Hadrian’s Wall, Vallum or Fosse
Segment II
Pons Aelius to Condercum
Newcastle upon Tyne to Benwell
Mile castles: 4 to 7
Built: 122-128
This area has been completely overbuilt and there are no traces of the wall to be seen except for the reconstructed Vallum crossing at Condercum.
Built: after 128, dating uncertain
What is commonly called the “Vallum” was a wide ditch flanked by earthen ramparts that ran behind Hadrians wall. Its purpose remains uncertain as it is unique to Roman border fortifications. Possibly it was to define the military zone of the wall and to force trade and transport to follow marked roads to gates in the wall. In many places, it is more visible than the wall itself. This area has been completely overbuilt and there are no traces of the wall to be seen except for the reconstructed Vallum crossing at Condercum.
See: http://structuralarchaeology.blogspot.com/2010/11/40-reverse-engineering-vallum.html
https://en.wikipedia.org/wiki/Vallum_(Hadrian%27s_Wall)