Eastern and Northern Tien-shan.—The system is known here locally as the Barkul Mountains and the Karlyk-tagh. Its middle parts are snow-clad, the snow lying down to 12,000 ft. on the north side, while the peaks reach altitudes of 13,000-14,700 ft., but the range is only crossed by passes in the east, at altitudes from 7,805-10,984 ft. Towards the east, the Karlyk-tagh radiates outwards, and decreases in altitude, though it rises again in the rocky Emir-tagh. From the Karlyk-tagh a stony desert slopes south to the Chol-tagh. The Chol-tagh marks the northern escarp ment, as the Kuruk-tagh, farther south, the southern escarpment, of the great Pe-shan swelling of the desert of Gobi. These two ranges are eastern prolongations, the former of the Khaidyk-tagh and the latter of the Kok-teke Mountains, which enclose on north and south respectively the Yulduz valley and the Lake of Bagh rash-kul. Thus the Kuruk-tagh are linked, by the Kok-teke, on to the Khalyk-tau of the Khan-tengri group. The Khaidyk-tau, which are crossed by the passes of Tash-againym (7,610 ft.) and Kotyl (9,900 ft.), are probably connected with the Trans-Ili Ala-tau, or its twin parallel range, the Kunghei Ala-tau, in the west. The Narat-tau appear to form a diagonal link between the Khaidyk-tau and the Khalyk-tau and are crossed by passes Sary tyur (10,80o ft.), Mukhurdai (11,80o ft.), Jambi (I1,415 ft.) and the Dundeh-keldeh (11,710 f t.) .
West of the Barkul range is the gap of Otunkoza by which the Hami and Barkul caravan roads cross into the valley of Dzun garia, and at Urumchi (87° 3o' E.), over 200 m. farther west, is a similar gap which facilitates communication between Turfan and Dzungaria. Between these gaps stretches the snow-clad range of the Bogdo-ola, average altitude 13,00o ft., and rising to 17,000-18,000 ft. in the double peak of Turpanat-tagh. On the north side of this range the snow-line runs at an altitude of 9,500 ft. At the foot lies the broad, deep valley of Dzungaria (2,5oo 1,000 ft.). On the south the Bogdo-ola is flanked by the nearly parallel range of the Jargoz, a range which carries no perpetual snow. But its altitude does not exceed I0,00o ft., and its steep rocky slopes meet in a sharp, denticulated crest. West of the Urumchi gap, the Bogdo-ola is continued in the snow capped double range of the Iren-khabirga (11,50o ft.), which curve north west and finally, as the Talki Mountains, merge into the Boro khoro range. They culminate in the peak of Dos-megen-ora ( 20,000 ft.). The Boro-khoro Mountains (average elevation 11, 500 ft.) have all the characteristics of a border-ridge. The slopes are clothed with Coniferae between 6,000 and 9,00o ft., and the range separates the valley of Kulja (Ili) on the south from the depressions of Zairam-nor (6,820 ft.) and Ebi-nor (67o ft.). The passes in the Boro-khoro lie at lower altitudes than is usual in the Tien-shan ranges, namely at 7,000-7,415 ft.
On the north side of the valley of Borotala is the Dzungarian Ala-tau, the northernmost member of the Tien-shan. The two principal series of parallel ranges are the northern series (going from east to west) of the Baskan-tau, Sarkan-tau, Karazryk-tau, Bionyn-tau, and Koranyn-tau, at an average elevation of ii,000 13,000 ft., and the southern series of the Urtak-saryk, Bejin-tau and Kok-su, at altitudes of 12,000-14,000 ft.
Western and Southern Tien-shan.-On the north side of the Issyk-kul are the parallel twin ranges of the Trans-Ili Ala-tau and Kunghei Ala-tau. The two chains are connected by the lofty trans verse ridge of Almaty. The Trans-Ili Ala-tau swings away to the north-west, and is continued in the echeloned ranges of Kandyk tau, Kulja-bashi, Khan-tau and the Chu-Ili Mountains of general altitudes between 4,000 ft. and 9,00o ft. These latter ranges sep arate the Muyunkum desert on the west from the Balkash deserts. The Trans-Ili itself culminates in Mt. Talgar at an altitude of 15,725 ft. The Kunghei Ala-tau rises 8,000 ft. above the Issyk-kul and lifts its summits higher than 13,000 ft. The passes across the twin ranges lie at 8,000-ii,000 ft. (Almaty pass) in the Trans-Ili Ala-tau and at 9,000-10,885 ft. (Kurmenty pass) in the Kunghei Ala-tau. On neither of these ranges are there any true glaciers.
The Alexander Mountains terminate over against the town of Aulie-ata (7i° 20' E.) at the relatively low altitude of 2,46o ft., though farther east they rise to 13,000-14,000 ft., and even reach ft. in Mt. Semenov. On the north their declivities are steep and rugged. They are crossed by passes at 6,550-11,825 ft.
Near the west end of the Alexander range, (71° E.) the Kara tau stretches north-west, between the Syr Darya and the Chu. It consists almost entirely of sedimentary rocks. Its average eleva tion is 5,000 ft., in places it reaches 7,000-8,000 ft. In the same north-westerly to south-easterly direction are the Ferghana Moun tains. The Ferghana Mountains, which are cleft by the Naryn river, have a mean altitude of io,000 ft., but attain elevations of 12,740 ft. (Suyuk) and are crossed by the Terek pass at 9,140 ft.