Up to the start of the CAI path 408 you are walking on an alluvial fan that has been forming for 5000 years. It consists of materials eroded from Monte di Rivo and then transported and deposited by the Rio Randice in the area where it flows into the Bût torrent, above what remained of the ancient accumulation of the Monte di Rivo and Cucco landslide. Its development has brought about the displacement of the course of the Bût towards the slopes of Monte Dauda, ​​causing erosion phenomena on the right bank close to the bridge for Noiariis and at the locality of Araseit (a Geosite). This has exposed the passage between the Bellerophon Fm. (from the Permian) and the Werfen Fm. of the Triassic, that is to say, the transition from the Palaeozoic to the Mesozoic.