The Hopefield site lies 300 ft. above sea-level, on the margin of the ‘Sandveld Plateau’ and ten miles inland from Saldanha Bay. It marks the inner margin of limestone ridges (Dorcasia Formation), product of a littoral dune invasion lasting from the Kamasian into the Gamblian, where these give place to the silvery-grey quartz sands of the Sandveld. The characteristic fossil horizon is a nodular calcrete which apparently represents the drying pan floors in which the fossils accumulated. It is traversed by sinuous ferricrete ridges that are interpreted as ferruginized dune cores marking a preceding moister period; similar ferricretes are of regional extent and postdate the Minor Emergence at the coast. The fossil layer is capped by surface limestones and ferruginized sands, the latter representing a second moister period.