After great suffering Hsiian Tsang reached Igu, the seat of a Turkish principality, and pursued his way along the southern foot of the T'ian-shan, which he crossed by a glacier pass (vividly described) in the longitude of Lake Issyk-kul.
From Issyk-kul there is a sharp rise of6000-9000ft.
This last is continued without a break past the western end of Issyk-kul, being directly prolonged by the Alexander Mountains, although parted from them by the gorge of Buam or Bom, through which the Issyk-kul probably once drained.
It forms the barrier between the Issyk-kul and Balkash lakes, the elevation of which is about 5000 ft.
Above the Issyk-kul and lifts its summits higher than 13,000 ft.