Looking for the traces of the last hunter-gatherers: Geophysical survey in the Mesolithic shell middens of the Sado valley (southern Portugal)

This paper presents the results of an application of geophysical surveying methods to Mesolithic sites in Portugal. Magnetic gradiometry maps have been produced at the sites of Vale de Romeiras and Poças de São Bento. At the latter, three excavation seasons have provided information to test the results of the survey. It is concluded that these techniques can be considered efficient tools for the delimitation of the sites and for the identification of Mesolithic and Neolithic structures.