These are ancient ocean beds dating back some 180 million years. A truly hostile rock for plants, arid, lacking in calcium and rich in heavy metals, but for this very reason it is home to very important habitats with sparse shrub vegetation called garrigue, with herbaceous species that live exclusively in contact with these rocks and extraordinary spring blooms. These are ancient ocean beds dating back some 180 million years. A truly hostile rock for plants, arid, lacking in calcium and rich in heavy metals, but for this very reason it is home to very important habitats with sparse shrub vegetation called garrigue, with herbaceous species that live exclusively in contact with these rocks and extraordinary spring blooms.