Grotte della Vallès Oriental

The Vallès Oriental contains 37 inventoried cavities: 29 caves and 8 pits, with a total length of 1096 m and a maximum depth of 29 m. The comarca has 11 child units. Among the lithologies represented are limestones (17), travertines (8), sandstones (5), marbles (3), conglomerates (2) and granites (2).

The Cova dels Ermitans, at the Farell (Caldes de Montbui), at the Serrat d'en Vila, beside the torrent del Farell, is the longest cavity, with 287 m of length, and the deepest, with 29 m. It has three entrances, a total drop of 28.7 m (+9.3; -19.4) and 286.8 m surveyed. Other cavities notable for their length are the Cova del Bon Pastor (120 m), at the tosques de Sant Miquel del Fai, also called Cova de Sant Martí; the Cova de l'Home Mort (78 m), at la Garriga, also known as Cova de Can Plans de Monteugues, Cova dels Pirates, Cova de la Granota and Cova de l'Home Mort; the Cova de Sant Miquel del Fai (60 m), a small tourist cave with a single illuminated gallery and a small pool at the end; and the Balma del Ca (45 m), at Sant Feliu de Codines, with stalagmitic masses at the entrance and remains from the Middle Palaeolithic.

As for depth, after the Cova dels Ermitans (29 m) come the Cova del Bon Pastor (22 m); the Avenc d'en Toni (14 m), at the Sot de Bac (el Figaró), discovered in 1975 by the SIRE – UEC and revisited in 2016 by the grup de l'espeleodijous; the Forat Nº2 de les Pedreres (14 m), at Gualba, with an entrance in the form of a small cave, a 7.40 m shaft and a hall with walls of marbles and granite; and the Cova de l'Infern (13 m), with 42 m of length at the Montseny (Aiguafreda), with an internal route of conduits, shafts and galleries on a slope.