Definition for Pennsylvanian
From Biology Forums Dictionary
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods (or upper of two subsystems) of the Carboniferous Period.
From Biology Forums Dictionary
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods (or upper of two subsystems) of the Carboniferous Period.