In the United States, the Carboniferous Period is generally divided into the Mississippian and Pennsylvanian Periods. The name "Carboniferous" refers to the abundance of coal found in strata of this age. The Pennsylvanian Period (from the state of Pennsylvania, where many fossils of this age are found) stretched from about 323 mya until 290 mya.
The warm, moist climate of the Carboniferous was ideally suited for the dense forests that left their remains, and also for the amphibians and insects that diversified and radiated throughout the world during the time.
Classic Fossil-Bearing Sites
Joggins
Formation, Nova Scotia
Edinburgh Coal Beds, Scotland
Anthracite Coal Beds, eastern U.S.
No major impact sites of Pennsylvanian age are known.
Significant Events
Orogeny
The Pennsylvanian was a time of mountain building. The Appalachians in the eastern U.S. began to rise, an uplift that continued into the Permian. The Ancestral Rockies rose in Colorado, Wyoming, and Utah, and another mountain chain along the New Mexico/Arizona border.
Coal Swamps
During most of the Pennsylvanian, a large portion of North America supported lush, swampy forests. Lycopods, scale trees, made up the largest component of these forests, with some of these trees reaching 100 feet in height. Some ferns grew to 50 feet.
Insects and amphibians thrived in this environment. Meter-long amphibians were common, as well as a dragonfly with a 75 cm wingspan and a 4-inch cockroach.
First Reptiles
The first reptiles are found in Upper Mississippian/Lower Pennsylvanian rocks in Nova Scotia. By creating the amniote egg, with a strong, waterproof shell, reptiles were able to fully leave the aquatic environment to live entirely on land.
Pennsylvanian Graphics
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| Lepidodendron |
Sigillaria |
Amphibian |
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| Pennsylvanian forest |
Dragonfly |
Fern |
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| Pecopteris |
Plant stem |
Lepidodendron |
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