There is further conjecture that the original structure's course may have gone beyond Cawthorne Camp to the Roman settlement of "Derventio Brigantum" (possibly either Stamford Bridge or modern-day Amotherby near Malton). Any postulated extension further south than Cawthorn is contested. Hinderwell reports in 1811 that the late Robert King had found evidence of a continuation of the causeway between "Newsom-bridge" and Broughton (a former township located near Appleton-le-Street). Hayes and Rutter failed to find any trace of the causeway south of Cawthorn along a route via Amotherby, Barugh or Newsham in their survey in the 1950s, and note that its course could not be determined as early as 1726.