The cliffs and the old hoppers (large funnels) bordering the creek of Port-Miou are the remains of the former Solvay quarry that exploited the local Urgonian limestone (calcium carbonate) for the manufacture of lime between 1900 and 1981. The limestone was extracted with dynamite and then crushed on-site to allow its transport by boat to the Salins-de-Giraud plant where it was added the sodium chloride produced in the salt works. Unlike the other quarries of Cassis, the quarry of Port-Miou has never been exploited for freestone.