I Have much pleasure in furnishing you with the accompanying rough sketch of the rock on which were discovered, some time ago, the remains of a building and its “kitchen-midden,” belonging to a remote period, and in which you took some interest in respect of its bearing upon a geological question of the day, namely, the supposed rise of our coasts within the historical period. The rock in question, situated about three miles east of North Berwick, on the south side of the Frith of Forth, is isolated at spring-tides, but is not at other times separated by the sea from the main-land.