Dune systems and beaches are scarce on the Cantabrian coast, where the cliffs predominate. In this area is present a very varied morphology (foot of cliff, cove, tombolos, arrows and littoral cordons) some of them very scarce, so its combination acquires great scientific and didactic relevance.

The sandals of Ris and Trengandín are dune laces that constitute the closure of coastal lagoons with a narrow spout that restricts the penetration of the tide. The dune cords are typical of these coastal sands where other dune morphology are also represented: hung dunes (Noja), remontane dunes (Berria, Joyel), blowouts (Laredo, Noja).

In Ris, there is also a small tombolo that connects the islet of the sea liberated by the combination of the karstic and marine processes.

A tombolo of much larger size is that of Berria which connects with earth Buciero Mount. It has a very unique origin because it has not been generated by the refraction and diffraction of the waves, but by combination of the coastal current and the dominant waves of the northwest.

The Puntal of Laredo is an arrow formed by the refraction of the swell by overcoming the tombolo formed by Buciero Mount. The wave induced local drift movement that transports the sediments in the same direction contributes to the formation of the sandy strut in contact with the estuarine currents.

As far as the dune fields are concerned, they constitute an important reserve of sand during the storms, being significant therefore their role as protectors of the coast (ecosystem service of regulation).