Lower and Middle Ordovician rocks outcropping in the Cabañeros National Park (Central Iberian Zone)
are being explored within a mapping project aimed at identifying geosites representative of the geological
and paleontological heritage on this natural area. Ongoing field-work has led to the discovery of three
fossil localities that bring out significant paleontological data relevant to the whole Iberian Massif. The
oldest comes from the upper part of the Armorican Quartzite Fm. (Floian/middle Arenigian) and is a large
ichnofossil identified as Tumblagoodichnus? isp., which probably represents a shallow burrow filled by
collapse of sand from above, and dug as a temporary refuge by a large arthropod. The trace is 45 cm wide,
much bigger than the large arthropod traces previously reported from the Iberian Ordovician (rare Cruziana
reach up to 26 cm in width). The second fossil locality lies towards the middle part of the overlying
Marjaliza Beds (Dapingian to lower Darriwilian/middle-upper Arenigian) and is represented by a thick
coquina of paleotaxodont and paleoheterodont bivalves, apparently formed due to a catastrophic event
(an exceptional storm?) that transported and entombed en masse millions of individuals now preserved as
complete specimens with closed valves. This local abundance strongly contrasts with the scarcity of Arenigian
bivalves preserved in the Cruziana sandstone facies of SW Europe. Finally, the youngest locality is a rich
fossiliferous bed of lower Oretanian (Darriwilian) age recorded in the Navas de Estena Shales, where the
brachiopod genus Eodalmanella (Ranorthidae) makes its second European occurrence and reinforces the
Ibero-Bohemian paleobiogeographic affinities
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