The Pliocene-Pleistocene Crags of East Anglia are an incredibly rich source of fossil shells, many belonging to extant Boreal and Mediterranean genera. Dominated by marine gastropods and bivalves, the deposits also contain evidence of terrestrial and non-marine gastropods and bivalves, brachiopods, and extensive epifauna including bryozoans. Published between 1848 and 1879 in four volumes, the latter two being supplements with further descriptions and geological notes, this monograph by Searles Valentine Wood (1798–1880) covers more than 650 species and varieties of fossil mollusc. For each species Wood gives a synonymy, diagnosis (in Latin), full description, dimensions, occurrence and remarks. The supplements also provide a breakdown of the species and their current distribution. The detailed plates were prepared by the conchologist George Brettingham Sowerby and his namesake son. Volume 3 (1872–4) comprises the first supplement, covering univalves and bivalves, and includes an important map of the Crag district.