Global Boundary Stratotype Section and Point
The base of the Campanian stage is defined as a place in the stratigraphic column where the extinction of crinoid species "Marsupites testudinarius" is located. (A Global Boundary Stratotype Section and Point or GSSP had not yet been ratified as of 2009: one possible candidate is a section near a dam at Waxahachie, Texas.) The top of the Campanian stage is defined as the place in the stratigraphic column where the ammonite "Pachydiscus neubergicus" first appears.