In Minceto, near to the little chapel at the junction for Mt. Reale, a path leading to the "Rocche del Reopasso" leaves and then it goes down to Crocefieschi. The rocky slopes of the "Rocche del Reopasso", made of the large outcrop of "Savignone conglomerate", culminate in the summits of Carrega del Diavolo (959m) and of Biurca (940m). The rocks have a calcareous-marly composition, rarely a volcanic one. A system of faults and fissures linked to geological phenomena dating back to the Quaternary is the main cause of the presence of steep, sometimes overhanging slopes.