A refleotion traverse was shot across the centre part of the Giralia Anticline in the Carnarvon Basin of Western Australia, in an attempt to verify the unconformity between Mesozoic and Palaeozoic sediments shown by a previous traverse across the northern part of the anticline. Shallow seismic events recorded were of good quality and correlated very well with surface geology. They also indicated two faults in places where steep dips in surface beds might, by anaJogy with the northern end, be expected. Deep events were in general of poor quality and inconsistent. However, over approximately a mile of the traverse, they were of good quality and indicated nonconformity with the shallow events.

The seismic survey made by the Geophysical Section of the Bureau of Mineral Resources to assist in the search for oil in the Carnarvon (North-West) Basin of Western Australia. The seismic field work in the Carnarvon Basin was confined to one field season, i.e., from April to December 1951, and consisted of surveys on the Capa Range and Giralia Anticlines. Both refraction and reflection methods were used. The purpose of the seismic work was to determine if the structures at surface extended to depth and thus establish if a suitable site for a deep exploration drill hole exist. The seismic work has shown that seismic methods are applicable in the investigation of possible oil-bearing struotures in the Carnarvon Basin. It is clear from the results obtained on the Giralia Anticline, that investigation with a view to tile selection ot deep drilling sites cannot be carried out thoroughly without seismic surveys of selected areas.

This quarter, with its favourable climatic conditions, has seen the greatest activity in the field for the year. Thirteen geologists and five geophysicists, together with many assistants, have operated in the area on many prospects. The Darwin office and laboratory are well-established and providing many services to the public such as assaying, instrument repair, and geological and geophysical advice. Detailed geological and geophysical work has been commenced or continued at the following prospects: A.B.C., Edith River, Burrundie, Brock's Creek and Adelaide River, while minor investigations have been carried out at many other localities. Three drills have operated throughout the quarter. Regional geological mapping has been continued over a wide area. The amount of work being done will decrease during the coming quarter due to the approach of the "wet" season.

During the 1953 field season geochemical prospecting techniques were employed as an additional tool in the search for ore deposits in the Northern Territory. Areas of particular interest were those at which radio-active minerals had already been discovered or at which radiometric anomalies were being investigated. The work thus included the already proved Rum Jungle field as well as the new prospects at Brodribb, Waterhouse, Edith River, and Coronation Hill. A direct chemical test for uranium in soils was not used, the discovery of the radio-active areas being left to the sensitive ratemeters now in use. The close association between copper and uranium was used to advantage as it is present at many of the uranium prospects in the Northern Territory. It is a logical step to use the geochemical techniques to locate new copper mineralization, and then to carry investigations further by attempting to locate uranium in the vicinity of the copper, particularly in areas covered by deep soils where ratemeters are of no use. A field test for cobalt, a metal often closely associated with both copper and uranium, was developed, but of the many samples tested for this element only one gave a positive test. It is possible that the cobalt, an element which is extremely mobile in the oxidized zone, has been completely leached and dispersed from the radio-active minerals.

Geophysical surveys of the magnetite deposits of Australian Magnetite Pty. Ltd. at Gulgong were made by the Bureau in 1952 and 1953, and revealed that the Tallawang deposit was the most important one. The present report gives the results of a detailed magnetic survey which was made over this deposit in August, 1953. Results show that three concentrations of very strongly magnetic material exist within the Tallawang deposit. The southern concentration is unlikely to contain considerable reserves beyond those in sight. The central concentration has been partly worked and could yield reserves of ore from the west wall of the quarry. The northern concentration, which has not been worked, could yield limited reserves. It is shown that the deposit, as a whole, pitches northwards. Some exploratory drilling is recommended on each of the three concentrations.

In connection with the use of airborne equipment for the detection of deposits of radio-active minerals, the Bureau has successfully used a DC.3 aircraft for the rapid coverage of large areas. It has been frequently suggested that a helicopter would have the following advantages over a conventional aircraft: (i) It can fly safely at lower heights and slower speeds than an ordinary aircraft, thus obtaining greater sensitivity from the detecting apparatus; (ii) It can be used effectively and safely in mountainous areas, in which low flying by a conventional aircraft would be impossible; (iii) It would enable the observer to locate exactly and identify from the air any small area on the ground showing radio-activity. In order to assess the performance of helicopters, a programme of test helicopter-mounted equipment over selected areas in New South Wales was carried out during March, 1953. The areas selected were: (i) Carcoar. This is a hilly area, but not timbered; (ii) Wunglebung, near Tenterfield. This is a mountainous, heavily timbered area; (iii) Broken Hill. This is a relatively flat featureless area; (iv) A test run was also made over Plen's deposit at Toongi, near Dubbo, in order to obtain and check on the sensitivity of the detecting instrument. The survey techniques used and the results obtained in the several areas are discussed in detail below.

Report on the activities of the administrative and technical sections in the Katherine-Darwin area, to May, 1954. A brief account is given of geophysical operations. The results of prospecting and development work are summarised.

This report covers the work done by the author who was geophysicist with the Australian National Antarctic Research Expedition at Macquarie Island from April to December, 1953. It is a sequel to Records 1953/30 and 1954/32 and deals with observatory routine and maintenance and other general duties required of the geophysicist. The report contains the results of absolute magnetic observations and initial earthquake phases. Detailed tables of scientific results will be published separately in reports at present in preparation.

Mr. H. B. Owen forwarded specimens collected by Dr. G. Sleis from "somewhere near the base of the Buldiva Group about 50 or 60 miles north-east from Katherine", Northern Territory for palaeontological examination.

The earliest recorded geological work on the area covered by the Minilya four-mile sheet was that of Woodward (1907) who examined the country north of the Minilya River and noted the limestone on the west flank of the Giralia anticline. In 1909 A. Gibb Maitland described the Carboniferous and Permian succession in the area drained by the Gascoyne, Lyons, Minilya and Lyndon Rivers, but referred the whole sequence to the Carboniferous. Geologists of Oil Search Ltd., under D. Dale Condit, examined the Carnarvon Basin in 1932, 1934 and 1935. Raggatt (1936) described the stratigraphy of the Permian in some detail and subdivided the Cretaceous sequence. Raggatt and Fletcher (1937) examined the fauna of the Permian of the Carnarvon Basin. Teichert did detailed stratigraphic work in the Wandagee area from 1938 to 1940. Geologists of the Bureau of Mineral Resources mapped the Minilya Sheet from 1948 to 1951, using R.A.A.F. aerial photographs. The present sheet is entirely the result of the mapping of the Bureau geologists although much of the stratigraphic nomenclature is adapted from Raggatt's and Teichert's work.