Parco Naturale Regionale del Beigua

The rocks in the area of Arenzano are an example of Beigua Park's high geodiversity, as they are completely different from the ones described so far. They are called "crystalline rocks", composed of silica-rich minerals, and are very ancient (280 million years); they once formed an ancient continent. The Promontory of Arenzano is roughly shaped like a frustum of a pyramid with a wide sandy and pebbly marine terrace on the top. Faults circumscribe the elevation; the northern fault is the border of a Pliocene graben.