na ne ~— amen, TABLE OF CONTENTS INTRODUCTION Page METHODS OF COLLECTION AN D MEASUREMENT RESULTS AND DISCUSSION Depth Gradient of Gamma Spe ctra - Old Soil Litter and Guano Young Soil Depth Gradient of sr2? RADIOAUTOGRAPHS Young Soil Undisturbea Eroded Old Soil Horizontal Movement Buried Organic Layers Roots Pumice CONCLUSIONS SUMMARY REFERENCES 12 12 14 18 21 25. 25 25 25 28 28 30 30 31 33 35 37