Abstract
An analysis of early Tertiary palaeomagnetic data from the Pacific, North America, Greenland and European plates is presented. A correction for discrepancies in palaeomagnetic directions and pole positions of this age resulting from plate motions has been attempted by means of two independent techniques: (i) palaeoequator determinations from Deep Sea Drilling Project Pacific cores, and (ii) identification of the Icelandic hot spot as a fixed reference frame. The corrected palaeomagnetic data from the Pacific and North American plates are inadequate to allow firm conclusions to be drawn, but the data from Greenland and Europe appear to indicate that the time-averaged departures of the geomagnetic field from a centred axial dipole configuration during the past 25 Ma, identified by R. L. Wilson (1970) , might in fact have persisted for at least 53 Ma.