The watershed between the Yangtsze-kiang and that of the Si-kiang is less clearly marked. It traverses the immense tableland which occupies a great part of the south-west provinces of Yun-nan and Kwei-chow and is continued eastward by the lower tableland of Kwang-si and the Nanshan hills (whose elevation seldom exceeds 6000 ft.). The basin of the Yangtsze-kiang forms the whole of central China. Its western border, in Sze-ch'uen and Yun-nan, is wholly mountainous, with heights exceeding 19,000 ft. Central Sze-ch'uen, which is shut in by these mountains on the west, by the Yun-nan and Kwei-chow plateau on the south, by the Kiu-lung range on the north, and by highlands eastward (save for the narrow valley through which the Yangtsze-kiang forces its way), is a vast red sandstone tableland of about 1600 ft. elevation. It is exceedingly fertile and supports a dense population. Eastward of Sze-ch'uen the Yangtsze valley is studded with lakes. Finally it enters the deltaic plain. The basin of the Si-kiang fills the two southern provinces of Kwang-si and Kwang-tung and contains no very striking orographic features. It may be added that in the extreme S.W. portion of China is part of a fourth drainage area. Here the Mekong, Salween, Song-koi (Red river), &c. flow south to Indo-China.
_The Coast_.--The coast-line, following all the minor indentations, is reckoned at over 4500 m.; if only the larger inlets and promontories be regarded, the coast-line is about 2150 m. in length. Its shape is that of a semicircle, with its most easterly point midway (30° N.) between its northern and southern extremities. At either end of this semicircular sweep lies a peninsula, and beyond the peninsula a gulf. In the north are the peninsula of Shan-tung and the gulf of Chih-li; in the south the Lien-chow peninsula and the gulf of Tongking. Due south of Lien-chow peninsula, separated rom it by a narrow strait, is Hai-nan, the only considerable island of China. From the northern point of the gulf of Chih-li to 30° N., where is Hang-chow bay, the shores are flat and alluvial save where the Shan-tung peninsula juts out. Along this stretch there are few good natural harbours, except at the mouths of rivers and in the Shan-tung promontory; the sea is shallow and has many shoals. The waters bordering the coast of Chih-li are partly frozen in winter; at 10 m. from the shore the water is only 20 ft. deep. The proximity of Peking gives its few ports importance; that of Taku is at the mouth of the Peiho. In Shan-tung, deeply indented on its southern coast, are the ports of Chi-fu, Wei-hai-wei and Tsing-tao (the last in Kiao-chow bay). South of Shan-tung and north of the mouth of the Yangtsze huge sandbanks border the coast, with narrow channels between them and the shore. The estuary of the Yangtsze is 60 m. across; it contains islands and sandbanks, but there is easy access to Wusung (Shanghai) and other river ports. The bay of Hangchow, as broad at its entrance as the Yangtsze estuary, forms the mouth of the Tsien-tang-kiang. The Chusan and other groups of islands lie across the entrance of the bay.