The Cambrian biostratigraphy and chronostratigraphy of the Iberian Peninsula has been studied since the beginning of the past decade by the Spanish Working Croup of the ICCP projects, 29 and 303, followed by palaeogeographical studies within the ICCP project 319. Numerous sections in Spain and Portugal have been sampled for trilobites, arqueocyaths, acritarchs, small shelly fossils, microbiotas and trace fossils. In this way a stratotype for the Precambrian/Cambrianboundary was proposed in Central Spain, and at the same time the former regional stages Ovetian, Marianian and Bilbilian (and the new Cordubian Staged for the Lower Cambrian were revised. The Leonian and Caesaraugustian stages have also been proposed for the Middle Cambrian while, a third and younger Middle Cambrian stage is now being studied in Northern Spain and Southern France. This Cambrian chronostratigraphical scale is now applied elsewere in South Europe by foreign research groups. Studies in palaeoecology and event stratigraphy have permitted to subdivide the Spanish Lower Cambrian into transgressive/regressive sequences. They have been correlated with other events of similar age from other countries and continents.
By means of both chronostratigraphic and event stratigraphy scales, it has been possible to summarize the Spanish Cambrian System into palaeogeographical maps and to stabllsh this palaeogeographical evolution as related to a generalized rifting process
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