THE MEDITERRANEAN LOWER CRETACEOUS

northeast — the Cantabrian and Iberian mountain ranges, and to the southeast —•
the Subbetic zone with its continuation towards the Balearic Islands. In the north
the Iberian Peninsula is limited by the Pyrenees. A number of consistent studies on
the Lower Cretaceous were carried out in the past twenty years, among them notably
the works of R a t (1963), Rangheard (1971), R e у (1972), V i a 1 1 а г d
(1973), Canérot (1974), P e y b e r n e s (1976), etc.
4.1. Portugal
The Lower Cretaceous in Portugal is developed in the western periphery of the Iberian
Meseta: in the area of Estramadoura, Beira, Arrabida and Algarv. Continental
and epicontinental facies predominate.
Most representative are the sections in Estramadoura, which are studied in detail
by J. R e y (1972). The lithological transition from the Jurassic to the Cretaceous
is usually gradual.
In the area of Cascais, Sintra and Brouco the Berriasian is represented by the
following succession: limestones and marls with Mancellina purbeckiensis (F о rb
e s), covered by marls with Anchispirocyclina lusitanien (E g g e г), Nerinea infravalanginiensis
(С h о f f.), limestones and marls with Trocholina. In the region
of Ericeira and Cap Espichel the Berriasian is represented by alternation of variegated
claystones, dolomites and sandy limestones. These are sediments of Purbeckian
type.
The Valanginian is connected with two formations. The lower one is built of
shallow-sea limestones and marls with Natica leviathan (P i с t., Cam p.), developed
in the Sintra Massif and in the Caskais region. In the east these clayey-calcareous
sediments are replaced by sandstones ("grès de Vale de Lobos"), formed under
estuary conditions. The upper formation is developed in the Sintra area, near Brouco
and to the north of Cap Espichel. It is represented by reddish sandy limestones,
in some places ferruginized and oolitic ("calcaire roux") with Neocomites (N.) neocomiensis
(d'O г b.) and echinids.
The Hauterivian is developed in the area of Sintra and Brouco. It is represented
at its base by marls and clayey limestones with Toxaster, Crioceratites ex gr. duvali
and Neocomites sp. In the east these sediments pass into subreef limestones, well
developed near Brouco. The upper part of the stage is built of reef limestones with
corals and echinids. At the same time marls and sandstones were formed in the north
at Ericeira (Santa Suzana), followed above by limestones with Rudista (Praia des
Coxos). The Hauterivian near Cap Espichel is also developed in a similar facies.
The Lower Barremian is developed at Sintra and Brouco: limestones with Choffatella
and Dasycladacea.
The terrigenous-carbonate sediments of the Upper Barremian and Aptian
(Almargen Beds) are particularly widespread. These are varied limestones (dolomitic,
clayey, sandy-biodetritic, organogenous reef), marls and sandstones, testifying
to shallow-sea conditions and marking a regressive cycle which ends at the
end of the Gargasian Substage.
To the north of Torres Vedras the Lower Cretaceous passes into typical continental
deposits of Wealdian type: river sandstones with plant remains. The classical
outcrops of Serkal are found in this region, from where some of the oldest finds
of fossil plants from Dicotyledonae — Dicolylophyllum, are known.
4.2. Subbetic Depression
This depression is developed in Southeastern Spain and the Balearic Islands. There
are representative sections in the Andalusian area, in the regions of Grenada, Cor-
7 Th» Mediterranean Lower Cretaceoua
97