A provisional Isogonic Map of Australia and New Guinea for the epoch 1950.5 has been prepared by revising the observational material used in the Isogonic Map for 1942.5, and including observations made at various parts of Australia since 1942. The extensions of the Isogonic Lines beyond the coast line of Australia depend almost entirely on extrapolation from the earlier work.

At the invitation of Prof. S.W. Carey, the author visited Tasmania during the period 15th November to 2nd December, 1950, to take part in discussions on Cambrian geology in Tasmania and to learn in the field the results of recent investigations on Tasmanian older Palaeozoic rocks. During the visit the author had the opportunity of expressing his opinions both on newly discovered fossils and on the age of some Palaeozoic units, and the main object of this report is to record these opinions.

The Palaeozoic rocks of the Bonaparte Basin outcrop at the head and along the western side of Joseph Bonaparte Gulf and extend across the border between Western Australia and the Northern Territory. The Bonaparte Basin is the least known Palaeozoic basin in Australia, due partly to the remoteness of the area and the discouraging results of early coal explorations, and partly to the fact that the stratigraphical extent of the Palaeozoic sequence was only discovered in the last ten years. The Palaeozoic sequence so far established includes Cambrian, Ordovician, Devonian, Carboniferous and Permian sediments which rest on a pre-Cambrian basement and which are overlain in places by a mantle of Lower Cretaceous sediments. The authors intend in this paper to give an account of Carboniferous and Permian sediments of the Basin, as far as present knowledge permits, with briefer mention of the Lower Palaeozoic and Mesozoic sediments of the area.

A sample of lignite from a new water bore on the Freud River was sent for micropalaeontological examination. The results of the examination are described in this report.

Mount Hope, a small town in Central New South Wales, is south of and 101 miles by main road from Cobar, and 11 miles north of Matakana siding on the Sydney-Broken Hill railway line. The ores mined in the Mount Hope district have been mainly those of copper, the principal mines being the Mount Hope mine, close to the town, and the Great Central and Comet mines, three miles further south. At present, the only mine in production is the Mount Hope mine, where the leaching process is being used by the Caroline Copper Mines. At the request of North Broken Hill Ltd., geophysical surveys were carried out on two areas: the Mount Hope mine area, and the Comet Mine area. The field work was commenced in May, 1950, and occupied three months. This report gives an account of the geophysical surveys and their results.

A micropalaeontological examination was conducted on a sample of diatomite from Redesdale. The results of this examination are described here.

This map has been prepared to display the probable form of the Isogonic Lines in the regions surrounding Australia, the boundaries being the meridians 85°E and 180°, and the parallels of latitude 10°N and 60°S. This report contains explanatory notes to the isogonic map.

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This report is comprised of nine separate sub-reports, referred to as records nos. 1951/3a to 1951/3i. Micropalaeontological examinations were conducted on samples from various localities in the region of Mt. Gambier, South Australia. The results of these examinations, together with any accompanying notes, are recorded in the respective reports.

Nine samples of clays from Western Australia were received from R.S. Matheson for micropalaeontological examination. No microfossils were found in these clays. A description of these samples is given in this report.