Single sheet. Col. ms. Scale: [ca.1:45 000 (bar)]. Cartographic Note: North at 292 degrees. Ungraduated. Scale in miles. Additional Places: San Fiorenzo, Mortella ['Martello'] Tower, Bastia. Contents Note: Key with extensive notes on the fortifications, and dispositions of troops and guns. It is inscribed as 'communicated' by General David Dundas, the British land commander of the 1794 invasion of Corsica, and is presumably by someone on his staff. Another inscription in the same hand at top left shows it appears to have been sent to his half-cousin Henry Dundas, later 1st Viscount Melville, Home Secretary from 1792 and then Secretary of State for War from July 1794.