2 ar NM OO IREomeee itAOtah*natal Local differences in dose rates at one inch Survey meter readings were also taken at one inch above the ground with the beta shield both open and closed. There was no apparent correlation between these readings and the gamma dose rate readings at three feet, except in a very general way, but such readings were useful in selecting areas from which to sample and indicated local distribution of the activity. For example, when measurements were made one inch over the ground with the shield open in 1959, the levels were higher after the litter was removed from the soil and there were markedly higher levels of activity over areas covered with soil algae than over bare sand. Attempts also were made with a survey meter to determine local differences in activity in trec+. This was unsuccessful, since the general levels of activity masked local effects within the trees, even though laboratory analyses showed that the activity in lichens and mosses collected from the bark was several times higher than in the bare portions of the trees. The use of survey meters to determine the vertical distribution of activity in soil pits was impracticable due to the high background levels from surrounding contamination and the fact that the bulk of the radioactivity was in the surface inch or less of soil.