His interest in geology and its allied sciences was catholic, as expressed in two hundred or so articles and twelve books. He excelled in compilative writing, as seen in books such as The slates of Wales (1925); Coal, and the coalfields in Wales (1926); The evolution of the Bristol Channel with special reference to the coast of South Wales (1929); Limestones, their origins, distribution, and uses (1930); Studies in the origin of the scenery of Wales, 1 — The river scenery at the head of the Vale of Neath (1930); and, with Bruce Campbell and Richenda Scott, Snowdonia: The National Park of Wales (1948). He paid particular attention to the study of maps: his published works include Geological maps: their history and development, with special reference to Wales (1928); The map of Wales [before 1600 A.D.] (1935); and Humphrey Lhuyd's maps of England and Wales (1937), which remains the definitive monograph.

He was one of the most active historians of geology of his time. Each of his compilative books contains a wealth of historical material and he also wrote monographs on a number of the nineteenth-century pioneers of geology — W.D. Conybeare (DWB, 81), Dean William Buckland, Charles Lyell and particularly H.T. de la Beche, founder of the Geological Survey of Great Britain, the Museum of Practical Geology and the Royal School of Mines. He contributed many items to DWB. He maintained an active interest in the history of industry in Wales, particularly the extractive industries, and in essence was the founder of the Department of Industry which was formed at the National Museum in 1958. He was always interested in the connection of geology with other subjects, as seen in The stones of Llandaff Cathedral (1958), Sunken cities, some legends of the coast and lakes of Wales (1957) and Mining for metals in Wales (1962).

He was a proficient curator who built up the Department of Geology at the National Museum and who wrote a great deal on the work of a museum curator, including a standard guide, Geology in museums (1939). He was a keen advocate of the museum profession — a long-serving Council member of the Museums Association, President in 1952-53, for many years Chairman of the Education Committee, architect of the Association's first Diploma, member of the Joint Committee with the Carnegie United Kingdom Trust; he was also a member of the National Co-operative Body for Museums for UNESCO. He was above all an ardent educator and proselytizer of his subject, an indefatigable lecturer, reviewer and annalist. He acted regularly as a consultant geologist for public bodies on water conservation projects and on quarrying ventures, and his contributions were recognised as President (and winner of the Gold Medal) of the South Wales Institute of Engineers, as an Honorary Fellow of the Institute of Quarrying and the Permanent Way Institute and as a member of a Committee on the slate industry appointed by the Ministry of Works.

He was awarded a D.Sc. by the University of London in 1920 for research work on fossil brachiopods, an O.B.E. in 1949 ‘for services to science in Wales’, and an Honorary D.Sc. in the same year in the citation for which is stated: ‘For him a museum is essentially an interpreter's house’.

He m. Ellen M. Pierce, Ticehurst, in May 1915. He d. 23 July 1968 at 19 Chargot Road, Cardiff.