Circuit was made to the north and west, across the Humboldt range, and by Hami, Urumchi, and Yarkand to Ladak again.
There is also an import and export trade to and from Urumchi and China, via Kulja and Ak-su.
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.
But here two natural gaps or gateways, those of Urumchi at 2790 ft.
Along the south foot of the Tian-shan, and in the high valleys which intervene between the constituent ranges of that system, there exist numerous flourishing oases, such as Uch-turfan, Ak-su, Kucha, Korla, Kara-shahr, Hami, Barkul, Turfan, Urumchi, Manas and Kulja.
Nevertheless certain of the oases are famous individually for one or more handicrafts: for instance, Khotan for its silks, white carpets and felt goods; Kashgar and Turfan for cottons, Kucha and Kara-shahr for leather and saddlery, Ak-su for felts and leather and metal goods, Yarkand for silks, carpets and felts, and Urumchi and Uch-Turfan for sulphur.
At the west end of the Barkul range is the gap of Otunkoza (2390 ft.), by which the Hami-Barkul caravan road crosses into the valley of Dzungaria, and at Urumchi (87°30' E.), over 200 m.
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.
After traversing the desert of Gobi from Sa-chou to Hami, the great northern route crossed over into the Dzungarian valley either by the Otun-koza depression or by the gap at Urumchi, or else it proceeded over the Muz-art pass on the east side of Khan-tengri or over the Bedel pass in the Kokshal-tau and so down into the valley of Kulja.