The Royal coat of arms over the chair is carved in oak from timber originally built into Westminster Hall in 1399.
The tunnel bent around the hills, occasionally descending underground, occasionally passing across timbers built over washouts.
It is thought that a mixture of large timber built round houses and straight-sided structures occupy the interior.
Although it appears to be an arch, it is composed entirely of straight timbers built to an unusually sophisticated engineering design, hence the name.
Drawing near they saw a tall manse of dark timber, built to a style elegant and stately, with many narrow glass windows, turrets and cupolas, as well as a dozen elaborate follies and crotchets included apparently for the sheer relief of boredom.
Near the shore was a short, squat building made of timbers, built into the side of a small, and clearly artificial hill.