During the follow-up work of Ribeiradio hydroelectric venture several archaeological findings were made, most notably traces of human set tlement from the Paleolithic. These communities were fixed in estuaries along the Vouga, as evidenced by the findings at the mouth of Teixeira river, at the mouth of Gaia stream, and at the mouth of the Pontinha brook. So far this type of occupation was unknown on this area, constituting an exceptional case in the Iberian Upper Paleolithic, and the only one in the northwest of Portugal. One of the best deposits is located at the mouth of the Teixeira river (at Rôdo), and has traces of combustion structures, cabin funds and characteristic stone artifacts from the Upper Paleolithic. The excellence of these findings is demon strated by the presence of all whittle phases of the lithic industry: cores, chips, whittle scraps, splinters, plates and scrapers, some of them on display at the Municipal Museum of Sever do Vouga. These findings are attributed to Magdalenian period, between 17,000 and 10,000 B.C., and testify the ancestry of human occupation of these sites.