St. Columb Major, Cornwall
Draughtsman: Dawson, Robert
Medium: Pen and ink on paper
This drawing is orientated toward the south-east. On its reverse, obscured by backing material, is a triangulation diagram used to plot locations accurately. Tin and copper mines are marked, and a key to the symbols used to distinguish them is given at the bottom of the drawing.
"Harmony Cot" is marked as the birthplace of the portrait painter, John Opie (1761-1807). The inclusion of such information seems at odds with the Survey's military emphasis, but it does reflect the interests and training of the draughtsmen, many of whom were professional artists. To the north of St Columb Major lies the ancient monument known as the Nine Maidens, symbolised by a drawing of stones. A dot, annotated "point", appears in the bottom left hand corner of the map. This is probably the coastal station at Trevose Head, a base for the measurement of angles of elevation.