From a geological point of view, the islands of Hyères belong to the Maures Massif, a bedrock metamorphosed during the Hercynian orogeny. The observation of the coast of Port-Cros (on the right) reveals the deformations undergone by the rocks, mainly mica schists. Their schistosity plane and the axis of their folds are oriented north-south over the entire surface of the island. Such characteristics testify to at least two successive tectonic events that developed and then folded the schistosity.