Certain Permian lavas, Devonian, Cambrian and Pre-Cambrian sediments are shown to be permanently magnetized in directions different from that of the present geomagnetic field. All the Palaeozoic rocks examined possess southward natural remanent magnetizations. Whilst it is not suggested that the geomagnetic field did not reverse during the whole of the Palaeozoic, it is believed that the collection from the Lower and Upper Old Red Sandstone is sufficiently representative to make reversals during these times most improbable. The Wentnor Series of Pre-Cambrian rocks of the Longmynd shows reversal of magnetization about an axis which is not significantly different from that determined for the Torridonian series of north-west Scotland in a preceding paper. This is taken to support the view that they are roughly contemporaneous.