The recently updated Global Paleomagnetic Database provides an opportunity to construct a preliminary model of long-term magnetic polarity reversal behavior for the last 570 My. After filtering for quality, a sub-set of data from this global database is used to estimate relative reversal frequency, and the results show the expected long intervals of low reversal rate during the Cretaceous Normal and Permo-Carboniferous Reversed Superchrons. In addition to the established superchrons, these new results indicate a long period of very low reversal rate in the Ordovician, which may be a previously unidentified superchron, and an additional short period of anomalously low reversals at the Jurassic/Triassic boundary. If the Ordovician reversal rate anomaly is a single polarity superchron, it represents the third major change in reversal rate within the Phanerozoic, with approximately 200 My between the CNS, the PCRS and the new Ordovician reversed interval. ¿ American Geophysical Union 1995