By digging under the city of Le Mans, is revealed an old seabed dating from a hundred million years ago. This period bears the name of «Cénomanien» in homage to the old name of the city. The rocks of that time were first described here. In these old rocks, contemporary dinosaurs, are imprisoned fossils of the oyster family, octopus and others. Come and discover them at the Green Museum, touch them, classify them, observe them under a microscope.