3. MADRID DURING THE PALAEOZOIC AND MESOZOIC (545 – 251 MILLION YEARS AGO)

Plant impressions

Municipality of Guadalix de la Sierra
Upper Cretaceous (80 Ma)

A collection of plant impressions from the Mesozoic flora of Madrid. Fragments of ferns, monocotyledon leaves, and compound leaves of Bennettitales (also known as cycadeoids; extinct plants resembling small palm trees), can be identified. Impressions of primitive angiosperms (fruiting plants), and remains of branches with needle-like leaves of a coniferous type, which may have reached a large size, are also preserved.

Arthropod invertebrates

Barranco de las Cuevas (Patones)
Middle Ordovician (470 – 460 Ma)

Lamellibranch mollusc

Barranco de las Cuevas (Patones)
Upper Cretaceous (75 Ma)

Calvero de la Higuera (Pinilla del Valle)
Upper Cretaceous (75 Ma)

The warm, shallow seabeds of the Upper Cretaceous in the Madrid region were home to reefs that were built by various organisms, including rudists (a type of extinct mollusc), bryozoans, sponges, and corals. Theses included solitary corals (close to Cunnolites or Cyclolites), and colonial corals (related to the genera Enallocoenia, Phyllocaeniopsis, and Columnastrea).

Calvero de la Higuera (Pinilla del Valle)
Upper Cretaceous (75 Ma)

The shallow tropical seas that developed during the Upper Cretaceous provided the habitat for various species of invertebrates and vertebrates, such as bony fish. They fed on molluscs and other animals with external shells, and thus developed a distinctive, button-like tooth morphology adapted to crushing shells.

Teeth and vertebrae of a marine reptile

Calvero de la Higuera (Pinilla del Valle)
Upper Cretaceous (75 Ma)

These are the only reptile remains from the age of the dinosaurs, found so far in the Madrid region.
Carentonosaurus is a marine reptile with a narrow, elongated body and very small limbs. Its vertebrae exhibit pachyosteosclerosis, a thickening of the walls of these bones that acts as weight during diving.

Calvero de la Higuera (Pinilla del Valle)
Upper Cretaceous (75 Ma)

One hundred redeposited teeth belonging to Cretaceous chondrichthyans have been recovered from the Pleistocene strata of this site. The teeth have allowed us to expand the geographic distribution of some shark species, that had not previously been identified on the Iberian Peninsula.

Calvero de la Higuera (Pinilla del Valle)
Upper Cretaceous (75 Ma)

The shells are primarily preserved in the sea urchins from the Cretaceous seas, while their spines do not usually fossilise because they are not mineralised, in most cases. Regarding the specimen in question, from the Upper Cretaceous limestones and dolomites of Pinilla del Valle, the pentaradial symmetry which is typical of these organisms is clearly evident.