Lower terrace is fringed by a massive border-range - the Khinganwhich runs in a north-easterly direction from the Great Wall of China to the sources of the Nonni-ula, A narrow alpine region (40 to 50 m.), consisting of a series of short secondary chains parallel to the border-range, fringes this latter on 'its eastern face.
Beyond that it swells out into the vast massif of Anambaruin-ula, which is traversed by at least three minor parallel chains.
But on the east of the Anambaruin-ula it once more contracts to two main ranges, the more southerly being that which Przhevalsky called the Humboldt Range (crossed by a pass at 13,200 ft.).
The next succeeding parallel range, the Koko-shili, which is continued eastwards by the Bayan-khara-ula, between the upper headstreams of the Hwang-ho or Yellow River and the Yangtszekiang, belongs orographically to the plateau of Tibet.
AIGUN, or Aihun (also Sakhalyan-ula-khoto), a town of China, province Hei-lung-kiang, in northern Manchuria, situated on the right bank of the Amur, in a fertile and populous region, 20 m.