This study will conduct paleomagnetic analyses of lower Paleozoic-aged rocks in Britain in order to define the movement of Eastern Avalonia and closure history of the Iapetus Ocean during the Silurian and Ordovician. A broad picture of the paleogeographic setting of Eastern Avalonia has been recently developed and this work will provide much needed constraints. The results will be of broad significance to plate tectonic reconstructions of the Appalachian - Caleonide orogen. They will also provide additional criteria for the recognition of remagnetization phenomena, which is of considerable importance to geophysicists interested in tectonic problems.