Mississippian (geology)
It is the earlier of two subperiods of the Carboniferous period lasting from roughly 358.9 to 323.2 million years ago.As with most other geochronologic units, the rock beds that define the Mississippian are well identified, but the exact start and end dates are uncertain by a few million years.[6] In North America, where the interval consists primarily of marine limestones, it is treated as a geologic period between the Devonian and the Pennsylvanian.The USGS geologic time scale shows its relation to other periods.Besides Europe and Russia, there are many local subdivisions that are used as alternatives for the international timescale.