The sediments of the Gambier Embayment are mainly of Cretaceous and Tertiary age. Lower Cretaceous subsurface units have been referred to outcropping rocks of the Otway and Merino Groups, but satisfactory criteria for their identification with surface exposures have not been established. Upper Cretaceous equivalents of Curdies and Paaratte Formations occur, and in equivalents of the Belfast Mudstone two faunal zonules recorded from the Belfast have been identified. An almost complete sequence of Paleocene to Lower Miocene sediments is described, and a zonal scheme based on planktonic foraminifera from Middle Eocene to Lower Miocene is proposed. The planktonic succession permits interregional correlation, since it closely approximates to a similar succession in New Zealand.