DESOR, PIERRE JEAN ÉDOUARD (1811-1882), Swiss geologist, was born at Friedrichsdorf, near Frankfort-on-Main, on the 13th of February 1811. Associated in early years with Agassiz he studied palaeontology and glacial phenomena, and in company with J. D. Forbes ascended the Jungfrau in 1841. Desor afterwards became professor of geology in the academy at Neuchâtel, continued his studies on the structure of glaciers, but gave special attention to the study of Jurassic Echinoderms. He also investigated the old lake-habitations of Switzerland, and made important observations on the physical features of the Sahara. Having inherited considerable property he retired to Combe Varin in Val Travers. He died at Nizza on the 23rd of February 1882. His chief publications were: Synopsis des Échinides fossiles (1858), Aus Sahara (1865), Der Gebirgsbau der Alpen (1865), Die Pfahlbauten des Neuenburger Sees (1866), Échinologie helvétique (2 vols., 1868-1873, with P. de Loriol).