Results of extensive paleontologic, stratigraphic, and petrologic investigations of the schistes lustres of Corsica indicate that they are not Mesozoic or Tertiary but much older, possibly Paleozoic. The metamorphism which affected the schistes lustres is pre-Mesozoic as indicated by the fact that Hercynian granites overlie and granitize the schistes lustres. Further support is provided in that the Eocene, Jurassic, Triassic and Permian strata contain pebbles of rock originating from them. The Corsican schistes lustres may be compared with the Chataigneraie schists of Cantal or the Cevennes schists.