The area under review in this report comprises a large territory located in south-western Victoria and south-eastern South Australia. The scope of direct geological information in the areas underlain by marine Tertiary rocks is severely limited, by very poor exposure of the underlying rocks at the surface. Under such conditions, once the scattered exposures have been examined and recorded on the map, little more can be done by surface work; the geologist is thrown back on a study of well and bore records and of the results of geophysical measurements. Considerable literature has been read and records of the principal bores in the area have been examined in detail. It has been recommended that a geophysical survey of the area be conducted, to determine, if possible, any structural features which might exist at depth in this southern-most extension of the Murray River Artesian Basin, which is made up of Tertiary to Recent formations, resting, in the area under review, on a basement of Pre-Cambrian or Jurassic Rocks. This report comprises an overview of the general geology, geological history, stratigraphy and topography of the area under consideration. Geological, bore-hole and well data has been compiled and tabulated. A geological sketch map is included.

This report covers the results of the experimental electrical logging of eight bore holes in the Maitland Coalfields, New South Wales. The theory of the single point resistance and self-potential methods is outlined and the reactions of the coal and other formations are described. The experiments were inconclusive in deciding whether or not electrical logging can be used for correlation. Because there are many vertical and lateral gaps in the stratigraphical sequence of the coal measures it is considered unlikely that electrical logging could be used for correlation in the Maitland Coalfields. However, electrical logging has been recommended for adoption as a routine procedure in the drilling programme to check the recovery of cores in the coal zone. This procedure may results in a saving on drilling costs.

At the request of the Broken Hill Proprietary a geophysical test survey, employing gravity and magnetic methods, was carried out near Wollongong, N.S.W. by geophysicists of the Bureau. The area over which these tests were made is part of the Southern Coalfield of N.S.W. and plans are being made to develop a colliery in it. The subsurface geology is known in part from five drill holes, namely, Nebo No. 2, 5, and 6 and Wongawilli No. 7 and 8. Basalt sills of considerable thickness were encountered in Nebo No. 6 and Wongawilli No. 8. The proximity of sills to the coal seams has resulted, in parts of the Southern Coalfield, in the cindering of the coal, and for this reason it is a matter of considerable importance in planning a colliery to know the area occupied by the sills. The technical aspects of testing, results, and conclusions are discussed in this report.

The beach sands on which investigations were carried out, were mainly from beaches along the eastern coast of Australia and from islands adjacent to this coast. A high percentage of the mineral grains of the heavy mineral fraction in these sands have grain sizes within the range -100 to +200, referred to British Standard Sieves. The grain size of the minerals, combined with the fact that the grains are quite well rounded, makes the heavy mineral sands an ideal subject for separation using the inclined method with the Isodynamic Separator. The use of this method, and the results obtained, are described in this report.

An inspection of radioactive minerals was conducted in the Marble Bar area. The localities of Wodgina, Mount Francisco, Pilgangoora, Alisa Downs, Trig Hill and Cooglegong were visited. Occurrences of monazite, yttrotantalite, pilbarite and radio-active columbite were investigated and samples collected for further examination. An account of the inspection and subsequent findings is given in this report.

This report presents the results of a gravity reconnaissance survey which was carried out under the writer's supervision during the last quarter of 1950. The report describes in some detail the methods adopted in carrying out the field work and the errors to which the results are subject. The results are discussed only briefly and the interpretation given must be regarded as a preliminary one subject to modification as further data are accumulated in extending or otherwise adding to the reconnaissance.

The "Trough" area extends parallel to and 200 to 300 feet west of the eastern beach from approximately 4800 feet north of the zero-line shown on the locality plan, to 6000 feet south of the zero line. A previous report (Record 1948/067) has given an estimate of the quantities of heavy mineral occurring from 2100 feet north to 1100 feet north. The following report deals with the remaining areas. The area was sampled during 8th and 9th September, 1948. Where the heavy minerals were at or close to the surface, samples were obtained from shovel holes. Where the mineral was at some depth below the surface, the samples were obtained from bores put down with a post-hole digger. Estimates of the quantities and grades of heavy mineral concentrates, the quantities of overburden, and the quantities of each of the heavy minerals are tabulated in this report. The data sets from which these estimates are derived are appended.

Widespread use of radio-active tracer elements in medicine, and the increased interest in the search for radio-active minerals, have led to the development of a variety of instruments for the detection of ionising radiations, and their general use by scientists who may have had no training in physics or electronics. While these instruments present a great diversity in appearance, the functioning depends on general principles which apply to all such equipment. The aim of these notes is to present these general principles in a simple form. For details of design, which are often highly complex, and require great skill and experience, reference should be made to the works listed in the bibliography.

A geological field party was engaged in this area from 9th May to 30th September, 1948. This report provides an account of the field operations undertaken throughout this period and describes personnel involvement.

The present report summarises the progress in the study of Cambrian fossils from the Northern Territory and north-west Queensland. The material being studied consists of large collections made in the Barkly Tableland by members of the Bureau of Mineral Resources, and a selected set of fossils borrowed from the Australian Museum. In addition, a comparatively complete collection from the Ord River and Mt. Panton is available for comparison. This report provides an overview of the work being carried out. Brief summaries are provided of the present state of research done by A.A. Opik, and of papers planned by other authors.