Smaller outcrops of Proterozoic gneisses and Cambrian granites are scattered along the eastern coast south of the largest area of outcrop in the Vestfold Hills. The red bed sequence consists of sandstone interbedded with claystone and siltstone that may reach a thickness of 2-3 km in the center of the Prydz Bay Basin. The sediments are brown red to green gray in color. Sandstone units are as thick as 3 m and are medium to coarse grained, fining up to siltstone and claystone. The matrix is a mixture of chlorite, sericite, biotite, and muscovite.
Feldspars are mostly orthoclase and microcline with very little plagioclase.
Sand grains are predominantly quartz and feldspar with garnet, biotite, and illmenite accessories. Siltstones and claystones are rich in plant fragments with some ripple cross-laminations, and rootlets beds. They form coarsening-up sequences suggesting deposition in crevasse splay deposits in swampy, vegetated floodplains. Sandstone units were probably deposited in low-sinuosity fluvial channels. There are no indications of marine deposition.