Grotte e abissi nell'unità geologica Zona volcànica d'Olot

The Zona volcànica d'Olot is a unit of the Serralada Transversal formed by 6 cavities, all of them caves. The group totals 405 m of passage and reaches a maximum depth of 19 m. It is a volcanic district of the Garrotxa, where the cavities are linked to lava flows and tubes rather than to karst.

The most notable cavity is the Baumes d'en Caxurma, with 387 m of passage and 19 m of depth; it has been known since time immemorial, with inscriptions more than 100 years old, and has been explored speleologically since the 1940s. The Cova de les Feixes, of 18 m, is a small tunnel in volcanic materials in Olot, the only cavity of this type in Catalonia. The group is completed by the Balma de la Feu, in Santa Pau, 44 m wide and 14 m of maximum depth; the Bauma dels Monjos, also in Santa Pau, 26 m wide and 11 m deep; and the Cova dels Encantats de Dalt, in Sant Joan les Fonts, with two entrances and two galleries that converge inside.

The lithologies present are Sandstone, in 5 cavities, and Basalt, in 1.