Grotte e abissi nell'unità geologica Collserola - Pla de Barcelona

The Collserola - Pla de Barcelona unit, within the Serralada Litoral, brings together 6 cavities, all of them caves, with a total passage of 608 metres and a maximum depth of 20 metres. The materials are diverse, with the presence of Limestone and Conglomerate, and small cavities between slates and limestones.

The longest cavity is Escletxes de Papiol, with 300 metres, also the deepest with 20 metres. It is followed by the Coves de Santa Creu d'olorda, with 206 metres of surveyed passage and a maximum vertical range of 14 metres, and the Cova de la Torre Negra, of 76 metres, known since 1964 and with an important assemblage of Neolithic burials. The Cova Petita de la Torre Negra, of 16 metres, explored on 14 February 1988, and the Cova Penjada de la Torre Negra, of 5 metres, complete the group.