The South Norway Precambrian Region is underlain by gneisses and migmatites, gneissic and massive granites, metavolcanic rocks, quartzites and varying amounts of other metasedimentary rocks, anorthosite, amphibolite, and mafic plutonic rocks. Rocks and minerals yield radiometric ages ranging from c. 1750 m.y. to c. 800 m.y. Based on analogies in terms of lithological variation and spatial distribution of supracrustal and infracrustal rock complexes, several lines of evidence indicate that the region probably constitutes the remnants of an andean-type continental margin and a segment of a cordilleran- type orogen approximately parallel to the present coastline of south Norway. 'TheTelemarkian Orogen' is suggested as an informal term for this Proterozoic orogen. In terms of stratotectonic and morphotectonic evolution, the Telemarkian orogen shows important similarities to the Columbian Orogen of the Canadian Cordillera.