F.M. Phillips, M. Flinsch, D. Elmore, P. Sharma

Antiquity 71 (1997) 100-104

The Coa valley petroglyphs in Portugal have a style indicative of a Palaeolithic age. These engravings have become controversial because they were in danger of being flooded by a proposed dam, and because radiocarbon dating results suggest that they are Holocene in age.