Attached to the Department of Geology in the British Museum (Nat Hist) for research on the fossil Cephalopoda (Ammonoids and Nautiloids) and the arrangement of that collection; and generally consulted by palaeontologists and Institutions for identifying fossils in these groups. Distinguished for his original studies of Mesozoic Ammonites, in which subject he is the leading authority. Has formulated original and clarifying theories of the phylogenetic relations of the Cephalopoda in general and of the Jurassic and Cretaceous ammonites in particular. His work has resulted in many important elucidations of inter-continental stratigraphical correlation and has done much to advance precise geological knowledge. Author of important monographs on Jurassic Cephalopoda of Cutch ('Palaeontologica Indica', 1927) and the Ammonoidea of the Gault of England (Palaeontographical Society); also the Jurassic and Liassic Ammonites (British Museum Catalogue, 1934 and 1938). Has published more than 100 papers and monographs.