The Arrifes section, also referred to as Arrifão, is made up of carbonate rocks from the Lower Cretaceous (145 – 101 Ma) that can be observed on the cliff in subvertical to vertical strata, as if they were books on a shelf, giving rise to the popular designation of "bookstore". These were deformed during the tectonic inversion of the Algarve Basin, which caused compression and uplift of the Albufeira diapir. The vertical strata emerge between Praia dos Arrifes and Ponta da Baleeira in a long sequence of 194 m formed by interspersed fossiliferous limestones, variegated marls and muds, and small sandstones and conglomerates.

On the vertical layers of the Lower Cretaceous, horizontal fossiliferous limestones from the Miocene (23 – 5.3 Ma) can be observed, deposited above in unconformity, both sequences being affected by post-Miocene karstification processes. These deposits, formed in both marine and continental environments, represent a paleontological heritage of international relevance given their diverse and unique fossil record, which highlights centimetric foraminifers of Orbitulina (Mesorbitolina) parva and traces of footprints of the titans that inhabited our territory, dinosaurs gigantic creatures with long necks and small heads, the so-called sauropods.