The Guzhangian is an uppermost stage of the 3rd series of the Cambrian. It follows the Drumian stage and precedes the Paibian stage of the Furongian series. The base is defined as the first appearance of the trilobite Lejopyge laevigata around million years ago. The Guzhangian-Paibian boundary is marked by the first appearance of the trilobite Glyptagnostus reticulatus around million years ago.