The bastion and Medieval town wall adjacent to it were built partly on the foundations of the Roman town wall and partly on the natural yellow sand. The Roman foundation had given way, possibly owing to the proximity of the ditch outside and the wall had tilted outwards, opening a large crack in the foundations. The fall was probably in Medieval times. When the wall was rebuilt the Roman rampart was cut back. The gap between wall and rampart was filled with black topsoil, partly from the rampart itself. This black soil and a layer above contained mostly Roman material. <1> <2> <3>