
A calan is a hard limestone cliffs that formed between 160 and 90 million years BC. These cliffs are the vestiges of an oceanic presence. Indeed, the Thétys Ocean was here during the Jurassic period, the same period that saw the water level decrease. It was then that massifs, like the crests of the Alpilles, or like the calans, were formed. The most famous are the Calan de Rousset, the Petit Calan and the Gros Calan.