Gobi Desert from , and those of the ranges from higher, though in a few cases they reach altitudes of . The elevations do not form continuous chains, but make up a congeries of short ridges and groups rising from a common base and intersected by a labyrinth of ravines, gullies, glens and basins. But the tablelands, built up of the horizontal red deposits of the Han-gai (Obruchev's Gobi formation) which are characteristic of the southern parts of eastern Mongolia, are absent here or occur only in one locality, near the Shara-muren river. They are greatly intersected by gullies or dry watercourses.
Gobi Desert of Gobi is crossed by several trade routes, some of which have been in use for thousands of years. Among the most important are those from Kalgan (at the Great Wall) to Ulaanbaatar (); from Jiuquan (in Gansu) to Hami ; from Hami to Beijing (); from Hohhot to Hami and Barkul; and from Lanzhou (in Gansu) to Hami. The southwestern portion of the Gobi, known also as the Hsi-tau and the Little Gobi, fills the space between the great north loop of the Yellow River on the east, the Ejin River on the west, and the Qilian Mountains and