Text written in Basque and translated automatically by Elia without any subsequent editing. SEE ORIGINAL

Fossils, stone souvenirs

A shallow warm sea covered part of the current Basque Country in the Cretaceous. Large reefs were formed by the accumulation of calcium carbonate, the main component of its inhabitants, from which comes the limestone found in Aizkorri, Aralar, Anboto, Gorbea or Valderejo. And that's why there are marine fossils on these peaks.