The valleys of the Bosso and Burano rivers represent two of the most beautiful examples of rock gorges in the province of Pesaro and Urbino, although both born in the Umbrian territory.
Bosso, a tributary of Burano, flows between the Nerone and Petrano mountains belonging to the anticline (convex rocky fold) that from Nero to the north west reaches Mount Catria to the south east.
Burano river, which forms its gorge just south of the previous one, flows between Mount Petrano and Mount Tenetra, first passing through the town of Cantiano and then that of Cagli where it receives the waters of the Bosso river.
These two gorges represent excellences from a naturalistic point of view, in particular as regards the geology of this part of the central Apennines. In the rocky stratifications cut by these two rivers it is possible to "read" the geomorphological history of this area of Italy that stretches back in time from about 200 million years ago to today! Fossil remains of marine organisms extinct 66 million years ago, the Ammonites, are found in the outcropping rocks.
It is possible to organize excursions by contacting the local Hiking Guides. Escursionistiche.
(text by Cristiano Ceccucci)
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