This drawing is mentioned in the Ordnance Survey Letter Book. Folio 91 records that the drawing was returned to the Tower from the Quartermaster General's Office. The circular hole in the top right-hand corner indicates that an 'Ordnance Office Copy' blind stamp has been removed. Relief is a dominant feature of this drawing, recorded by shading and interlining ('hachuring'). Trigonometrical altitudes are also recorded. Coniferous and deciduous trees are distinguished pictorially. Although recording archaeological sites was not obligatory until 1816, many draughtsmen noted these prior to this. Here an 'Ancient Fort' is shown in Trelawn, while an ancient earth bank called Giant's Hedge, possibly the boundary of a petty kingdom, is marked by a yellow line.