There is an abundance of distinctive Nummulites fossils scattered over the Dineretes hill. These organisms lived in the Eocene period (55 to 33 million years ago) when this region was submerged beneath the sea. It is possible to make out a disc-shaped shell, made up of several layers to make a flat spiral. They owe their name to the discoidal shape, similar to that of a coin; nummus is latin for coin and lithos is Greek for rock. Locally they are known as “dineretes” or “little coins.” Other fossils (such as alveolinas, assilinas, operculinas, cidaris) are often found in this same area.

The N-123 road that heads north from Barbastro runs parallel with this magnificent gorge, which reaches a depth of 300m. It was formed by the erosion of the limestone of the north face of the Carrodilla mountain range by the power of the River Ésera. The karst effect has created a number of caves, such as the Moro cave, where evidence of human activity from the Bronze Age can be seen.

See LIC Congosto de Olvena

Impressive rock “pleats” that are found in the Alcanadre Canyon, at the end of the area known as Gorgas Negras and at the beginning of the Barrasil Canyon. They are the result of Alpine orogeny.

La geología es la ciencia que estudia el origen, formación, evolución, composición y estructura interna de la Tierra, y los procesos por los cuales ha ido evolucionando a lo largo del tiempo geológico.

Guara Somontano ofrece una lección magistral de cómo se ha formado el paisaje que vemos: recorriéndolo descubriremos los procesos geológicos que explican por qué hay montañas y valles, barrancos y mallos, muelas y acantilados...