The material submitted for examination came from 35 bores which were drilled in the Adelaide Plains during 1945 and 1946. For comparative purposes, material has also been examined from several bores previously drilled in the area. The bores were sunk for water and the area drilled extended from Bore No. 69 at Royal Park northwest of Adelaide, to Nathan Brewery Bore on the Torrens River. The bores range in depth from 160 to 620 feet. This report comprises descriptions of stratigraphic sequence, fossil fauna, and the structure of the Adelaide Basin, with reference to the material examined. Two accompanying plans are included.

Samples from 46 deposits of the known 76 occurrences of diatomite in Australia have been micropalaeontologically examined, and 27 genera of diatoms represented by 48 species have been identified from them. The distribution of these species in the various diatomites is given in Table II. The following tentative conclusions with regard to the suitability of Australian diatomites for filtration purposes are based on a study of the shapes and sizes of the contained diatoms,' in accordance with English and Californian experience. Extensive deposits of diatomite, which are dominated by the diatom Melosira and which are suitable for purposes other than filtration, are available in Queensland and New South W ales. Nevertheless, this type of diatomite is used successfully by Davis Gelatine (Australia) Ltd., as a filter medium. The commercial value of a diatomite as a filter aid, which depends on the amount necessary to give a perfectly clear filtrate, the speed of filtration, and the character of the press-cake and similar criteria, can only be satisfactorily determined by actual experiment. It is also necessary to establish a correlation between the characters determined by microscopic examination and actual filtration tests before a final conclusion can be stated.

The question of a geophysical survey of the Copperhead mining property at Bullfinch was discussed and it was stated that there was need for a geophysical survey to determine the detailed structure of the jaspilite bodies over a small area concealed by tailings at the eastern end of the jaspilite zone. Following preliminary tests, a detailed survey was conducted in December, 1946. The geology, nature of the problem, and results of the survey are discussed in this report. Two accompanying plans are included.

A geological report on the Alexander, Halley's Comet, and Manolis' Workings mines. The production, grade, geology, mineralisation, ore reserves, and prospecting of the mines are discussed. Accompanying geological plans are included.

A request was made for an estimation of the ore reserves indicated to date in the King Island Scheelite Mine, and for a drilling campaign to be drawn up to prove a total of fifteen years supply of ore at an annual rate of consumption of 200,000 tons. These two matters are dealt with in this report.

Report on surveying, sampling, and plant sampling work carried out during the month of July, 1947.

The Cobar mining field was examined between August, 1946 and June, 1947. Attention was concentrated on the operating mines, viz. New Occidental, New Cobar and Chesney. New Occidental Gold Mines, N.L. owns all three deposits and had requested assistance from the Commonwealth Government to search for new orebodies on their leases. It had previously been recognised that each of these orebodies lay close to a sharp contact between fine-grained and coarse-grained sediments. Of particular interest are the portions of the contact which have been subjected to minor folding, because, immediately to the south of these folds, fracturing favourable for ore localisation has developed. The geological examination was carried out in conjunction with the Geological Survey, Mines Department, New South Wales. Surface and detailed underground mapping were carried out. A preliminary magnetic survey of part of the field was carried out by the Geophysical Section during the first half of 1947. A special study of the New Cobar Mine and the plans of that deposit were made by Dallwitz, Fleischman and Ivanac. This report provides a comprehensive overview of the situation, topography, history, structural geology and general geology of the area. Detailed descriptions are given of the history, workings, orebodies, and structure of each individual deposit. Various accompanying plans of the mines and the Cobar mineral field are included.

The aim of this examination was to map in as much detail as possible the structure of the Apinaipi Anticline, which is situated on the coast of Papua, 100 miles north-west of Port Moresby. The survey programme and the geomorphology, structure, and lithology of the area are discussed in this report. Accompanying maps and section plans are included.

This report comprises notes on access, physiography, the formation of heavy mineral deposits, and the geology of Stradbroke Island.

A geological reconnaissance was made of an area of approximately 27,000 square miles lying north and west of Katherine in the Northern Territory. The report is compiled in two parts. The first concerns general geology and includes accounts of the nomenclature, stratigraphy, structural geology, geological history, and geomorphology of the area. The second part comprises a summary of the economic geology. The mining industry, petroleum prospects, underground water, and recommendations are discussed. A table showing the mineral production figures for the Northern Territory, northern district, is appended.