The Ordos Desert forms an intermediate step in the descent from the Himalayas to the lowlands of eastern China. Towards the south it rises to an altitude of over 1,500 m, and in the west, along the right bank of the Yellow River, the Arbus or Arbiso Mountains, which overlie the steppe by some 900 m, serve to link the Helan Mountains with the Yin Mountains. The northern part of the great bend of the Yellow River is filled with the sands of Kuzupchi River, a succession of dunes, 12-15 m high. In some places these sand-dunes approach close to the Yellow River; in others they are parted from it by a belt of sand, intermingled with clay, which terminates in a steep escarpment, 15 m and in some localities 30 m above the river.