Le souterrain de la Roche Trocante

Superb underground passage dug into the clay. A shaft and two chambers are visible. This cave is of undetermined date. There are both modern and possibly ancient engravings on the walls.

"There is a gap of about 1,200 metres across an arid plain where gorse and heather grow at leisure. Then, on the left, there is a hawthorn hedge so high that it resembles an avenue; at the corner of this arboreal hedge is a cross, on the edge of a small path that runs alongside a vineyard. Follow this path across the entire width of the vineyard, then go up at right angles along the edge of the vineyard. You will soon discover a few small excavations, then the entrance to the underground passageway facing south. The woods of the de la Meule estate stretch out nearby.

The opening of the cave is very low and you have to crawl to get into the passage; it gradually increases in height and reaches a height of 1.90 m towards the bottom. The overall shape of the underground passage is that of a T, with the central shaft measuring 7.80m long and 2.10m wide where it meets the crypt at the bottom. This extends further to the west than to the east. The vault to the west measures 1.90 m by 2.20 m; the vault to the east is 84 cm deep by around 2 m.

It is an ancient sepulchral cave from the Dolmenic period, and its shape and dimensions are more or less the same as those of our covered walkways. Tombs of this type, which are very rare in our granite regions, are well known in certain limestone regions, and the fine work of Baron de Baye has provided us with some very curious specimens.


Source: Dictionnaire archéologique de la Loire-Inférieure by Pitre de Lisle du Dreneuc published in the Bulletin de la Société d'archéologie de Nantes et du département de Loire-Inférieure, 1st half of 1885.