1. Park, K., Pattullo, J., and Wyatt, B., Limnol. Oceanog., 7, 435 (1962).
2. Seymour, Allyn, Laboratory of Radiation Biology, University of Washington, Seattle (personal communication, 1963).
3. Osterberg, C., Cutshall, N., and Jennings, D. (in preparation).
4. Osterlberg, C., Ph.D. thesis, Department of Oceanography, Oregon State University, Corvallis (1963).
5. Krauskopf, K. B., Geochim. Cosmochim. Acta, 9 (1956).