 Whilst the majority opinion among archaeologists is that the structure is a bridge, an alternative interpretation has been proposed by amateur archaeologist Raymond Selkirk, who contends that the structure is a navigation dam with an overspill channel.From this, and other evidence he argues that the Romans made far greater use of river transport than is generally recognised.His views are set out in his books "The Piercebridge Formula" (1983), "On the Trail of the Legions" (1995) and "Chester-le-Street & Its Place in History" (2000).