Pen Plaenau Roman marching camp This Roman marching camp was discovered by Hugh Toller, while overflying the area looking for the route of a Roman road. The camp occupies the south-west facing slope of Pen-plaenau, a spur of the Berwyn mountains that runs south-east between Nant Rhydwilym and Nant Ysgallog. The solid lines represent the extant remains of bank and ditch, while the dotted lines represent the interpolated continuation where the remains disappear under peat and vegetation. The McAlpine estate kindly gave their permission for the survey which was sponsored by Majors of Oswestry and Shrewsbury.