The system of rock layers deposited during the Carboniferous period

The fifth period of the Paleozoic Era, characterized by vast swamps and the formation of major coal deposits.

organic acid forming colorless crystals that turn pink in light and air, used to manufacture dyes, synthetic resins, and as a disinfectant

a layer or bed of coal in the earth's crust

Shitanjing subdistrict of [[大武口区|大武口區|da4 wu3 kou3 qu1]] in [[石嘴山市|石嘴山市|shi2 zui3 shan1 shi4]], Ningxia

Shitanjing subdistrict of Dawukou district in Shizuishan city, Ningxia