balkhash, northwards to the Black Irtish and Lake Zaïsan. These depressions between Mongolia and Siberia have a mean altitude of probably not more than 3,300 feet, and the highest point on the route from Barkul north-west to the Black Irtish is only 2,545 feet. The existence of an oblique chain, supposed by Richthofen to run north-west from Barkul to the Tarbagatai Mountains, has not been confirmed by Potantin's explorations, though a small ridge runs from the extremity of the Tian-shan at Barkul in a north-westerly direction, again joining the main range west of the town. This is the outer rim of an ancient lake, of which nothing now remains except the small Barkul basin, to which this town owes its Tatar name. Beyond the Barkul heights nothing occurs in the north-west as far as the valley of the Black Irtish, except irregular masses representing the islands and peninsulas of the old sea flowing between the Altaï and Tian-shan highlands.
Katûn and Yulduz Highlands.
West of the Urumtsi defile and of the old Turfan inlet the main range rises above the snow-line, and takes the name of Katûn, or Katin. This section, one of the least known in the system, is probably one of the highest, and undoubtedly exceeds 16,000 feet. No mention is made by the Chinese writers of any pass over it, and all the caravan routes skirt it east and west, while the lakes on both sides of the chain seem to point at extensive snow-fields on the uplands. Regel recently found vast glaciers about the sources of the Kash, which flows from the Katûn highlands westwards to the Kunges and Ili. Here the Tian-shan system develops into several parallel ridges, while south of the Katûn runs another chain through whose gorges the torrents from the main range escape to the plains. West of one of these gorges, traversed by an affluent of Lake Bogla-nor (Bostan-nor, or Bagrach-kul), the Tian-shan forms four parallel snowy ridges, known, like the neighbouring lake, by several different names, and enclosing two vast basins over 7,000 feet high. These so-called "stars" (Great and Little Yulduz) are the beds of old lakes, which now form natural pasture-lands watered by streams flowing to Lake Bogla-nor. It was in one of these vast cirques that Tamerlane, on his expedition against Kashgaria, assembled five armies from five different points of the Tian-shan, and ordered them to exterminate all the inhabitants of the land between Lakes Zaïsan and Bogla-nor north and south. The imperial tent stood in the middle of the plain, and the "Destroyer of the Universe" ascended his golden throne glittering with gems, and round about were the less sumptuous, but still gorgeous tents of his emirs. All received rich presents, and the troops were inflamed with rapture. These grazing grounds are the "Promised Land" of the nomad pastors, who here find the richest pastures for their flocks, and the finest climate, free even in summer from flies and mosquitoes. Yet Prejvalsky found this
