Around 9500 BC, a number of changes take place in the life ways of human groups that, henceforth, will be designated as Mesolithic. These changes set them apart, behaviourally, from the preceding periods. Even though the ancestral know-how was passed across the Pleistocene/Holocene boundary, new solutions were implemented. Groups became more mobile and more dependent on the exploitation of marine resources. Shell middens crop up not just all along the Atlantic faCade but also in more interiorly located sites. Technical choice and mode of resource extraction are situationally adapted and/or...