108.12m above the base of the Huayansi Formation at the base of an 8 cm thick layer of dark gray calcisiltites28.2 m in Duibian B sectionDuibian B section, Zhejiang province, ChinaFAD of agnostid trilobite Agnostotes orientalis and the FO of polymerid trilobite Irvingella angustilimbataStratotype Point Base of JiangshaniantrueRatified 2011