Sheet 3, Boulogne, Carte Géologique Détaillée de, 1885, 2nd edition, 1:80,000 scaleSheet 3, Boulogne, Carte Gologique Dtaille de, 1885, 2nd edition, 1: 80,000 scale. Base map 1837. No issue date. Colour printed map, 62. 5 x 91cm, (with notice explicative, 62. 5 x 117cm) dissected and mounted on linen folding to 20. 5 x 13 cm.; linen folded over to protect map edges. Neat manuscript notes in pencil within notice explicative. On outside as folded, book plates of mapseller, Ch. Branger and of University College, Exeter. The Channel