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.