The Main Carnic Range as well as the massifs of Julian Alps and Pre-Alps have always aroused a great deal of interest among geologists owing to the presence of a number of stratigraphic successions which are extremely rich in fossils. These sedimentary strata of marine origin ranging from the early Palaeozoic to the late Mesozoic are like the pages of an open book recounting the history of life on earth.
These effects are the result of massive thrusts of the Hercynian and Alpine orogenies, of the African Plate towards the Eurasian Plate, which determined the rise of seabeds in multiple waves over millions of years, until the Eastern Alps range was formed.
That is why around Monte Fleons, near Forni Avoltri, evidence of the earliest life forms can be found, such as bryozoans and trilobites from the Ordovician period (450 million years ago). The massifs of Monte Avanza and Monte Coglians are part of the coral reef of the Devonian (350 million years ago) and are rich in brachiopods, gastropods and crinoids.
In the areas of Monte Dimon and Monte Zoufplan are outcrops of volcanic rocks dating from the Carboniferous, which were generated in submarine environments, the so-called pillow lava (300 million years ago). Further south, the mountain groups of Arvenis-Zoncolan, Cucco-Tersadia, Sernio-Grauzaria and of Amariana, which overhangs Amaro, can be seen; they were formed between the Permian and the Mesozoic (250 million years ago) and features fossils of the most advanced life forms: Cephalopods and Ammonoids.
In the Neozoic period the most superficial deposits of glacial, lacustrine, alluvial or watershed origins were formed which, through alternating glaciations, have led to the current orography of our territory. Those who walk along itineraries from one Alpine farm to the next, paying attention not only to the enchanting scenery of the Alpine landscape, but also to the rocky outcrops that they sometimes stumble across, may train their eyes to discover the infinite world of fossils which, silent and petrified, recount our origins.