The museum of the giant trilobites
From the fossiliferous deposit known popularly as the "Pedreira do Valerio" ("Valerian Quarry"), slates have been extracted since the mid-20th century, whose purpose is their transformation and their use in civil construction. Therefore, these slates have uncovered an important fauna of invertebrate fossils consisting of trilobites, bivalves, rostrous conquers, gastropods, cephalopods, brachiopods, echinoderms, hyoliths, conularias, ostracodes, graptolites and ichnofossils, initially considered as "animals flood time, "but today we know that these were people living on the shores of the Gondwana Paleocontinent, nearly 465 million years ago (Darriwillian - Middle Ordovician). To date, we know that the paleontological register of trilobites found in this quarry is important, not only because of the gigantism achieved by many species but also because of its high level of conservation. For this reason, from a taphonomic and palaeoenvironmental point of view, the protected and anaerobic environment favored the conservation of articulated exuvia near the complete corpses of certain species of trilobites which lived at the limit of their vital possibilities, so that many of these fossils supplemented taxonomic knowledge and highlighted new species. The greatest contribution of this deposit to the biology of trilobites was the discovery of mono and multi-specific associations of the genera Ogyginus, Asaphellus, Ectillaenus, Bathycheilus, Salerocoryphe, Placoparia and Retamapis. The concentration in small spaces of groups of individuals in a similar ontogenic state is interpreted here as an indication of the gregarious behavior achieved by many trilobites during moulting or reproduction. In the vicinity of the mentioned quarry there is, since July 1st, 2006, the Centro de Interpretação Geológica de Canelas (Geological Interpretation Center of Canelas) which brings together some of the most remarkable fossil specimens found here, on the one of the most important geosites of Arouca Geopark and of international importance.