Access coming from:

- Alcanena (± 20.5 km) by N361, 25 de Abril street and Principal street to S. Bento. There, take the dirt road to Casal Velho / Azelha for 2.7 km. The depression is on the left with access only on foot.

- Porto de Mós (± 20.5 km) by N362 to Serro Ventoso. There, follow to Pebada street and Principal street to Casal de Santo António street to Azelha.

GPS: 39.519683, -8.816740

In the central sector of the Sto António plateau, in the hills of S. Bento, where nature favored the karst, the depression of Cós Carvalho presents a great didactic value. Between its bottom and its sides can be observed an interesting limestone pavement resulting from the dissolution process of calcareous rocks. The subsequent evolution is marked in the karst exposed by dissolving process due to run-off water. Thus, in the depression of Cós Carvalho can be seen he ruiniform aspect of a paleokarst, aesthetically appealing, formed by a set of lapiaz or karren fields of various dimensions, witnesses of a long and gradual opening of cracks formed by dissolution, from the network of diaclases under cover.

On top of these clints can be observed dissolution wells formed under cover, whose origin can be associated to the direct action of plant roots, dissolving small basins, small elements, predominantly of biochemical origin, and of erosion cannelures.

Depression – landform sunken or depressed below the surrounding area.

Diaclase – fracture of a rock without movement.

Karst - A distinctive topography that indicates dissolution of underlying soluble rocks by surface or ground water in areas of easily soluble rocks. Characterized by caves, underground drainage and sinkholes.

Lapiaz or karren field - common landscape in limestone areas, with many grooves due to the dissolution of limestone by rainwater along fractures and cracks.