Detailed ground checking of radiometric anomalies recovered from a semi-regional aerial geophysical survey flown in August 1969 over the Plumbago area, plotted down to a scale of 1:25,000, did not disclose any significant radioactive mineral deposits with a large surface expression. Some very small areas of exposed mineralisation (mainly secondary uranophane staining, and possible fine-grained allanite or orthite), and also of probable near-surface mineralisation, were found by outcrop inspection and scintillometer profiling. Mineralogical and petrological studies of rock samples taken from the former suggest that U, together with Ti, P and rare earths have likely been introduced to the sheared basement by late-stage Mg- and possible Na-metasomatism.