The Stretta di Fleons is a deep gorge carved by the turbulent waters of the Degano torrent as it runs between the eastern slope of Monte Navastolt and the western one of Navagiust. This too, like the gorge on the Rio Bordaglia, is set within the metamorphosed marbles derived from massive Devonian limestones, although here the incision made by the stream is deeper. In addition to the erosion pots and smooth rocks there are some jumps and small waterfalls.