Cambrian-Ordovician boundary on the southern Liaodong Peninsula

Fossils of species such as Saukia and Calvinella were first found in the upper part of the Cam-brian-Ordovician Yeli Formation at Erlongshan and Changlingzi,Changxing Island Township,Wafangdian City,southern Liaoning.Then the Saukia-Calvinella assemblage zone was established and determined to be a fossils zone at the topmost part of the Late Cambrian Fengshan Stage.In addition,the microfossil of Ueahconus beimadaoensis was collected above this zone.The species is also an Early Ordovician index el-ement.On that basis the Cambrian-Ordovician boundary in southern Liaoning was revised.