Paleozoic rotation of the Siberian craton along transform faults on the western Laurussian margin is a hypothesis that incorporates geologic and paleomagnetic evidence. The hypothesis could ultimately explain the origins of allochthonous Paleozoic terranes in the western North American Cordillera and northeast Russia, and supports a Precambrian connection of the Siberian craton to southwest North America. The hypothesized rotation may have opened a marginal sea leading to deposition of nearly identical early Paleozoic shelf sequences on the conjugate Cordilleran and Verkhoyansk margins. The model proposes that tectonic shearing transferred a series of terranes from Laurussia to the Siberian plate. The transforms evolved into convergent boundaries in the middle and late Paleozoic. The displaced terranes were ultimately accreted into the Cordillera and orogenic belts in northeast Russia.