Sevenoaks (Kent) reverse
Medium: Pen and ink on paper
Drawing on the reverse side of OSD 100 pt.1 (folio V, serial no. 353).
Only the skeleton of a drawing is presented here. Pencil lines radiate from fixed points, representing angular measurements taken from trigonometrical stations. Churches were often chosen for such stations, due to the clear views afforded by their tall towers or spires. On this map, an outlined red cross indicates a church, 'St Clements', with a windmill nearby.