The correlation of biozonations to the Late Jurassic-Early Cretaceous GPTS has been accomplished largely by land section magnetostratigraphy in the Mediterranean area. The polarity pattern in the Larson and Hilde [1975] block model, particularly in the M0-M20 interval, has been replicated in numerous land sections. The only modification of the Larson and Hilde [1975] polarity pattern is the presence of an additional reversed polarity chron slightly older than CM11. This additional polarity chron has been observed in land section [ Channell et al., 1987] and in the oceanic magnetic anomaly record [ Tamaki and Larson, 1988].
For the CM0-CM20 (mid-Tithonian to early Aptian) interval, magnetostratigraphy in pelagic limestones in Italy has yielded correlations of the GPTS to nannofossil events/zonations [ Bralower, 1987; Bralower et al., 1989; Channell et al., 1987; Ogg et al., 1991a; Channell and Erba, 1992], to calpionellid events/zonations [ Channell and Grandesso, 1987] and to occasional ammonite finds [ Cecca et al., 1994]. Ammonite-bearing nodular limestones in Spain have provided correlations of the GPTS to ammonite zonations at the Berriasian/Valanginian boundary [ Ogg et al., 1988], and in the Kimmeridgian/Tithonian [ Ogg et al., 1984]. The ammonite-bearing sections permit direct correlation of the GPTS to stage boundaries, however, the nodular limestone (Ammonitico Rosso) facies has low and variable sedimentation rates inhibiting polarity pattern correlation to the GPTS. For (pre-Kimmeridgian) oceanic magnetic anomalies older than M25, the correlations to magnetostratigraphic section (and hence to ammonite zones and stage boundaries) are very uncertain due to the lack of a distinctive ``fingerprint'' in the polarity pattern and low/variable sedimentation rates in the land sections [e.g. Steiner et al., 1986; Channell et al., 1990; Ogg et al., 1991b]. The oldest oceanic magnetic anomalies are probably Callovian or Bathonian in age, although age control is poor due to uncertain correlation to land section magnetostratigraphies. The GPTS prior to this time must be constructed without the oceanic template, by piecing together land section magnetostratigraphies. In the last quadrennium, considerable progress has been made in establishing biomagnetostratigraphic correlations for Early Jurassic, Triassic and Paleozoic time. This important effort is, however, beyond the scope of this review.