The Pilbara gold field area contains many other minerals besides gold. It has long been known that the radio-active minerals, including monazite and certain rare-earth tentalates, occur in portions of the Pilbara field. There is also one known highly radio-active deposit of pilbarite at Wodgina. A survey to determine the position and extent of radio-active occurrences in the Pilbara area was carried out in 1947. In the report on this survey a number of recommendations was made, and subsequently a further field party was sent to the area during the period September - October, 1948. This report is an account of the geophysical work done by this second party. Investigations were carried out at Mount Francisco, Wodgina, Eastern Creek, Pilgangoora, Abydos, Trig Hill, Cooglegong, and Eley's Well. The main part of the work consisted of testing known or suspected rare-earth tantalate deposits. Also, a further search was made for monazite in areas on and near the Cooglegong tin fields. The technical procedure and results of the survey work are discussed in this report.