| Marine | ||
| Veldhoven Formation VE | Someren Member VESO | |
| Voort Member VEVO | ||
| Wintelre Member VEWI | ||
| Rupel Formation RU | Bilzen Member RUBI | Berg Member RUBIBE |
| Kerniel Member RUBIKE | ||
| Kleine Spouwen Member RUBIKS | ||
| Boom Member RUBO | Brinkheurne Member RUBOBR | |
| Winterswijk Member RUBOWI | ||
| Eigenbilzen Member RUEB | ||
| Ratum Member RURA | Ootmarsum Member RURAOO | |
| Tongeren Formation TO | Goudsberg Member TOGO | |
| Klimmen Member TOKL | ||
| Zelzate Member TOZE | Bassevelde Member TOZEBA | |
| Ruisbroek Member TOZERU | ||
| Watervliet Member TOZEWA | ||
The Middle North Sea Group (abbreviation: NM) is a group of geologic formations in the Dutch subsurface, part of the North Sea Supergroup. The three formations of this group form a thick sequence of sediments in the Dutch subsurface, they crop out in parts of the southern Netherlands. The Middle North Sea Group was deposited from the late Eocene to late Oligocene, between 37 and 23 million years ago.
Its three formations are (from old to young) the Tongeren, Rupel and Veldhoven Formations. The Tongeren Formation has a continental to paralic facies, the other two consist mainly of shallow marine clays and sands.