Above the general level of that plateau, connect the central Nan-shan with the next parallel ranges, namely, those of the eastern Nan-shan.
This border-range, which continues on to the 97th meridian, separates the Nan-shan range from the Pe-shan range.
Generally speaking, the Nan-shan highlands are a region raised 12,000 to 14,000 ft.
In the central Nan-shan it is only the north-eastern slopes that bear forests.
The Pe-shan swelling, with its flanking ranges of the Chol-tagh and Kuruk-tagh, which, by gradually approaching the Nan-shan section of the Kuen-lun in about 98° E., narrow the desert, are a good deal lower, namely 5000 to 9000 ft.
The southern half of the province, that portion south of the Yangtsze Kiang, forms part of the Nan-shan, or hilly belt of the south-eastern provinces, and produces, besides cotton, coal and iron ore, large quantities of green tea.
The Nan-shan mountains consist of short irregular chains, separated by broad plains, dotted with lakes, which differ but slightly in altitude from Tsaidam (8800-900o ft.).
The Nan-shan highlands have their foot on the Mongolian plateau (average altitude, 4000 ft.), i.e.
Thus, one of them is named indiscriminately Nan-shan, Richthofen Range and Momoshan.
The Nan-shan ranges run through the centre of the province from south-west to northeast, and divide it into a northern portion, the greater part of which is drained by the Tsien-tang-kiang, and a southern portion which is chiefly occupied by the Ta-chi basin.