1. Cox et al., Nature, 190, 40 (1960).
2. Dixey, F., “Vertical Tectonics in the East African Rift Zone”, Rep. Twentieth Intern. Geol. Cong. Mexico (1956).
3. Holmes, A., and Cahen, L., Acad. Royale des Sciences Coloniales, Nouv. Sér., 5, fasc. 1, 102 (1957).
4. Macgregor, A. M., “Pre-Cambrian Formations of Tropical Southern Africa”, Rep. Nineteenth Intern. Geol. Cong. Algeria (1953).
5. Mennell, F. P., Trans. Geol. Soc. South Africa, 22, 68 (1920).