The MN zonation is a system used to correlate mammal-bearing fossil localities in the Miocene and Pliocene epochs of Europe. It consists of sixteen consecutive zones (numbered MN 1 through MN 17; MN 7 and 8 have been joined into MN 7/8) defined through reference faunas, well-known sites that other localities can be correlated with.
The zones are as follows:
References
MN zonation Wikipedia(Text) CC BY-SA