The petroglyphs (rock engravings), located on stone outcrops within the valley, were first identified by British amateur archaeologist Clarence Bicknell in 1881. Between 1897 and 1902, Bicknell copied and catalogued more than 10,000 drawings.
Beginning in 1967, an extensive study of the petroglyphs was begun by French archaeologist Henry de Lumley. De Lumley and a team of his postgraduate students classified the petroglyphs in the 40 km2 area, with the greatest concentration in a 14 km2 archaeological site on the slope of Mount Bégo. the engravings display objects like daggers, axes, and scythes. Suns, stars and spirals are represented. Ovals with criss-crossed lines may represent land or the earth. Some anthropomorphic figures have been found. The most common drawings are of horned animals.[2]
Henry de Lumley has theorized the petroglyphs are the work of a Mediterranean Bronze Age people who worshipped the bull and for whom Mount Bégo was a sacred site.[3]