St. Elias Hill has an interesting geological history that begins at least then million years ago, in the so-called Miocene, a period of the Tertiary era.
There are numerous ancient geological formations outcropping in this area. These formations, consisting of sedimentary rocks (sandstones, marls and limestones) very rich in fossil remains of marine organisms, testify to the fact that in the Miocene the whole territory of Cagliari was affected by prolonged marine ingression. These marine sediments are clearly visible in the Sant’Elia hill and are named in stratigraphic order Arenarie di Pirri, Pietra Cantone, Tramezzario and Pietra Forte.
In Calamosca Hill, between the Fort of Sant’Ignazio and the Calamosca Tower, such geological formations can be observed.
