Paleontology and geology
Rocks of this time interval are poorly exposed at the surface in Mississippi, although drill cores indicate that some Carboniferous rocks lie buried beneath much younger sediments in the northern part of the state. A small exposed area does exist in the extreme northeastern corner of the state, and Carboniferous rocks across the border in Alabama suggest that during the Early Carboniferous (Mississippian), shallow seas also covered northern Mississippi. These seas were home to molluscs, crinoids, brachiopods, and trilobites.
In the Late Carboniferous (Pennsylvanian) tectonic activity resulted in a mountain-building event (Alleghenian Orogeny) and the formation of the Southern Appalachian Mountains. Subsequent erosion of these mountains produced vast amounts of sediments that were swept into the sea, creating broad coastal plains where forests of primitive trees and fern-like plants thrived.