34 radionuclides in old soils is as follows, in order of greatest penetration: est37, sr?°, spt?5 | co°®, zn°>, or 44 py 144 Eut?> and probably other rare earths. In the young soils, consisting almost entirely of parent material, the positions of cs*3? and spt?5 are reversed and the other radionuclides appear to be more completely retained in the surface algal crust. The maxi- mum concentration of fallout radionuclides remains at the soil surface, a few inches or less in depth, except in areas where there has been erosion. In the eroded areas large particles containing both soil algae and radionuclides are randomly distributed to a depth of a few inches. There is some horizontal movement of radionuclides but such movement appears to be very localized and thus is of little consequence in the overall picture of distribution. @st37 and sr?° are the principal radionuclides entering a cycle within the soil-plant system. Any loss from this system appears to be small (a fraction of one per cent per year), but a definite conclusion can not be drawn from the data.