When the geologic time periods were being named ... 359 million to 323 million years ago, and the later Pennsylvanian Period (named for rocks in that state) 323 million to 299 million years ...

This time period took place 359 to 299 million years ... (359.2 million to 318.1 million years ago) and the later Pennsylvanian (318.1 million to 299 million years ago). During the Mississipian ...