Mt. Gallo is a carbonate relief which formed from the Mesozoic (225 million years ago) to the Middle Eocene (54 and 33.7 million years ago). It is a karstic mountain presenting several superficial and endogenic erosive features and several cavities: Fossa del Gallo, Grotta Perciata, Grotta dei Caprari, Grotta delle Vitelle, Grotta Regina, and Grotta Caramula.
Further information (Italian text)
Thanks to the presence of ideal conditions, a bed of Posidonia oceanica grows offshore, on the sandy seabed, while in Secca della Barra there is a coralligenous community reaching the 70 meters of depth.
Further information (Italian text)
The rocky coast is bordered by the vermetid "trottoir" (or 'rim'). This consists of dense aggregations of vermetid gastropods living inside calcareous shells cemented to the nearby organisms; since they lie on the surface of the water, they form a sort of living side-walk (called "trottoir"): the vermetid trottoir is endemic of the Mediterranean and only lives where the quality of the sea is high.
Further information (Italian text)