The origin and radiation of the first animals.
The Armorican Quartzite hills highlight on the crests of Las Villuercas with their impressive quasi-vertical walls. Armorican quartzite is the old geological denomination to the Ordovician sandstones (orthoquartzite) that are abundant on the west of the Iberian Peninsula. They are undoubtedly the most visible rocks and, also, the most resistant to the erosion. Therefore, they are the testimony of the Ordovician period, near 200 million years older than the Hercynian orogeny that fold them. As they were materials that had been settled on the seabed 480 million years ago they have retained the traces of the trilobites that were plying the sand leaving clues we now call “Cruziana“. These sands became siliceous sandstone which, being pressured by new materials that were deposited on them, performed the dense and compact hard rock known today as Armorican quartzite. During this transformation the fossil traces of the trilobites have not changed and, today, we can see them printed in the rocks almost everywhere. But they are not the trilobites the only fossils found in the geopark, nor the oldest.
Villuercas – Ibores – Jara is also scientifically important for other paleontological deposits whose observation on site is complicated, so it is better to understand them in the interpretation centers.