At the end of the 1949 field season A.A. Opik, accompanied by D.M. Traves, collected fossils and made stratigraphical observations in the area between the lower reaches of the Ord River and the Victoria River. This report gives a preliminary summary of the results of the journey.

This report comprises descriptions of certain rocks collected by Dr. H.G. Raggatt in the Torquay - Airey's Inlet area, Victoria. The rocks are isolated specimens and no general conclusions applicable to the group as a whole have been drawn.

Seven samples were collected from the 16-mile Government bore, 16 miles west of Alice Springs, and forwarded for examination. This report gives a detailed description of these samples.

During the period 10th October to 15th November 1950, the writer visited the Rum Jungle area in order to direct the local and regional geological mapping, with a view to establishing the geological relationship between the various prospects, the manner of occurrence of the ore bodies, and if possible the control of mineralisation. Owing to the short time available for the field work, the present report must be regarded as a critical preliminary study of the area to aid future planning, rather than a complete investigation. Only the broader aspects of mineralisation are dealt with in this report.

The areas included in the geophysical survey, namely the Laloki, Moresby-King and Dubuna leases, are among those held by Mandated Alluvials N.L., and lie in the Astrolabe Mineral Field. The positions of the leases held by the Company are shown in Plate G73-1. Laloki, the main producer of copper, is situated 20 miles by road from Port Moresby, near the junction of Sapphire Creek with the Laloki River. The Bureau was requested by Mandated Alluvials to carry out a geophysical survey in the vicinity of the known deposits and in adjacent areas. Both Laloki and Moresby-King mines has been in production up to the time when the war in New Guinea caused a suspension of operations. During the war the mine workings and much of the plant were completely destroyed. When consideration was given to the best method of reopening the mines it was decided that, if a large enough tonnage or ore could be proved sufficiently close to the surface, it would be most profitable to continue open-cut mining, and possibly install a flotation concentrator to avoid the troubles that had always accompanied smelting. The aim of the geophysical survey was, therefore, to locate a body of ore large enough to justify the adoption of these mining and treatment methods.

The samples described in this report, which were submitted by the Director for petrographical examination, come from the Janjukian and Anglesean deposits between Torquay and Airey's Inlet. All sedimentary rocks from the area have been named according to the classification drawn up by M.A. Condon. The results of a rough chemical analysis made in 1947 on a sample of supposed jarosite are given, and a note on the occurrence and possible origin of the glauconite found in many of the samples is appended.

Previous investigators in the area have interpreted the Nerrima Dome as a dome closed by folding (Wade, 1936), a dome closed against a transverse fault at the eastern end (Kraus, 1942), and as a westward plunging anticlinal fold probably closed by transverse faulting (Reeves, 1949). The purpose of the present survey is to determine by detailed geological mapping the true structure of the Nerrima Dome.

The primary aim of the investigation was to determine the reserves and distribution of monazite in the deposits of heavy mineral sands along the East Coast. These deposits contain most of the known world reserves of zircon and rutile for which they are being exploited at various localities, mainly from North Stradbroke Island in Queensland to Ballina in New South Wales. Monazite forms little more than 0.5 per cent of the mixed concentrates, but can be recovered as a by-product from the separation of the other minerals. The monazite forms a source of supply of cerium and also of thorium. The thorium content of the monazite is determined on the basis of its radioactivity. This report gives an account of the field and laboratory work carried out. The results of the laboratory work, which included the separation and examination of minerals, the radiometric determination of quantities of monazite, and the investigation of the thoria content of monazite, are described in this report.

Following a report by Mr. McDougall of the existence of sulphur deposits, possibly of large dimensions, on New Britain, deposits at Lolobau, Pangalu and Kasolali were examined in the early part of June, 1950, by the Chief Geologist, accompanied by A.K.M. Edwards, Senior Geologist, Port Moresby and G.A. Taylor, Vulcanologist, Rabaul. This report gives an account of the examination and its findings.

Geophysical work commenced at the beginning of September 1949, and was completed in December. Of this period, ten weeks were spent at Hermidale and five weeks at Girilambone. The operations comprised both geomagnetic and self-potential surveys. The geology, history, and the results of the work for the areas surveyed, are described in this report.