Two samples of diatomite were recently received from Broken Hill Pty. Co. Limited for microscopic examination. They were from Nettle Creek, 9 miles north-east of Mt. Garnet and near Innot Hot Springs. The results of the microscopic examination are given in this report.

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Legacy product - no abstract available

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Exposure of the Horn Valley Siltstone is usually poor, but well preserved material can be obtained from some of the fully cored wells intersecting this interval throughout the Amadeus Basin. In this study, the following cored holes were used: Henbury #4, Henbury #6, Mt Liebig #2, Tempe Vale#1 and Tent Hill #1. I have subdivided the formation into ten informal members, HV1(lowermost) to HV10, which reflect vertical lithofacies variations in a shallow marine shelf environment. These members have been defined primarily from sedimentological and palaeontological information such as the presence or absence of body fossils, mode of preservation, species associations within groups of fossils, presence or absence of bioturbating organisms (trace fossils), lithology and bedding types. It can be inferred that the amount and composition of organic matter preserved in the sediment was determined largely by the concentration of oxygen in the bottom water and the extent to which the sediment was disrupted by burrowing organisms because burrowing and scavenging activities of benthic organisms are controlled by the concentration of oxygen in the bottom water. Organic geochemical data fromTempe Vale #1 and Tent Hill #1 were used to confirm these facies variations. The transition between HV6 and HV7, which can be recognised easily by the sudden change in shale to carbonate ratio, has been found to coincide with the presence of high organic rich sediments, with recorded TOC values of up to 6.30%.

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fossils housed in Canberra, and administered by the Australian Geological Survey Organization (AGSO), previouslyknown as the Bureau of Mineral Resources, Geology & Geophysics (BMR). It originated with the appointment of aCommonwealth Palaeontologist in 1927, and since the 1950's has grown from a small collection of about 1,000specimens to its current size of over 30,000 specimens which have been described, figured, or referred to in scientificpublications. The rapid increase in size in recent years reflects a strong research effort to document fossil faunas andfloras from important localities throughout Australia, as well as Papua New Guinea, Australian Antarctic Territory,and the seafloor of our continental shelves. All of these areas have been the subject of geological investigations byAGSO. The CPC forms a taxonomic database which underpins all biochronological dating of AustralasianPhanerozoic sedimentary sequences, and thus forms the basis for biochronological age control using various fossilgroups, which is an integral part of most geological investigations concerned with stratified rocks. Such investigationsinclude geological mapping projects, and subsurface analysis of Australasian sedimentary basins, which areundertaken by AGSO in support of petroleum and mineral exploration and land use activities throughout the continent.

Mollusca from the Nanutarra Formation, a recently defined strata! unit cropping out along the north-eastern edge of the Carnarvon Basin of Western Australia, are described and the age of the' formation is discussed. The fossils occur largely as moulds of the original shells, so that their study has been based mainly on artificially prepared casts. Of about 48 forms recorded in the paper, only one (Pseudavicula anomala) has been definitely referred to a previously described species, four (Maccoyella aff. corbiensis. M. aff. barklyi, M. aff. moorei, and Modiolus aff. ensi/ormis) have been assigned qualified identifications with known species, and 18 are described as new; the remainder have been given only generic identifications, owing to the limitations of the material. The new species are as follows:-Nuculana hoelscheri, Glycymeris mckellari, Pacitrigonia? nanutarraensis, Pterotrigonia australiensis, "[socyprina" fairbridgei, "Corbicellopsis," nanutarraensis, Lucina macroporum, Mutiella? teicherti, Protocardia wapeti, Astarte (Nicaniella) mcwhaei, Eriphyla playjordi, Pleuromya ashburtonensis, Panopea glaessneri. CQrbula nanutarraensis, Muricotrochus? australiensis, Purpurina? yanreyensis, Procerithium (Rhabdocolpus) brunnschweileri, and" Acteonina" australiensis. Apart from the species of Pseudavicula, Maccoyella, and Modiolus, which have been identified, mostly with qualification, with Australian Lower Cretaceous species, the fossils bearing particularly on the age of the formation are those belonging to the genera Pterotrigonia (hitherto solely Cretaceous apart from one record from the Tithonian), Eriphyla (hitherto mainly Cretaceous, but known from the Upper Jurassic), Glycymeris (known from the Cretaceous but not from the Jurassic), and large Panopea (resembling several Cretaceous species and unlike any from the Jurassic). No species belongs to an exclusively Jurassic group. It is concluded that, notwithstanding palaeobotanical evidence of a Jurassic age, the Nanutarra Formation should be most probably referred to the Lower Cretaceous. It has yielded no ammonites or brachiopods.

Beyrichicopids and kirkbyocopes are represented in the Early Carboniferous benthic ostracod fauna of the Bonaparte Basin by at least 29 species referable to 18 genera (including two that are probably new, but unnamed). The described number of species are distributed among the ostracod families. Of the species described, eight are new (Libumella bonapartensis, Welleriella atypha, Malnina spinosa, Coryellina excaudata, C.robertsi, Selebratina serotina, Tetrarhabdus dictyon, and Scrobicula inaequalis), eight are closely related to, if not conspecific with, established taxa [Pseudoleperditia cf. venulosa, Coryellina cesarensis, Kirkbya aff. lessnikovae, K. aff. quadrata, Amphissites aff. centronotus, A. umbonatus, Kirkbyella (Berdanella) quadrata, and Scrobicula aff. inaequalis), and 13 are placed in open nomenclature, most of which are comparable with previously described taxa. The morphological similarities of the extinct Kirkbyacea and the extant Punciacea are discussed, and possible homoemorphic resemblances between them are considered. Detailed SEM examination of the reticulation pattern of the kirkbyacean species Amphissites sp.B revealed the results of epidermal cell-division during the ecdysis between the A-I stage and the presumed adult stage. Mitosis of the epidermal cells not only increases the valve surface area, but also initiates carinae by the fusion of adjacent muri of twin fossae. An interim biostratigraphic scheme for the Early Carboniferous sequence of the Bonaparte Basin consists of a succession of eight ostracod assemblages that are based on the first appearance (in ascending order) of the following species: Welleriella atypha, Coryellina robertsi, Shivaella cf. armstrongiana, Coryellina cesarensis,. Malnina spinosa sp. nov., Selebratina serotina, Scrobicula inaequalis and A mphissites sp.B. The scale of assemblages is controlled by conodont and foraminiferal zonations, and is calibrated against the Dinantian time-scale. So far, the atypha, robertsi and armstrongiana Assemblages have been recognised in the Early Carboniferous (Tournaisian) sequence of the Canning Basin. The major affinities of the Early Carboniferous beyrichicopids and kirkbyocopes from the Bonaparte Basin are with cognate species from Western Europe (Belgium, northern England), the Russian Platform, Kazakhstan, and Tibet. North American affinities are of minor significance. In general terms, the entire Early Carboniferous ostracod fauna from the carbonate shelf sediments of the Bonaparte Basin belongs to the Bairdiacea-Paraparchitacea ecozone, suggesting warm climatic conditions. The Tournaisian (Burt Range Formation; Septimus Limestone) faunas may include ecologically mixed assemblages, i.e., marine nearshore and shallow offshore, but the palaeoecological studies needed to test this model must await the description of the total Early Carboniferous ostracod fauna. The Visean (Utting Calcarenite) Kirkbyacea are as frequent (in species abundance) as the Paraparchitacea, both superfamilies ranking second to the Bairdiacea; a proportion indicative of open-marine shallow offshore conditions.