Rock type: carbonate sedimentary.

Age: about 70 million years. Cretaceous period (Maastrichtian).

Characteristics: composed of a muddy calcareous matrix and carbonaceous grains of sand, including fossil fragments of mollusks shells and other organisms, and traces of the activity of organisms are preserved (bioturbation).

Formation environment: coastal areas.

Uses: construction material and to build riprap.

Origin of the block: north flank of Montsec (Pallars Jussà).