The Global Stratotype Section and Point (GSSP) for the base-Changhsingian Stage is defined at the First Appearance Datum (FAD) of the conodont Clarkina wangi within the lineage from C. longicuspidata to C. wangi at a point 88 cm above the base of the Changxing Limestone in the lower part of Bed 4 (base of 4a-2) at Meishan D section, Changxing County, Zhejiang Province, South China.