Thence the boundary describes a sinuous line, following the Great Wall, and thus includes the Ordos (Ho-tau) and Alashan (Si-tao), and reaches its most southern point in 36° 40' N., 104° 20' E.
Crossing the Hwang-ho, they advanced into the terrible sandy tract known as the Ordos Desert.
The valley of the Wei, situated between high tableland (the Ordos plateau) on the north and rugged mountains to the south, forms the great channel of communication between Eastern China and Central Asia.
Between November 1870 and September 1873, accompanied by only three men and with ridiculously small pecuniary resources, he crossed the Gobi desert, reached Peking, and, pushing westwards and south-westwards, explored the Ordos and the Ala-shan, as well as the upper part of the Yangtsze-kiang.
The southern chain bears the names of Karaadzirga and Burkhan-ola, and terminates in about 99 0; but the northern range, the principal names of which are Artsi-bogdo and Saikhat, extends probably most of the way to the great northward bend of the Hwang-ho or Yellow River round the desert of Ordos.