The Berner mafic complex, part of the Avalonian arc system in central Georgia, comprises a series of layered metavolcanic gneisses, of mafic to felsic compositions, that have been intruded by a series of plutonic rocks. Ultramafic rocks occur either as thin layers within mafic plutonic rocks, or as layers and pods within layered mafic gneisses. All ultramafic rocks within the complex are metamorphosed, highly altered, and penetratively deformed. Consequently, their origin is somewhat problematic, although most are considered to be comagmatic with their mafic host rocks. The current spatial distribution of mafic-ultramafic bodies within the layered-series gneisses of the Berner mafic complex is considered to result from the heterogeneous, postemplacement tectonic disruption of a series of mafic-ultramafic plutonic rocks that were intruded at various times into a developing arc complex.