wonscheeebee 14 spt25 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 spt?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 est37_ Bat?7™ peak, with little spt25 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 cst37 and spies 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 1 inch. spi?5, the rare earths, cst3? or sr??, The highest levels of and co°?, which move more slowly than are in the 1/2 to 5/8-inch increments, whereas the est37 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, twigs and floral parts splattered with tern droppings, collected from old soil in 1961 (Fig. 8) shows the cs??? photopeak to be . 125 much higher than the Sb peak. The 1.17 peak of Co 60 is skewed to the left, indicating the presence of the 1.12-mev