And is probably continued even farther by the Artsa-bogdo, the Saikhat and other ranges as far as the northern loop of the Yellow river.
The southern chain bears the names of Karaadzirga and Burkhan-ola, and terminates in about 99 0; but the northern range, the principal names of which are Artsi-bogdo and Saikhat, extends probably most of the way to the great northward bend of the Hwang-ho or Yellow River round the desert of Ordos.
This is not, however, the absolutely lowest point in East Turkestan: that is found in the local depression of Turfan-Lukchun, south-east of Urumchi, between the Choltagh and the Bogdo-ola ranges of the Tian-shan.
And the Bogdo-ola and Karlyk ranges run up to 15,000 to 18,000 ft., while the passes (e.g.
2390 ft.) the principal constituent ranges are the Bogdo-ola, continued west and north-west in the Iren-khabirga, the Talki Mountains and the Boro-khoro, flanking in succession the great depression of Dzungaria on the south.
Between these two gaps stretches the snow-clad range of the Bogdo-ola, which runs at an average altitude of some 13,000 ft., and rises to an altitude of 17,000-18,000 ft.
On the south the Bogdo-ola is flanked by the nearly parallel range of the Jargoz, a range which, in contrast to most of the Tian-shan ranges, carries no perpetual snow.
West of the Urumchi gap, the Bogdo-ola is continued in the double range of the Iren-khabirga Mountains (11,500 ft.), which curve to the north-west and finally, under the name of the Talki Mountains, merge into the Boro-khoro range.
The Iren-khabirga, like the Bogdo-ola and the Terskei Ala-tau, are capped with perpetual snow.