A book that I have "Reminiscences of Exeter" published in 1878 lists the executions in Devonshire since 1794, however it also states that "before the goal was built the executions for the county were held at Ringwell, about two miles on the London road. The prisoners were taken through Heavitree in carts, each sitting on a coffin. After they were cut down they were buried near the same spot" This explains the previous posting that bones were found in this area.
Silvertonhistory