14 L rc Sb 25 change with increasing depth. In the 0.60 to 0.66-mev photopeak region of the 0 to l-inch increment, the relatively broad peak is a combination of the 0.60-mev photopeak of spi?5 and the 0.66-mev peak of Cs 137 -B a 137m - In the 1 to 2-inch increment the peak becomes sharper and is oriented toward the 0.66-mev photopeak of Cs 137 -B a 137m . At the 9 to 10-inch incre- ment there is almost complete orientation toward the es 3?_ za?" yeak, with little sb!?> remaining. In Fig. 6 a comparison is given of the spectrum of the 9 to 10-inch increment (Fig. 5) and the gamma spectra of Cs 137 and spt? spikes. Fig. - 7 shows the gamma spectra of increments taken from an undisturbed area in 1958. The first spectrum is from the 0 to 1/4-inch depth and the subsequent spectra are from 1/8-inch depth increments to a depth of l inch. spt? the rare earths, The highest levels of and coo? which move more slowly than e313? or sx?°, are in the 1/2 to 5/8-inch increments, whereas the cst37 which moves most rapidly in this soil type, is in the 3/4 to 7/8-inch increment. Litter and Guano The gamma-ray spectrum of litter, consisting of leaves, twi,s and floral parts splattered with tern droppings, collected from old soil in 1961 (Fig. 8) shows the Cs : much higher than the Sb 125 peak, 13 7 photopeak to be The 1.17 peak of Co 50 is skewed to the left, indicating the presence of the 1.12-mev