The cliffs of Dover are shown almost pictorially on this plan; with dark striations indicating steepness. Relief is shown elsewhere by shading and interlining (鈥榟achuring'). Field boundaries are observed. The sandy coast is represented by a speckled pattern and grassland by a green wash. Dover Castle is seen in plan; with dark hachure lines depicting the steep underlying rocks. The castle; known as the 鈥楰ey to England'; was a site of unique strategic importance; affording the shortest crossing point of the English Channel to continental Europe.1797.OSD 106London; British Library.