Geology meets archaeology: rediscovering the life and work of Geoffroy d’Ault du Mesnil (1842–1921)

The period between the middle of the nineteenth century and the beginning of the twentieth century saw the birth and consolidation of prehistory and archaeology as scientific disciplines. Discussions of method and theory were posed; the antiquity of humankind was demonstrated; stratigraphic and chrono-typological sequences were settled. This process was initially linked to the natural and geological sciences. In France the names of J. Boucher de Perthes, E. Lartet, A. de Lapparent, E. Piette, E. Cartailhac, G. de Mortillet, L. Capitan and H. Breuil appeared; their role in the development of research frameworks at the national, European and international scales is well known, and they have been the subject of detailed studies in the historiography of geology and/or archaeology. However, the name of one of the most influential characters of the period seems to have been forgotten. This paper attempts to reassess the scientific standing and explore the personal life of Geoffroy d’Ault du Mesnil (1842–1921) through first-hand analysis of a variety of sources. The paper analyses the origins of his interdisciplinary approach to science, how he came to be a leading expert on the Quaternary terraces of the valley of the Somme and his key role in research on, and the preservation of, France's prehistoric heritage. This ultimately permits a renewed understanding of d’Ault du Mesnil's contribution to the scientific development of geology and prehistory, in addition to demonstrating how the wider social, economic and political context of the time shaped his own scientific personality.