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During the early part of the period, sediments were being eroded from the Acadian Mountains to the east and from the Canadian shield to the north.
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Clay, silt, and fine-grained sand settled in the Ohio sea as the offshore portion of the Catskill Delta to the east
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Supercontinent Laurasia consisted of North American and Eurasion continents.
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South America, India, Australia, Africa, and Anarctica combined to make the supercontinent Gondwana
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Low-lying parts of coninents flooded again as sea levels rose and fell.
Reef-building organisms then laid down huge deposits of calcium carbonate. They are now thick layers of limestone. -
Beginnning of Karoo ice age
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Large primitive trees develope.
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Rocks consist primarily of erosion-resistant sandstones and sandy shales that form prominent cliffs
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Forests consisting of ferns, mosses, horsetails and gynosperms.
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Tropical rainforests and swamps rich with vegetation that would later become coal beds grew on exposed land, and shallow, tropical seas covered large regions of the present-day American Midwest and South.
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Oxygen levels increase
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Vertebrates appear on land
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First winged insects appear.
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Mississippian marbles and limestones were filled with fossils of flower-like invertebrates called crinoids, intricate corals, and other Paleozoic carbonate organisms. (Now exposed throughout the American Midwest.)
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Collision between Africa and Eastern North American created the Appalachian mountains.
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Muddy seas persisted across the area that is now Ohio. They were not favorable for many bottom-dwelling invertebrates. Few were well preserved in these rocks.
