Filling under North-South Road surface, apparently to raise the level of the road as thickness of fill varies depending on height of road. Fill sits on earliest, cobbled road layer. The road surface set ... Mid-6th c. B.C ... Filling under North-South Road surface, apparently to raise the level of the road as thickness of fill varies depending on height of road. Fill sits on earliest, cobbled road layer. The road surface set upon this fill consists of cobbling to the west and a hard packed surface to the east.