Mollusc is a collective term for all fossils of the phylum Mollusca. There are ten classes in this phylum: Monoplacophora, Polyplacophora, Aplacophora, Scaphopoda, Rostroconchia, Gastropoda, Bivalvia, Cephalopoda, Tentaculita and Hyolitha. China has abundant and widespread mollusc fossils. In Chengjiang in Yunnan Province, there are four genera and four species of Chengjian mollusc fossils, represented by Hyolithoid. The Chiting Formation in the Xinhua hilly region of Taiwan contains abundant mollusc fossils, including Chlamys, Placenta, Oystrea, Cerithium, Turritella filiola and Limopsis species. The Ordovician Cephalopod fossils found in the Three Gorges Region in Hubei Province have straight or coiled, 2–6 m long, with knotted, tumorous and vertical lines on the surface.