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The Mississippian 2

The Mississippian was a period of marine ingression in the Northern Hemisphere: the ocean stood so high only the Fennoscandian Shield and the Laurentian Shield stood above sea level. The cratons were surrounded by extensive delta systems and lagoons, and carbonate sedimentation on the surrounding continental platforms, covered by shallow seas. In North America, where the interval consists primarily of marine limestones, it is treated as a geologic period between the Devonian and the Pennsylvanian. During the Mississippian an important phase of orogeny occurred in the Appalachian Mountains. It is a major rock building period named for the exposures in the Mississippi Valley region. The USGS geologic time scale shows its relation to other periods