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  • 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.

  • Foraminifera were first recognized in the Permian sediments of Australia in 1882. Some systematic work on these micro-fossils was done up to 1905, but there was no further investigation until. 1937, since when five papers on Permian foraminifera have been published. However, about ten years ago, systematic sampling of outcrops, cores and cuttings from bores was commenced with the object of determining whether micro-faunal zones could be established. Core samples and drill cuttings from these bores: and the various outcrops have been examined by the writer and a microfauna identified. Surface samples from localities in New South Wales were also submitted by the Geology Department, University of Sydney, for micro-examination. From the information presented in the following sections of this bulletin, it will be seen that, although a considerable amount of research is still necessary before a definite system of zoning, based on the microfaunas, can be applied to the Permian rocks of Australia, such a system is possible. In the extensive collections of Permian rocks examined from the Hunter River District of New South Wales, assemblages of foraminifera rather than restricted species have proved useful for zonal purposes, and it will be shown that correlation of deposits in other States can be made, by means of these assemblages.

  • The oldest rocks found in this area are Pre-Cambrian and the youngest are Recent but on the whole the area is one of great stability and not many of the periods of geological time are represented. The Pre-Cambrian are found outcropping round the edge of the basin and for simplicity in field work have been divided into five divisions. These are Tennant Creek, MacArthur R., Buldiva, Helen Springs, and Barkly Downs. This report provides a field summary of geology by division.

  • Results of a micropalaeontological examination of samples taken from between the depths of 1450 and 1800 feet.

  • The region under review may be broadly subdivided into three distinct geological and geophysical areas which are here discussed as separate entities. The geology, physiography, and mineral resources of each area, and the future mineral prospects of the region as a whole, are discussed in this report.

  • The Cow Flat Area was visited on the 12th March, 1947, with the object of ascertaining possible dolomite reserves. This information was required in connection with the application by Metropolitan Lime and Cement Company Ltd., owners of a dolomite quarry at Wall's Siding, near Mudgee, for financial assistance from the Commonwealth Government. It was desired to ascertain whether, in the event of the latter company ceasing production, the Cow Flat deposit could provide sufficient dolomite to supply New South Wales requirements. The situation, production, geology, origin and reserves of the dolomite deposits are discussed in this report. The report should be considered supplementary to Report No. 1946/005 and the Report on Limestone and Dolomite Deposits at Cow Flat and Wall's Siding (1947/090).

  • The geology and ore reserves of the dolomite deposit near Wall's Siding are discussed in this report. The report should be read in conjunction with the report on "Limestone and Dolomite Deposits at Cow Flat and Wall's Siding, New South Wales" (Record 1947/090).

  • Results of a micropalaeontological examination of samples taken from a depth of 1,125 feet down to 1,450 feet.

  • An examination was made of a proposed dam site at Geehi in April, 1947. The report comprises notes on access, general geology, evidence gathered from aerial photography, and the suitability of the site. Three accompanying plans, and a petrographic report on rocks collected from the vicinity, are appended to this report.

  • Results of a microexamination of samples taken from a depth of 5 feet down to 147 feet.