Les impressionnants bancs de micaschistes à grenats, qui s'enfoncent ici sous la mer, sont inclus dans une réserve naturelle minéralogique. Il est absolument interdit d'échantillonner. Seule la mer a le droit de tout casser, et ne s'en prive pas.
The impressive micaschist benches with garnets, which sink here into the sea, are included in a mineralogical natural reserve. Sampling is absolutely prohibited. Waves only have the right to break, and do not refrain.

Micaschist outcrops at Pen Ganol. The colour varies from golden to silvery. These rocks of the eastern part of the island were formed at 50-60km deep, while the western end displays layers matured at 45-55km deep. The return to surface occured 360-350My ago. The numerous garnets give its red colour to the sand of the Sables Rouges area.

Nucella lapillus (Linnæus 1758) in a crevice, near mussels, its favourite dish. The red anemona is an Actinia equina (Linnæus 1758), the Beadlet anemone, which can live more than 60 years. This is a night hunter.

The Phare des Chats, on the southeastern end of the island. It announces the danger caused by the rock benches that advance in the sea on almost one kilometer (Basse des Chats, Plateau des Birvideaux). Nota bene that these Chats are a vernacular name for stone, and refer to the old word Chaillou, which gave Caille, Chaillot, Caillou and, also, these cats.

The Pointe des Chats, pictured from Locqueltas cliffs, during a summer storm. All the grounds on the image, underwater or not, belong to the mineralogical reserve. The green beacon of Bézelec announces the access to the bay of Locmaria.