Monte San Giorgio is an Italian-Swiss transnational site and the area of the UNESCO inscription is of exceptional geo-palaeontological interest due to the presence of numerous fossils from the Middle Triassic (242–230 million years ago) which allow to study the evolution of a large variety of marine and terrestrial fauna. Since the 19th century, excavations have been discovering specimens of rare and unique species, including marine and terrestrial reptiles, fish, invertebrates (bivalves, ammonites, crustaceans, and insects) and plants.
[expand title=”A recognition shared by Italy and Switzerland”]
Monte San Giorgio is a mountain in the western Pre-Alps between Italy and Switzerland that overlooks the southern part of Lake Ceresio or Lake Lugano. The Swiss side was included in the Unesco World Heritage List in 2003 (Mendrisio, Brusino Arsizio), while the Italian side was granted the recognition in 2010. The places included in the UNESCO inscription are in the province of Varese and are related to the municipalities of Porto Ceresio, Besano and Viggiù.[/expand]
[expand title=”An exceptional laboratory of paleontological diversity”]
Monte San Giorgio appears as a pyramid-shaped wooden mountain overlooking the lake with its 1097 m of height. The exceptional value of this naturalistic area is given by the presence of a fossil sequence related to the Middle Triassic (242-230 million years ago). At that time, the area was a sub-tropical environment, a sort of lagoon: an inlet with a depth of a thousand metres, with islets and sandbanks, separated from the open sea by a carbonate reef of calcareous algae. This led to sedimentation phenomena that, associated with a low concentration of oxygen in the seabed, allowed the preservation of the fossil of innumerable organisms, which settled in six superimposed layers. The study of the layers allowed to reconstruct the evolution of many species of marine animals with reference to the changes in environmental conditions and over a period of 12 million years. Moreover, of exceptional interest is the finding of different organisms in the same levels and rocky blocks, because this allows to study the natural association of different forms of life.[/expand]
[expand title=”From industrial exploitation to scientific interest”]
Monte San Giorgio was already famous in the pre-modern period from the 15th century for the cropping out of oily fossil organic material mainly consisting of remains of fish and marine reptiles, used to obtain ichthyol used in pharmacopoeia and cosmetics. The scientific interest in and study of oil shales started in the same period of industrial interventions such as quarries and mines aimed at finding fossil fuel. The first excavations date from the second half of the 19th century; in 1854, naturalist Emilio Cornalia described the finding of some fossil small reptiles, while in 1863 Abbot Antonio Stoppani, considered the father of Italian Geology, carried out the first campaign of paleontological excavations in the area. The long tradition of paleontological studies and orderly management of excavations led to important well documented and catalogued collections of finds used for several scientific publications. The fossil succession of Monte San Giorgio was the main worldwide reference for all future paleontological studies on Triassic marine fauna.[/expand]
[expand title=”The paleontological heritage”]
Monte San Giorgio is part of the tectonic unit of the Southern Alps. Many finds are of rare or even unique species, such as Sangiorgiosaurus or Besanosaurus, whose names refer to the toponyms of the area. 21,000 specimens have been found from the first campaigns to the following excavations in the territory, including 30 species of reptiles, 80 species of fish, approximately 100 species of invertebrates, several microfossils and plants, today on display in the Museo Civico di Storia Naturale in Milan, Paläontologisches Museum-Universität in Zurich, Museum of the Institute of Palaeontology in Zurich, Museo Cantonale di Storia Naturale in Lugano, Museo dei Fossili in Meride, Museo Insubrico di Storia Naturale in Clivio, and Museo Civico dei Fossili in Besano (Italy). Visitor reception for the UNESCO area is granted by the visitor-centers of Clivio (Italy) and Meride (Switzerland).[/expand]