~35- had been leached out of the top layer of the soil and that the longer-lived radioisotopes were still present. This interpretation could account for the deviation observed in the latter portion of the plot for the decay of mixed fission products. Levels and Decline of Gross Beta Radioactivity at Other Islands of Eniwetok Atoll The amounts of gross beta radioactivity of the land plants collected at other islands of Eniwetok Atoll from March 1954 to April 1956 are given in Appendix Table D; the values for the plants collected from May 1956 to July 1957 are given in Appendix Table E. Before the Nectar detonation the highest amounts were in the leaves of plants collected at Janet Island on April 4, 1954; the average for eight samples was 149 uc/kg of wet tissue, 384 uc/kg. The lowest amounts of radioactivity were found in two coconut meat Island; the range being 8.4 to (30lid endosperm) samples these samples averaged 0.30 uc/kg. from Henry In general the highest levels of radioactivity were found in the plants collected on Janet, Olive and Vera Islands. These levels were significantly higher than those on Belle Island.