The Mississippian was a period of marine transgression in the Northern Hemisphere: the sea level was so high that only the Fennoscandian Shield and the Laurentian Shield were dry land.

citation

Wikipedia contributors. (2023, December 19). Mississippian (geology). In Wikipedia, The Free Encyclopedia. Retrieved February 13, 2024, from https://en.wikipedia.org/w/index.php?title=Mississippian_(geology)&oldid=1190789890

Mississippian (geology) (Wikipedia) The Mississippian (/ˌmɪsɪˈsɪpi.ən/ miss-ə-SIP-ee-ən, also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. 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. The Mississippian is so named because rocks with this age are exposed in the Mississippi Valley.