This coal-forming period of geologic time is split into Mississippian & Pennsylvanian periods
THE 
U.S.... [DOC] [TLE] Bedrock Geology of Ohio - Ohio History Central [PAR] No rock record is preserved in Ohio after the early part of the Permian Period, 
about 295 ... is the longest segment of geologic time, ranging from the formation 
of the earth 4.6 ... that is, the continent did not completely split into two separate 
masses.