The Ordovician, Silurian and lower Devonian rocks of the
Domes area (near Figueiro dos Vinhos), in central Portugal, form
a continuous sedimentary sequence approximately 1450m thick. Folded
Pre-Ordovician "Complexo xisto-grauvaquico" (CXG) is unconformably
overlain by a transgressive quartzite, mudstone and greywacke
succession of four Ordovician formations which are locally shelly
and graptolitic. These formations are: Serra do Brejo Formation,
Brejo Fundeiro Formation, Monte da Sombadeira Formation and Monte
do Carvalhal Formation. The Ordovician rocks are conformably overlain
by a Silurian sequence of graptolitic mudstones passing upwards
into sandstones; these beds include the Vale da Ursa Formation,
Foz da Serta Formation, Vale do Serräo Formation, Serra da Mendeira
Formation and part of the Serra do Luacäo Formation. The Devonian
rocks are represented by part of the Serra do Luagao Formation and
the Dornes formation, a sandstone-madstone sequence passing up into
Shelly limestones.
Most of the Ordovician faunas are described and discussed
including sixteen species of trilobite, five species of brachiopod
and eleven ichnospecies of trace fossil. Faunal lists of material
identified by specialists in the fields of Ordovician and Silurian
graptolites, Ordovician echinoderms, Devonian brachiopods and
Silurian microfossils are also given. The Ordovician faunas belong
to the Selenopeltis province and show close links with those of Spain,
France, Morocco and Bohemia. The correlation and palaeogeography of the
Dornes area is discussed with emphasis on the Ordovician Period in
the Ibero-Armorican area
