see http://www.wansdyke21.org.uk/wansdyke/wanwesteast/waneast7.htm
The Roman Road(Silchester to Bath) ran along the grey road in image.It pre-existed Wansdyke.In this image,Wansdyke comes out of the bushes,either side of the emerging Roman Road,to the point where the Road turns and you see the mound dip away.That's at the top of a coombe,which drops away 200ft.