“…Early studies identified this large surface as an erosive relict of karstic origin developed from the Tortonian to the Pliocene (Lhénaff, 1967(Lhénaff, , 1981Martín-Serrano, 1986). These authors identified a late Tortonian planation event in the zone, but suggest a generic late Pliocene "Villafranchian" age (c. 3 to 2 Ma) for the eventual development of the erosion surface.…”