[2][3] The unit was previously referred to as the "Gres a Dinosauriens", due to the abundant dinosaur remains found in the past.

[4] The Papo Seco Formation (Rey, 1992) marks the return to clastic-dominated sedimentation.

Exposure of the formation is found above the low cliff between Rochadouro and Areia do Mastro, and on the foreshore and beach at Boca do Chapim.

This is interbedded with medium to coarse, commonly ribbon shaped, clastic sandstones.

The exposure clearly shows that the ribbon sands are isolated and change laterally into muds.