THE Walvis Ridge is one of the most conspicuous features of the South Atlantic. It extends from near Tristan da Cunha on the Mid-Atlantic Ridge to the African continental margin and has three main segments. The western segment is oriented SW-NE, the central one N-S and the eastern one SSW-NNE. The Walvis Ridge may have kept pace with the opening of the South Atlantic which started in the Early Cretaceous1-6, either by transform fault mechanisms7-8 or by a mantle hot spot and plume 9-12. The eastern segment is thought to have been built throughout the Middle Cretaceous, that is, between 120 m.y. ago and 80 m.y. ago13-15. We report information obtained from an investigation of the age and depositional conditions of sedimentary rock recovered during the Walda cruise of the RV Jean Charcot (April-August 1971). [NOT CONTROLLED OCR]