In Northwestern China, a great range crosses the Yellow river, in its course between Shansi and Shensi, and trending N. E. by E., connects the mountain knot of Northwestern Sz'chuen with that of the Ourang daban north of the Tushïkau gate of the Great Wall. Nearly parallel to this is another range which, beginning west of Singan (fu), crosses the Yellow river, forming the Lungmun gorge, and traversing, obliquely, the centre of Shansi, gradually approaches the other range in northern Chihli.