Notes on a small collection of opalized shells, bone fragment and specimen of precious opal from White Cliffs.

Shortly after I took up the appointment of Mineral Economist, the high quality of the mica from the Harts Range came to my notice. Accordingly, I paid a visit to Harts Range between the 22nd September and 4th October. In judging the possibilities of developing the mica deposits of the Harts Range, the difficulty is the almost complete lack of reliable detailed mining data in the past - production data for the later war years only are available. However, by comparing the degree of areal concentration of the pegmatites, the type of deposits and the quality and sizes of the mica so far produced with those in India, a reasonable picture can be obtained of comparative possibilities. The method of approach throughout this report, therefore, will be comparison of the Harts Range with India mica. This report gives an account of the present state of the Australian mica industry, including descriptions of current trade terms, the grading and classification of mica, and the Harts Range Mica Belt deposits. Suggestions and recommendations for the development of the industry are discussed.

Results of a micropalaeontological examination of samples from a depth of 2 feet down to 1185 feet.

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).

Results of a micropalaeontological examination of samples taken from the depth of 3 feet down to 534 feet.

The known bauxite deposits near the township of Ouse are No. 1 on Glen Dhu Estate, Nos. 2, 3,4 and 5 on Gladfield Estate, and Nos. 6, 7, 8, and 9 on Leintwardine Estate, Nos. 10, 11, 12, 13 and 14 on Lachlan Vale Estate and No. 15 on Lawrenny Estate. Examination of all the occurrences and testing of the more promising by shaft sinking and boring was conducted. The results of this work are discussed in the report.

Results of a micropalaeontological examination of rock samples taken from various sites in the vicinities of the Desert and Bonaparte Gulf Basins.

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.