Definition and global correlation of the Santonian-Campanian boundary

Review of biostratigraphical evidence from different regions shows that criteria used by workers on various marine fossil groups to define the Santonian-Campanian boundary differ considerably in relative age and position. Probably the most widely recognizable of these criteria is the extinction of the distinctive crinoid Marsupites testudinarius (North America, Europe, Asia, North Africa, Australia), which, coincides exactly with two separate definitions of the boundary. A comparison of evidence from upper Santonian and lower Campanian successions in widely separated regions allows a series of important biostratigraphical markers to be placed in correct order. -from Author