The most significant natural areas in the park include a number of badland basins located along the clay soils that stretch from the Samoggia Stream to the Panaro River: the narrow valley of the San Teodoro gorge, the valley head of the Ramato Stream, the stunning Pan Perso amphitheater. The outcrops in these deep incisions are the oldest rocks in the Bolognese Apennines, as they were so thoroughly described by the Bolognese geologist Bianconi in a study in 1840: "The rock surface is extremely polished, gentle, creamy to the touch, lustrous, waxy or metal-like, depending on the scaly components that constitute this type of Clay (…) and it is because of this very unique feature (…) that we believe these rocks should be temporarily referred to as "Argille scagliose" (scaly clays)…".
The Argille scagliose scaly clays
Ancient rocks created from the accumulation of sediment in the deep sea beds in and around an ancient oceanic basin that geologists call the Ligurian-Piedmont Ocean.
These rocks comprise a number of interesting minerals: pyrites, marcasites, barytes (the local badlands are especially rich in this mineral), calcites and septariums (particularly at Pan Perso).