Wuzhen is a river alluvial plain with a lot of swamp silt, so its veins are higher than those of No.4 Mine, and its color is deep and fat, so it is named Wu Dun. In fact, such place names are not uncommon in the local area. 9 kilometers away from Wuzhen, there is a village called Hongdun. Its town motto says, "Hongdun is in the west of the town, and the ground is full of graves. The village is named after this. " There is also a village called Zidun next to it, because it is purple stone soil. The names of Hongdun and Zidun provide realistic basis for the vivid description of Wu Dun's name.