Vorlisgion

A river in the far northern Flatlands that runs at the feet of the Dymerian and Dark Mountains. The river flows predominantly over the plains, and then drops down into subterranean waterways that flow up again into the mountains of Dymeria. It's fingers have many below ground systems and cavernous riverways. 
The city of Dymeria lies in the mountains along the river.
Also: Volisgion