The thin but widespread Cornbrash Formation is a marine sedimentary deposit of particular interest and importance to stratigraphers because, as revealed by its palaeontology, within it lies a transgressive event which marks the boundary between the Middle Jurassic Bathonian and Callovian stages. The monographic treatment of its varied fauna was started by John Frederick Blake (1839-1906), but he died before the work was completed, and it remained unfinished. This one-volume reissue comprises the two parts that were originally published separately. Part 1 (issued in November 1905) includes details of Cornbrash exposures from Dorset to Yorkshire, and systematic descriptions of the vertebrates (reptiles, crocodiles, fish) and molluscs (nautiloids, ammonites, belemnites and gastropods). The second part (issued posthumously in December 1907) continues to cover the molluscs (scaphopods) and draws the monograph to a premature close. Some seventy taxa are illustrated in nine lithographic plates.