Chemins au Deable
A road, said to be haunted by devils, which led through the Forest of Misadventure and into the Valley of No Return (Val Sans Retour). It was somewhere not far from the castle of Gais on the Thames.
Galescalain (Galeshin), Arthur’s duke of Clarence, traveled the road despite various warnings, and later had to be rescued by Lancelot. Lancelot heard strange voices but saw nothing.
Source
Vulgate Lancelot | 1215-1230