It is also very probable that the Tannu-ola Mountains north-east of Ubsa-nor„ and the Khangai Mountains between Ulyasutai and the upper Orkhon, both running W.N.W.
On this vast upper terrace even the bottoms of the river valleys are at altitudes of 4200 to 5500 ft., with one single exception - the narrow gorge of the Khua (Khi)-khem, or upper Yenisei; while the highest pass across the Tannu-ola Mountains is 7090 ft., though the others are much lower.
In the Khangai, the Tannu-ola, and on the slopes of the border-ridges.
Are covered with forests, the Tannu-ola and the Khangai Mountains have woods on their northern faces only, and the Ektagh Altai is quite devoid of woods, even on its northern slope.
Coal is known to exist to the southeast of Kobdo, in the Tannu-ola, and in the basin of the Yenisei, but its age is unknown (fresh-water Jurassic ?).
Inscriptions in a kindred dialect were brought from El-Ola, in the north of the Hedjaz, by Professor Euting.
Above sea-level), Kirghiz-nor, Durga-nor and Kobdo-nor (3840 ft.), and traversed by various mountain ranges, of which the principal are the Tannu-ola, running roughly parallel with the Sayan mountains as far east as the Kosso-gol (boo - lob° E.
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.
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.
The passes across the twin 1 It may however eventually turn out that these ranges, together with the Mechin-ola, farther to the north-east and intimately connected with the Karlyk-tau, belong to the Altai system.