The English Chalk and London Clay: two remarkable British bony fish Lagerstätten

Abstract

Abstract The Late Cretaceous (Cenomanian–Maastrichtian) Chalk Group and Eocene (Ypresian) London Clay Formation are two British marine deposits that yield globally significant assemblages of fossil actinopterygian (ray-finned) fishes. Materials from these units, especially the Chalk, featured prominently in the work of Arthur Smith Woodward. Here we summarize the history of study of actinopterygian fossils from the Chalk and London Clay, review their geological and palaeoenvironmental context and provide updated faunal lists. The Chalk and London Clay are remarkable for preserving fossil fishes in three dimensions rather than as the flattened individuals familiar from many other famous Lagerstätten, as well as capturing detailed ‘snapshots’ of marine fish faunas that bracket the major taxonomic shift that took place near the Cretaceous–Palaeogene boundary.