The Silurian rocks of Spain occur in all the zones of the Iberian (or Hesperian) Massif, except the South Portuguese Zone. Silurian rocks also crop out in other parts of the Variscan Belt that were later affected by the Alpine orogeny, in the Pyrenees, the Catalonian Coastal Ranges, the Iberian Cordillera and the Betic Cordilleras (Fig. 5.1). As in other regions of the North Gondwanan Province, the Silurian deposits of the Iberian Peninsula comprise mainly terrigenous sediments dominated by pelagic faunas. The most characteristic rocks are graptolitic black shales (the socalled ‘ampelites’) and the commonly mentioned uniformity of the Silurian succession mainly results from the special attention that has been paid to these richly fossiliferous rocks. Other types of rocks also occur in the Silurian sequences, however, and allow distinctions between different types of succession, as well as providing extra evidence for environmental conditions and palaeogeographical setting.
We consider that, from Cambrian to Devonian times, with the exception of the South Portuguese Zone that probably belonged to Avalonia (Oliveira & Quesada 1998, and references therein), the whole Iberian Peninsula was part of the North Gondwanan Province that extended along the northern margin of the African part of the Gondwana continent (Robardet et al. 2001, and references therein). The Silurian palaeolatitude of the Iberian Peninsula cannot be defined precisely, either from climatically sensitive lithofacies or from faunas, as the successions are almost entirely terrigenous and the faunas mainly pelagic. Available palaeomagnetic data are not clearly