The Fuente Lacorte-El Frontal site (actually two sites grouped together) is located some 200 meters from Bretún. There is a small parking lot for small cars in the immediate vicinity, and a bigger one for public transport next to the Bretún Church 150 meters away.

The site dates from the early Cretaceous and contains one of the largest amounts of fossil tracks recorded in the area. All of them were made by large and small theropods, or by ornithopods, and some are grouped in trails of up to 11 tracks.  In addition, it has a spectacular life size replica of an allosaurus, one of the dinosaurs that could have inhabited this part of Soria 150 million years ago.

The theropods were a group of predatory dinosaurs. They had two long, strong back legs that enabled them to run at high speeds. Their front legs were short and boasted very sharp claws. Their heads featured very strong jaws with sharp teeth. When this group of dinosaurs first appeared its members were shorter and lighter. Over time they kept gaining in strength, weight and power, albeit losing some speed, which enabled them to hunt large prey. Their fossil tracks are normally tridactyl, although they can give the impression of a fourth toe. Even though the fossil tracks can be confused with ornithopods, their width is frequently smaller in relation to the length.

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 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.