Serpukhovian
The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from 330.9 ± 0.2 Ma to 323.2 ± 0.4 Ma. It is preceded by the Visean and is followed by the Bashkirian.