The main sedimentary basins of Western Australia are arranged peripherally to the pre-Cambrian shield which forms the greater part of the state. In 1948, the Commonwealth Bureau of Mineral Resources, Geology and Geophysics, by arrangement with the government of Western Australia, commenced detailed geological reconnaissance of the Fitzroy and North-West Basins. In 1948 and 1949, the R.A.A.F. carried out a programme of aerial photography of these basins and this air-photo survey has since been used as the basis for mapping in the field. In the course of this work several discoveries have been made and as only brief mention of them has been made elsewhere they are included in this summary. The main areas of Palaeozoic sedimentation in Western Australia at present known are the Ord Basin in the far north-east, the Fitzroy Basin, the North-West Basin stretching from Onslow to the Murchison River, and the Irwin-Perth Basin stretching from Geraldton to Busselton.

For the first time the hypostoma of an eodiscid trilobite, Pagetia bootes Walcott, is described. The presence of a doublure with terraced lines, and schizochroal eyes as observed on Australian Pagetiae, is mentioned. Obviously the trilobite nature of the Eodiscidae is no longer in question.

This report gives an overview of the bauxite resources of Tasmania. The report provides a summary of the work, investigation, and sampling conducted between 1941 and 1949. The mode of occurrence and types of bauxite are described. A description, which includes a statement of reserves, is given of each of the eleven individual deposits.

Rock sample from six localities in northern Australia were submitted for macropalaeontological examination. The rock samples and their fossil contents are described in this report.

This report describes the results of a micropalaeontological examination of samples, collected from bores nos. Z.18, T.29, HH.57, and PP.59, in the Moorlands Coalfields.

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.

This report has been written as the result of conversations between the writers and officers of the Joint Coal Board in Sydney, Lithgow and Cessnock, and with similar assistance from the Geological Survey of New South Wales. The writers visited the Western and Northern coalfields during August and inspected most of the operating open-cuts. The results of the enquiries are presented in five tables which are set out at the end of this report and which contain, in statistical form, the greater part of all the information elicited. The text matter of the report is explanatory of the tables and also discusses the methods which have been used in arriving at the estimates of coal reserves. In the ensuing discussion emphasis has been laid on coal reserves available for open-cut mining, and all enquiries directed to the Join Coal Board were concerned with open-cut coal only.

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.

This report contains the results of a brief examination carried out from 1st to 7th October 1950 at Maranboy, Northern Territory, by the writer and Dr. J. Sleis, Geologist, who were assisted by the Inspector of Mines, Mr. W.A. McDonald. The purpose of this examination was to obtain the necessary data for a preliminary assessment of the tinfield based on the ore developed and won to date.

The area investigated, now commonly known as the Daly River Area, is situated on the north-eastern bank of the river, about 35 miles from the river mouth, and approximately 80 miles south of Darwin. The present survey was made in July 1950, in conjunction with work being done by the Bureau at Rum Jungle, and was a general investigation for possible radioactivity in the district. Although no radioactivity of interest was detected, it is considered desirable that the results of the investigation should be recorded. The geology of the area, field work, and results are described in this report.