 There is some counterclockwise rotation of Italy; hence the faults in the Tyrrhenian Sea slip both parallel to the shoreline and perpendicular to it.The surface rock in the Anti-Apennines was deposited on the floor of Tethys Sea during the Jurassic and Cretaceous of the Mesozoic.This lighter calcareous rock rides over the front of the subduction zone, uplifted by compressional and isostatic forces.