The stream of L’Om or La Baga Cerdana is a tributary going down from the Moianès plateau, from the area of the country houses of La Grossa (Calders) and La Moratona (Moià), to join the stream of La Golarda or Marfà on the gangway of Palanca de La Coma (Monistrol de Calders). The stream of La Baga Cerdana uses to have water all along the year, though not that much. In the surroundings of the house of La Coma, in the area named Baga Cerdana, the stream jumps spectacularly in the center of a large cirque-shaped rock shelter, at least 15 meters high by 30-40 meters diameter. Beneath it, there is a pool of clear, clean water where aquatic plants such as Alisma lanceolatum and Groenlandia densa can live. The place keeps the humidity and freshness, as well as a primeval beauty.
The shelter results from the differential erosion of the stream on the marine sedimentary rock in horizontal strata of variable resistance. Top down, we can see conglomerate in the highest stratum, limestone in the stratum that stands out in the middle of the wall and sandstone below, the weakest stratum. Many sandstone slabs have fallen from the ceiling, some of them showing on their surface the waves of the sand from the time when it laid down in a very shallow sea. These fossil waves on sandstones are internationally known in Geology as ripple marks.
In the 2nd image, the ICHN-Bages group at the waterfall of La Baga Cerdana during the naturalist outing to the valley of Marfà on 25.05.2024.
[photos Jordi Badia]