Leonard Horner and an enthusiasm for Loess: [Leicester Studies in the History of Loess Research part I]

Abstract Leonard Horner (1785–1864) made substantial contributions to the study of loess. He made field trips with J.J. Noeggerath and Charles Lyell and published useful material on the loess near Bonn. He was an unappreciated pioneer- he was the first person to direct attention to loess as a material. He pointed out that loess was intrinsically interesting. He studied the material transported by the Rhine, and the alluvial deposits in Egypt, looking for links to loess, and the problem of loess formation. He was born in Edinburgh in 1785 and directed the thoughts of young Charles Darwin towards science when he came to Edinburgh to study medicine. Circumstances placed him in Bonn in the critical years 1831–1833; in this time Charles Lyell married his eldest daughter Mary; and both Lyell and Horner encountered the loess. Lyell made it well known via vol.3 of the Principles of Geology, Horner became a loess enthusiast. In the summer of 1833 Horner & Lyell were in the crater of the Roderberg considering the more than 20 m of loess deposited there. His major paper was published in 1836 (reporting the Roderberg excursion) and he joined Lyell’s list of loess investigators in the 5th edition of the Principles published in 1837. He was the last to join that select eleven: Bronn, Leonhard, Boue, Voltz, Steininger, Merian, Rozet, Hibbert, Noeggerath, von Meyer, Horner. Most of these were writing on the geology and landscapes of the Rhine valley, but Horner was drawing attention to the amazing nature of the loess itself, in particular the spectacular disaggregation on contact with water. He also published the first geological map of the Bonn region, including the Roderberg and the Siebengebirge, a region of loess and volcanoes.