Grottes de Nichet

V. THE GROTTE DE NICHET.

The most marvellous geological curiosity in the Ardennes is undoubtedly the Grotte de Nichet, carved out of the Givet limestone which, about 3 kilometres long, crosses French territory at the northern tip of the department and continues into Belgium for a length of at least twelve leagues.

These limestone banks, which run almost parallel to the railway line for a length of 300 metres, form an angle of 110 degrees with the compass needle, whereas in the Charlemont tunnel, the banks form an angle of 25 degrees with the compass needle and are almost perpendicular to the railway line A similar layout of the limestone banks, but in the opposite direction, is found to the south of the village of Fromelennes, and the banks appear to meet at the Nichet cave. From the top of the hill, where the entrance to the cave is located, you can see the limestone banks coming from the direction of Flohimont and Rancennes plunging southwards, while those coming from Fromelennes, which are clearly visible at the place known as La Cote, opposite the Donau marble sawmill, plunge eastwards at a much shallower angle.

It therefore seems likely to us that the Nichet cave originated in a void that formed as a result of a difference in the inclination of the banks where they meet after they were broken and uplifted. In this void, a series of boulders crumbled together, taking up different positions and intertwining, thus subdividing the space between the banks into chambers, galleries and corridors, whose walls were covered by limestone deposits carried along by rainwater, which at the time must have fallen in abundance at fairly high temperatures, easily dissolving the limestone near the outer surface. The surface area occupied by the galleries, which are now merged, is 100 metres long and 70 metres wide. They are no more than 25 metres deep, but as no water has been deposited in the lowest parts of the cave, we can only conclude that the water from the seepage is flowing through galleries that have not yet been identified and which are at great depth. As the rainwater penetrates through the interstices, it becomes loaded with limestone. It then falls, drop by drop, onto the fallen blocks, forming stalagmites or welding the blocks together, causing some of them to lose their original shape. (See Watrin in the Bulletin de la Sociéré d'Histoire naturelle des Ardennes: La Grotte de Nichet).

Until 1894, the cave was virtually abandoned. However, as the entrance remained free, a few visitors, candles or torches in hand, ventured into the more remote galleries and, in order to find their way easily, they tied the end of a rope near the entrance, which they unwound as they progressed through the galleries. The visit was quite arduous. The paths, which were almost impassable, were made very slippery by the limestone-laden water, which fell drop by drop from the galleries, forming stalactites and stalagmites in some places, some of which eventually came together. You passed over steeply sloping blocks where there was nothing to hold you back. The foxes took refuge in some of the galleries where, as proof of their habitual stay, they left their bones. The bats were grouped together in the first room. When the cave was officially opened, they were found stuck to the ceiling.