The late Proterozoic volcanic and sedimentary sequence in the Dordabis area, SWA/Namibia, has been named the Dordabis Formation and subdivided, on the basis of field, petrological and petrographic evidence, into the Opdam and Bitterwater Members. Relict phases including augite and minor plagioclase only occur in the Bitterwater metalavas, as recrystallisation is complete in the Opdam metalavas. The composition of the relict feldspars ranges from labradorite in the ophitic basalts to oligoclase in the blastoporphyritic metalavas. The feldspars in the Opdam Member are albitic in composition (An content 0,0 to 1,7). Epidote compositions are typical of those occurring in metabasic rocks. Samples with high-iron whole-rock compositions are accompanied by high concentrations of Fe3+ in concomitant epidotes.