The traditional distinction between the Middle and the Upper Palaeolithic is a technical one, the change from flake industries to blade industries. Finding a distinction in more active terms of human behaviour is a rewarding prospect, rather harder to achieve. Here, an attempt is made to find a fundamental distinction in the way groups of humans organized their lives, as recorded in the patterns of scattered stones and bones. The study depends on the meticulous and very detailed records of findspots made by excavation teams led by Jean-Philippe Rigaud, Director of Prehistoric Antiquities for Aquitaine, Bordeaux.