Grotte di Terrassa

Terrassa, a municipality in the Vallès Occidental, has 11 catalogued cavities: 9 pits and 2 caves. Together they total a length of 365 m and reach a maximum depth of 84 m. The recorded lithologies are conglomerates (9), limestones (1) and sandstones (1).

The Avenc de Castellsapera is the longest cavity, at 128 m, and also the deepest, at 84 m; in the Serra de l'Obac it has an entrance 7 by 2 metres, an entrance shaft of 45 metres and a large final chamber, with restricted access from 1 November to 31 May to protect the bat colony. It is followed in length by the Caus del Guitard (83 m), a temporary spring with a narrow, muddy passage, and the Avenc de les Cantarelles (45 m).

Among the deepest cavities are the Avenc de les Cantarelles (37 m), the Avenc de la Serra del Gall (25 m), an old sinkhole of the torrent Maleït, the Caus del Guitard (23 m) and the Avenc de la Serra Llarga (10 m), first explored on 7 April 1912 by members of the Centre Excursionista de Terrassa.