 Mississippian

The Mississippian is the earlier subperiod of the Carboniferous, following the Devonian and ending at the beginning of the Pennsylvanian. It spans roughly 359 to 323 million years ago. The corresponding body of rocks is the Mississippian subsystem.^[ref]

For example, a Mississippian fossil is older than a Pennsylvanian fossil, even though both may be labelled Carboniferous. This subdivision makes broad comparisons more informative without requiring an exact numerical age for each specimen. A numerical boundary age is an estimate on a calibrated time scale; the named subdivision also depends on agreed stratigraphic definitions.