Pennsylvanian Subperiod

Carboniferous Period.The Carboniferous Period began approximately 358.9 million years ago and ended 298.9 million years ago.

Pennsylvanian Subperiod, second major interval of the Carboniferous Period, lasting from 323.2 million to 298.9 million years ago. The Pennsylvanian is recognized as a time of significant advance and retreat by shallow seas. Many nonmarine areas near the Equator became coal swamps during the Pennsylvanian. These areas are mined for coal today. See Carboniferous Period.

This article was most recently revised and updated by John P. Rafferty.
Citation Information
Article Title: Pennsylvanian Subperiod
Website Name: Encyclopaedia Britannica
Publisher: Encyclopaedia Britannica, Inc.
Date Published: 08 May 2017
Access Date: February 22, 2025