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Favosites sp.
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Favosites is a relatively common and widespread genus of corals in the Devonian. It is a tabulate colonial coral, made up of tightly packed corallites that are usually hexagonal in shape. They are sometimes known as honeycomb corals because of the structure they thus have. The walls of the corallites are thin and shared, and perforated by holes, known as mural pores, which allowed nutrients to be exchanged. In the specimens of black limestone shown here, this structure isn't easy to see in the field or on hand specimens of rock . We have tried various methods to improve the visibility of the fossils, including polishing sections, etching them with acid, and making acetate peels. None have been very successful, and it may better detail will probably require the use of thin sections. By zooming in on the polished sample, however, it is just possible to detect the outline of the corallites. In the section above, taken roughly at right angles to the direction of growth, cross-sections of the corallites are visible, some showing short radial septae, and the thin, ragged line of the walls. In the top left corner of the image below, which provides a longitudinal section, it is just possible to see the tubes of the individual correlates, and the tabulae that divide them and were the chambers in which the organism lived.
Given the difficulty in distinguishing details of these specimens, it isn't easy to define the species to which they belong. Favosites murrumbidgeensis is a possibility, however, since this has been recognised in the Reeftom Formation, either in a growth form or in a toppled position seemingly close to where they grew. This suggests that it is one of the reef-building species at the time. F. murrumbidgeensis is also significant because it seems to be absent from the Baton River Formation, but is present in the Lower Devonian rocks of SE Australia. It thus provides a link between Reefton and Australia at the time - part of the so-called Bohemian fauna that characterised the Emsian stage - but separates it from the Baton Formation,, which appears to be slightly older and contain a more endemic (i.e. local) fauna. But further study, and more samples, are needed to confirm the species.
Given the difficulty in distinguishing details of these specimens, it isn't easy to define the species to which they belong. Favosites murrumbidgeensis is a possibility, however, since this has been recognised in the Reeftom Formation, either in a growth form or in a toppled position seemingly close to where they grew. This suggests that it is one of the reef-building species at the time. F. murrumbidgeensis is also significant because it seems to be absent from the Baton River Formation, but is present in the Lower Devonian rocks of SE Australia. It thus provides a link between Reefton and Australia at the time - part of the so-called Bohemian fauna that characterised the Emsian stage - but separates it from the Baton Formation,, which appears to be slightly older and contain a more endemic (i.e. local) fauna. But further study, and more samples, are needed to confirm the species.