The ancient fortress of Ribandelle, of circular form, rises above the Creuse, opposite Châteauvieux. It was successively occupied by the Celts, the Romans, and the Visigoths, but we are unable to fix the date of its erection or the name of the people who built it. There remain but a few ruins at the present day, but we can make out in them the same mode of construction as that followed at Châteauvieux. The walls are faced with unhewn stones, the outer side of which still retains a natural appearance, while the inner is corroded and disintegrated. In the wall itself, separated from the facings by beds of peat mould, are great blocks of vitrified granite. The traces of the action of fire are specially noticeable in the upper part of the walls, so that they were evidently finished when the fusion took place. The site of the furnace in these forts is difficult to determine. It was evidently not situated under any of the blocks, for the earthworks on which they rest retain no traces of the action of fire. Nor was it situated at the side, for the outer facings have retained alike their original form and consistency. Nor can the furnace have been lit on the blocks, as heat exercises its action by radiating in every direction. We are therefore forced to the conclusion that the fire was spread with the aid of spaces left in the inside of the construction at various points, for the vitrified mass is divided into blocks, about nine and three fourths feet long, at very short distances from each other. These few examples will be enough to give some idea of the strange vitrified forts. Many of them retain traces of Roman. occupation. The Guéret Museum possesses a fragment from the Ribandelle walls in which a Roman tile is completely imbedded; and M. Thuot picked up other tiles in a similar condition amongst the ruins. This is a very decided proof that the vitrification took place after the arrival of the conquerors of Gaul. The weapons and tools discovered would appear to confirm this idea, and to suggest similar explanations of vitrification elsewhere. If so, we shall have to admit that vitrified forts date from the earliest centuries of the Christian era, and are not prehistoric at all. We have, however, noticed them here on account of the grave doubts in the matter, and because they furnish a striking and valuable illustration of the relations existing from the most remote tunes between widely separated races, and maintained until the present time. In no other way can we account for the practice of the extremely difficult and complicated operation of the vitrification of bard rocks in districts so far apart as Norway and Scotland, Germany and the midlands of France.