The route shows three basaltic outcrops: Molí Fondo, Boscarró and Fontfreda scarps, visible due to the erosive action of the river Fluvià and the creek of Bianya. From Molí Fondo you can see three overlapping lava flows. The first comes from the volcanoes of Batet de la Serra and date, approximately, about 600,000 years. The second can be traced back to approximately 150,000 years. The third youngest corresponds to the quarry Boscarró and came Garrinada volcano in Olot, and has an age of about 120,000 years. In the area of Boscarró can also see the remains of the Iberian village.