The global absolute paleointensity (PINT) database, sponsored by the International Association of Geomagnetism and Aeronomy, recently was updated with new data and published alongside a new queryable interface at http://earth.liv.ac.uk/pint/. Absolute paleointensity determinations are spot readings of the strength of the geomagnetic field at the time and place at which a rock cooled down from elevated temperatures. The time generally can be estimated using an independent dating technique applied to the rock itself, and the place (or at least the paleolatitude) of the rock often can be estimated from the associated paleomagnetic direction.

The availability of a large body of palaeomagnetic data from Eastern and Western Iceland has made possible several deductions about the nature of the source of the geomagnetic field. We conclude that the assumption of a centred dipole source leads to a simple and reasonable time-average dependence of absolute dipole strength on dipole orientation (dipole moment on pole position). The relationship is nearly axially symmetrical, and provides natural definitions of ' normal ' and ' reversed ' fields. The normal state has been more stable over the past 12 My than the reversed state.The dependence of time-average dipole strength on dipole orientation provides a considerable constraint on any postulated mechanism for field generation, although it does not necessarily give direct insight into the behaviour in the core.

This paper concerns palaeomagnetic studies of 10 lava sequences in southwestern Iceland. The sequences contain 329 lavas. Specimens which have been A.F. demagnetized provide palaeomagnetic polarities which agree very well with Tr. Einarsson's earlier compass studies of the same sequences in the field. Little new information is provided about the stratigraphic correlations among the various sequences investigated. Interpretation still depends essentially on Einarsson's original field mapping.Mean N and R pole positions are not significantly different, but are both on that side of the geographic pole far from Iceland, which conforms with the world-wide pattern recently emerging.Three transition zones provide new evidence about the behaviour of the geomagnetic field during inversion of polarity. Sub-

Summary: Statistical issues in the analysis of neuroim ages are reviewed, These include biological questions of interest, basic problems of measurement and experimen tal design, normalisation, standardisation and transforma-

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