The Great South Stream is a broad stream, just a little smaller than a true river, graced with many tributaries. This waterway flows under the mountains separating Mossflower Woods from Salamandastron, including Bat Mountpit, and eventually drains into the Great Inland Lake. The stream current can be very fast in some areas and requires expert navigation to manage its waters like Duddle Pollspike. The stream also used to be frequented by a snake and a newt who bothered Martin the Warrior and his companions until the reptiles were chased away by Big Club.