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.

The two samples submitted for micropalaeontological examination, came from the depths of 290 feet and 320 feet respectively. They consisted of hard, grey, carbonaceous shale. Crushings of the rocks yielded a small assemblage of arenaceous foraminifera and pyritic casts of ostracoda of Permian age. A list of the forms in each sample is as follows.

The prospect was a second order anomaly located by the Airborne Scintillometer Survey of 1952. After preliminary ground investigation, a survey grid was set out by the geophysical section. The base line runs east-west for 800 feet. The traverse lines are spaced 100 feet apart and pegged at intervals of 100 feet. The detailed radioactive coverage constituted the main survey. Plate 1 shows the results of this survey. Area No. 2 was the first located and the grid was laid out with the outlining of this area in view. As work progressed area 1 was discovered and later area 3. Time did not allow the grid to be extended to indicate clearly the third area. A detailed magnetic survey supplemented the geiger work. The results are shown on Plate 2. The work commenced in July and was completed in September, 1953.

A radiometric survey was made, by carborne equipment, of the area of granitic country south-west of Edith Siding that was covered by the airborne scintillometer survey of 1952. Several small, lenticular deposits of radioactive, hematitic lode material were found in three shear zones, but the radioactive anomalies were in general due to hills of granite which have counts higher than the general background count. A similar carborne survey, and an investigation by a geochemical party, were made in an area of Brocks Creek sediments south-east of the Edith Siding, in which twelve third order anomalies had been indicated by the airborne survey. The anomalies were found to occur mainly along a slaty band, and along a prominently outcropping bed of tuffaceous sandstone. A shear or fracture zone near the southern end of the area investigated contains oxidized copper minerals, and Geiger counts a little higher than usual were obtained at one locality within it, and at another locality approximately 200 feet east of it. The largest of the hematitic lenses in the granitic country south-west of the Edith Siding will be inspected and sampled, and additional prospecting will be done along and adjacent to the copper bearing shear zone.

The following report contains descriptions of thin sections of 17 rocks collected from cores and outcrops in the Muswellbrook area. This report is for information of officers in the area, who have retained duplicate hand-specimens. Specimens are numbered 1 to 18, and description of one specimen collected (No. 13) is not given here. Discussion of this rock is of academic interest only, and time has prevented its incorporation in the following report.

These documents have been scanned by the GA Library. Please refer to the document for contents.

These documents have been scanned by the GA Library. Please refer to the document for contents.

Legacy product - no abstract available

Legacy product - no abstract available

Drastic changes in ideas of the age of some of the marine Tertiary deposits in Australia have been necessary in the last few years. The recognition of Eocene over a wide area in south-eastern Australia is the result of considerable detailed mapping of deposits in south-western Victoria and the subsequent detailed investigation of the sediments for microfaunas. The discovery of the Eocene foraminiferal genus Hantkenina at different localities in south-eastern Australia has been an important factor in bringing about the recognition of the Eocene. The discovery of Hantkenina at Bird Rock, Torquay, Victoria, the type locality for the Janjukian Stage of Victorian Tertiary stratigraphy, confirms an Eocene age for beds which had previously been placed in the Upper Oligocene or the Miocene. The type section for the "Anglesean Stage" at Anglesea, west of Torquay, which has been regarded as Oligocene, is now placed in the Middle Eocene. The beds at Anglesea stratigraphically underlie those containing Hantkenina at Torquay. At least 4,000 feet of the Middle Eocene beds have been proved in bores. In western Victoria it is quite probable that Lower Eocene to Paleocene beds exist. There is still doubt as to whether definite marine Oligocene beds exist in Australia. Certain non-marine deposits thought to be of Lower Oligocene age are now Middle Miocene. Ideas of age of the beds in the Upper Tertiary have undergone little change. The calcareous sandstones of the Adelaide Basin in South Australia are regarded as Lower Pliocene rather than Middle or Upper Pliocene of certain authors.