The sequence formerly mapped as Spero Bay Group (Lower Devonian) and containing the palaeontologically significant Point Hibbs Formation includes Lower Devonian, Ordovician and possibly Cambrian rocks. The Point Hibbs Formation (Lower Devonian) is redefined to include interbedded fossiliferous lime packstone and fossiliferous claystone, characterized by large coral heads. Gordon Group limestone contains a conodont and brachiopod fauna indicating a late Middle Ordovician age and includes fenestral-peloidal and oncolitic lithologies typical of the Gordon Group elsewhere in Tasmania. Strata of different ages are juxtaposed along east-dipping thrust planes. Differences in conodont colour alteration indices suggest a minimum relative vertical displacement of 2 km between the Point Hibbs Formation and the Gordon Group. High-level thrusting and westward transport direction may have been a general feature of Middle-Late Devonian deformation in western Tasmania.