The aim of this note is to draw attention to an ENE-trending, late Proterozoic metadolerite swarm that occurs 25 km south-east of Usakos in pre-Damara basement. The dolerites were first recorded by Gevers (1931) who described sills and sheets with relict ophitic texture and possible amygdales in the 'Abbabis System'. The swarm appears to crosscut large tracts of basement gneiss which underlie the southern Central Zone (CZ) of the Damara Orogen and to be largely responsible for the ENE-trending magnetic grain (Corner, 1983) of this terrane. The dykes run parallel to sub-vertical megashears (a recently identified shear belt; Steven, 1993) and are spatially associated with shear zone-hosted gold mineralisation. The Usakos metadolerites bear similarities with a mafic dyke swarm near Swakopmund (Jacob, 1988, pers. comm.). A possible relationship with the Gannakouriep dyke swarm of southern Namibia (Hunter and Reid, 1987; Ransome, 1991; Reid et al., 1991) is discussed.