TABLE OF CONTENTS Page INTRODUCTION METHODS OF COLLECTION AND MEASUREMENT RESULTS AND DISCUSSION Depth Gradient of Gamma Spectra Old Soil Litter and Guano Young Soil Depth Gradient of sr?° Young Soil 25 25 Undisturbed 25 Eroded 25 Old Soil 28 Horizontal Movement 28 Buried Organic Layers” 30 Roots 30 Pumice 31 CONCLUSIONS 33 SUMMARY 35 REFERENCES 37 ™MY RADIOAUTOGRAPHS