Their maximum elevation is about 350 metres above sea level (NN).
In these muschelkalk hills lies the Pyrmont Basin (Pyrmonter Talkessel) on the fault lines of which mineral and brine springs rise, and to which the town of Bad Pyrmont owes its status as a spa town.
On the hill of Pyrmonter Berg is the only large area of deciduous forest.
In spite of its poor soils, agriculture dominates: grasslands follow the rivers in the valleys.
The valley of the Emmer stream has been declared as a Special Area of Conservation; part of it also has nature reserve status.