The fossil tracks we find in Santa Cruz de Yanguas were made by ornithopods who left them in parallel impressions of 6 or 7 imprints. These are animals who lived between 130 and 150 million years ago, marked on the rock in bas-reliefs measuring 20-35 centimeters.  The visitor will also find at the site a replica of one possible producer of those fossil tracks: Stegosaurus.

Other fossil track trails close to Santa Cruz de Yanguas can be found in the wilderness areas of Valdecantos, Las Cuestas and Prado Caído.

The ornithopods were more social dinosaurs (they moved around in packs), had very specialized teeth for grinding vegetation, and a powerful tail used for defensive purposes. One curious feature of these animals is that they walked on two legs when they were young, but on four as full adults. Their tracks were tridactyl, similar to those of the theropods (when the fourth toe did not make an impression), but were wider in relation to their length, since they had paws instead of claws.