This coal-forming period of geologic time is split into Mississippian & Pennsylvanian periods
The Carboniferous is often split into two divisions, the Mississippian and 
the Pennsylvanian; in the United States the break in the geologic sequence is so
... [DOC] [TLE] The Geologic Time Scale - ScienceViews.com [PAR] An era of geologic time from the beginning of the Tertiary period to the present.