Gypsum karst has been studied in Italy since the last decades of the l9th Century. In 1917 the geographer Olinto Marinelli published “Fenomeni carsici delle regioni gessose d’Italia”, a fundamental synthesis of the early research. He distinguished 56 different morpho-karstic gypsum units and/or areas, which are all different in size and character, and described them, paying special attention to their surface morphology and hydrology. Marinelli listed all the main gypsum units and only a few secondary outcrops were overlooked. After Marinelli’s synthesis, except for some discussion of archaeological caves, only a few papers about gypsum karst and environment were published until the nineteen-fifties. In the nineteen-sixties and seventies muc...