the road heads straight for Silbury for some way then takes a sudden right turn to negotiate Waden hill.
It couldn't sweve too far right as it would have hit the flood plain of the river.
That end of Waden once had numerous saucer barrows which have since been ploughed out.
A lot of the barrows around the Sanctuary were found to be Romano-British so might not have been there at the time the road was built.