The Stonebarrow cliffs are of Jurassic age, becoming geologically younger further east (the rocks of Golden Cap are early Cretaceous). The bottom of Stonebarrow is home to the Black Ven Marls a layer of rocks similar to those of Black Ven. Slightly higher are the Belemnite Marls, where a number of belemnites can be found. Slightly higher up is the Green Ammonite beds, where fossils of a species of ammonite exist. Higher still are Eype Clay, Upper Greensand and younger Cretaceous rocks.