GUETTARD, JEAN-TIENNE

born Sept. 22, 1715, tampes, Fr. died Jan. 6, 1786, Paris French geologist and mineralogist who was the first to survey and geologically map France and to observe the exposed bedrock of the Paris Basin. The keeper of the Duc d'Orlans's natural history collection, Guettard was the first to identify several fossil species from the Paris area and to suspect the volcanic origin of mountains in central France. He wrote Mmoire et carte minralogique sur la nature et la situation des terrains qui traversent la France et l'Angleterre (1746; Mineralogical Memoir and Map on the Nature and Location of the Terrains That Traverse France and England) and Atlas et description minralogiques de la France (1780).