Archean.—Gneiss, crystalline schists, phyllites, crystalline limestones. Exposed in Liao-tung, Shan-tung, Shan-si, northern Chih-li and in the axis of the mountain ranges, e.g. the Kuen-lun and the ranges of southern China.
Sinian.—Sandstones, quartzites, limestones. Sometimes rests unconformably upon the folded rocks of the Archaen system; but sometimes, according to Lóczy, there is no unconformity. Covers a large area in the northern part of China proper; absent in the eastern Kuen-lun; occurs again in the ranges of S.E. China. In Liao-tung Cambrian fossils have been found near the summit of the series; they belong to the oldest fauna known upon the earth, the fauna of the Olenellus zone. It is, however, not improbable that in many places beds of considerably later date have been included in the Sinian system.
Ordovician.—Ordovician fossils have been found in the Lung-shan, Kiang-su (about 50 m. east of Nan-king), in the south-west of Cheh-kiang and in the south-east of Yun-nan. Ordovician beds probably occur also in the Kuen-lun.
Silurian.—Limestones and slates with Silurian corals and other fossils have been found in Sze-ch‘uen.
Devonian.—Found in Kan-suh and in the Tsing-ling-shan, but becomes much more important in southern China. Occurs also on the south of the Tian-shan, in the Altyn-tagh, the Nan-shan and the western Kuen-lun.
Carboniferous.—Covers a large area in northern China, in the plateau of Shen-si and Shan-si, extending westwards in tongues between the folds of the Kuen-lun. In this region it consists of a lower series of limestones and an upper series of sandstones with seams of coal, which may perhaps be in part of Permian age. This is probably the most extensive coalfield in the world.
In south China the whole series consists chiefly of limestones, and the coal seams are comparatively unimportant. Carboniferous beds are also found in the Tian-shan, the Nan-shan, Kan-suh, on the southern borders of the Gobi, &c.
Mesozoic.—Marine Triassic beds containing fossils similar to those of the German Muschelkalk have been found by Lóczy near Chung-tien, on the eastern border of the Tibetan plateau. Elsewhere, however, the Mesozoic is represented chiefly by a red sandstone, which covers the greater part of Sze-ch‘uen and fills also a number of troughs amongst the older beds of southern China. No marine fossils are found in this sandstone, but remains of plants are numerous, and these belong to the Rhaetic, Lias and Lower Oolite. No Cretaceous beds are known in China excepting in S. Tibet (on the shores of the Tengri-nor) and in the western portion of the Tian-shan.
Cainozoic and Recent.—No marine deposits of this age are known. Although the loess of the great plain and the sand of the desert are still in process of formation, the accumulation of these deposits probably began in the Tertiary period.