Introduction to the "Changxing Limestone" Protection Monument: The "Changxing Limestone" Protection Monument This is a "Changxing Limestone" protection monument in Chinese and English. Changxing limestone is a special term in geology. It is synonymous with the "continuous geological section from the Permian to the Triassic". It was named by the famous American geologist Gripp in 1931 and has been recognized by the world.