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A number of fossils were sent in for examination by the Director of Mines, Tasmania. The results of the examination are recorded in this report. Two different horizons are represented.

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.

Attention has been directed to the cobalt workings at Carcoar as a possible source of radioactive minerals in two ways. During testing of museum specimens for radioactivity, it was found that cobalt ore from Carcoar was strongly radioactive. Also, the occurrence of uranium in the cobalt ores was reported by Mr. McKillop, formerly a land holder in the area, who submitted a copy of a report signed by Professor T.H. Laby, certifying the presence of uranium in samples examined by him, and at a later date, a sample containing an uranium mineral. A brief visit was paid to the area in 1948, and the presence of strong radioactivity on dumps was confirmed. A more extensive survey of the area was, therefore, undertaken by geophysicists during 1949-50 and 1950-51. This report gives an account of the geophysical operations carried out in the vicinity of the Carcoar cobalt workings and describes the results of these investigations.

The geophysical survey described in this report was undertaken at the request of the Snowy Mountains Authority for the purpose of investigating possible sites for the proposed Spencer's Creek dam. The area surveyed is about two miles above the junction of Spencer's Creek with the Snowy River, about six miles east of the summit of Mt. Kosciuszko, and at an average elevation of about 5,700 feet above sea level. The specific information sought by the survey comprised the following: depth and nature of the bedrock, contours of the bedrock surface, nature of the overburden, and in particular, variations in physical properties occurring either horizontally or vertically. The seismic refraction method was used in the survey. This report gives an account of the geophysical survey and its results.

The Mosquito Creek Wolfram Field was visited on 6th and 7th October, 1951. This report gives a brief account of the inspection. The general geology of the area, the ore-bearing reefs, and the mining leases inspected, are described.

This report describes the results of a micropalaeontological examination of samples from bore No. 8253. Results are given for samples taken from the depth of 50 to 1000 feet down.

This report covers the results of a seismic reflection traverse on a portion of the Giralia anticline which has been mapped in Mesozoic and Tertiary rocks in the North-West basin. The work constitutes a part of a general programme of investigation which the Bureau of Mineral Resources, Geology and Geophysics, has been carrying out on Permit areas held by Ampol Petroleum Ltd. in this area. The seismic traverse described herein lies along the main road joining Giralia and Bullara homesteads and crosses the northern end of the Giralia structure. Tests were made with shooting in shot holes and also by air shooting. In addition, a refraction spread was shot along the axis of the anticline. This report gives an account of this investigation. Technical matters, such as interpretation technique and the symbols used in plotting results, are briefly noted. The results of the study and subsequent conclusions are discussed.

The samples from Margaret Bay were collected by H.B. Owen during a recent visit to the northern coast of Australia. The collection was made with the hope that microfossils may be found in the rocks which were collected from a twenty foot section exposed at Margaret Bay. The results of the micropalaeontological examination are discussed herein.

The Northern Territory is an integral part of the great Australian Pre-Cambrian shield which underlies almost the whole of Western Australia and the Northern Territory, much of South Australia and portions of New South Wales and Queensland. In most parts of the Continent, Pre-Cambrian rocks were welded into a stable shield before the end of Pre-Cambrian time, and in the Northern Territory itself the structural framework was established, and most of the mineral deposits introduced by an orogeny which terminated geosynclinal sedimentation about the end of the Lower Proterozoic. This discussion of the structure of the Territory in relation to mineralization is mainly concerned with Pre-Cambrian, and in particular with Lower Proterozoic rocks. Only a broad outline of the subject is given here.