Saltmarsh Area Mines

Saltmarsh Area Mines were a network of Dwarven mineshafts near the town of Saltmarsh.
In The Remaining Realm, Dwarven miners found the living head of Elder King Erysicthon in a black box.
In Amalgam, John, Dordal, and Redcap found a branch of this mineshaft extending halfway through the Dreadwood. Inside of the mine they found several skeletons who had been defeated by Dwarves.