Palaeozoic Rocks of the Davey River, South-West Tasmania

Abstract

A conformable succession in Palaeozoic rocks occurs at the Davey River at the southern end of the Olga-Hardwood syncline in S.W. Tasmania, and consists of the following formations (with approximate thicknesses): (top) Unit 6 Unit 5 Unit 4 Sandstone Shale Sandstone, minor shale, Unit 3 Shale-sandstone alternation Unit 2 Pebbly sandstone (bottom) 10 metres 15 metres conglornerate 75 metres 0.,500 metres 0-.500 metres Unit Quartzite conglomerate 0-800 metres Formations 1, 2 and 3 are equivalent, on lithological and structural grounds, to the Bathurst Harbour Sequence of Jennings (1961). Unit 4 has lithological and faunal similarities with the Caroline Creek Sandstone of the West Coast Ordovician succession (Banks 1962b). Equivalents of the Florentine Valley Mudstone and Gordon Limestone are pwhably also present in the centre of the syncline, If these correlations arc correct the Davey River succession provides a link between the Bathnrst Harbour and West Coast successions, with the Long Bay Shale representing a marine formation which is present in the South-west but apparently absent on the West Coast.