In the north the plateau is overlain by red and purple unfossiliferous sandstones, capped near its edge by a cherty limestone also unfossiliferous but possibly of Lower Cretaceous age.
This series is overlain unconformably by a younger quartzite of similar character, and itself rests upon the crystalline schists.
In the region of Adigrat the metamorphic rocks are invariably overlain by white and brown sandstones, unfossiliferous, and attaining a maximum thickness of moo feet.
Large areas are overlain with trachyte, basalt, obsidian, tuff and pumice.
This system rests unconformably on the Witwatersrand series and is unconformably overlain by the Transvaal system.