While walking in the forest, you will see a set of rocks cut like towers.
There are many yellow sandstone benches separated by black marlstone Dated 110 million years ago, this formation gives us an idea of what Provence looked like at that time.
Marlstones and sandstones are sedimentary rocks. Their structure and their arrangement testify to an underwater deposit near a volcanic or metamorphic continent subject to erosion. So you are walking on what must have been a sea in the secondary era.