Intrusive and extrusive silicic rocks intertongue with mafic volcanics and sediments in the southern part of the Eden-Comerong-Yalwal Rift Zone. Late Devonian fish occur in the sediments. The present stratigraphic scheme of the ���Eden Rhyolite��� and the ���Lochiel Formation��� separated by an unconformity or disconformity is rejected. In its place, we rename the assemblage the Boyd Volcanic Complex, formed in a terrestrial zone of extension. The recognition that the alkaline Gabo Island Granite intrudes the Boyd Volcanic Complex, and that both are overlain by the Upper Devonian Merrimbula Group, provides a tight stratigraphic bracket on a potential point on the radiometric time scale. �� Taylor & Francis Group, LLC.