long process of mountain chain formation that created the super-continent Pangea, at the end of the Paleozoic (359 Ma). This orogeny is responsible for the emergence, fracture and folding of the shales, greywackes and quartzites in the Foz Côa region. Erosion processes subsequently have eroded this mountain chain. Some wrinkled rocks and relieves in resistant rocks, still present today in all continents, are the only testimonies. In the Foz Côa region, they are represented, by the quartzites of the Mount Saint Gabriel.