Where does the limestone come from?

Limestone is a sedimentary rock formed by the build-up of shells and remains of marine wildlife. Remains are being slowly accumulated and transformed into rock by the sheer force of temperature and pressure.
Around 130 to 120 million years ago, the Roc de Chère was under the sea. Fossils, the remains of the limestone shells of numerous organisms appeared on the seabed at this time. The soil of the Roc de Chère at that point was made up of limestone from the Urgonian period, rich in fossils.
Further on, as shown in the photo, limestone with small nummulites can be seen, indicating that it was formed at different epochs.
In everyday life, limestone can be found in many different forms: chalk on blackboards, snail shells, etc.