MISSISSIPPIAN PERIOD

in North America, interval of geologic time roughly equivalent to what is internationally designated the Early Carboniferous epoch (360 to 320 million years ago). Because the rocks associated with this period are typified by those in the Mississippi valley region (where the strata consist largely of very fossiliferous marine limestones), some American geologists prefer the designation Mississippian to Early Carboniferous, which was introduced in Europe. See Carboniferous period.