Life of the Pennsylvanian

The state of Pennsylvania, USA is known for its coal deposits, from which the name of the time period is taken. Extensive swamps covered much of North America at this time, as land plants rose to prominence. The Pennsylvanian also saw the evolution of several groups of insects, which had appeared in the Devonian. The oldest winged insects known date from the Pennsylvanian, and included such familiar groups as the mayflies, dragonflies, and cockroaches, as well as insects now extinct. One such organism, a millipede from Mazon Creek, Illinois, is depicted above right.

In the oceans, brachiopods, tabulate and rugose corals, and crinoids dominated, along with giant foraminiferans known as fusulinids. Fusulinids could reach a centimeter in length, and were abundant enough to form sizable deposits of rock, known as "rice rock" because of the resemblance between fusulinids and rice grains.