Karl Caesar von Leonhard (1779–1862), and the beginnings of loess research in the Rhine valley

The term ‘Loess’ entered the scientific vocabulary in 1824 in section 89 of ‘Charakteristik der Felsarten’ by Karl Caesar von Leonhard (a two page definition and description, plus details of a few locations). The term had been used before 1824, but Leonhard places it firmly into the literature. There were alternatives; Leonhard made a choice. Interest in loess developed in the early 1820s, perhaps in association with interest in the geology of the Rhine volcanoes. Possibly the first fairly detailed study of loess was by H.G. Bronn in 1830. After 1830 Hibbert, Horner and Lyell carried forward the study/appreciation of loess in English. Charles Lyell (in Principles of Geology) listed ten pioneers: Bronn, Leonhard, Boue, Voltz, Noeggerath, Steininger, Merian, Rozet, Von Meyer and Hibbert. Early ideas of loess formation emphasized the role of deposition from water, perhaps influenced by the advocacy of Boue for continent wide inundations. Leonhard was an important figure and deserves his position as the most significant loess pioneer. Lyell was largely responsible for the spread of interest in loess, via The Principles of Geology.