The park territory is located between the Cimino-Vicano volcanic district to the north-east, formed during the Pleistocene (starting around 1.64 million years ago), and the reliefs of the Tolfa mountains to the south-west. On a calcareous substrate of sedimentary origin, of Meso-Cenozoic origin, benches of reddish tuff with typical dark scoria rest: it is the so-called red tuff with black scoria, in which the deepening of the hydrographic network formed by the Biedano, Vesca streams and their tributaries produced the formation of high escarpments.