This latter kind of _dolmen_ more specially assumes the nature of a _tumulus_; a designation which conveys the idea of some mound raised above the tomb. Figs. 134 and 135 represent the _tumulus-dolmen_ existing at Gavr'inis (Oak Island), in Brittany, or, more exactly, in the department of Morbihan. It is the diminished sketch of an enormous model exhibited in the Museum of Saint-Germain. This model in relief has a portion cut off it which, by means of a cord and pulley, can be elevated or lowered at will, thus affording a view of the interior of the _dolmen_. It is composed of a single chamber, leading to which there is a long passage. [Illustration: Fig. 134.--_Tumulus-Dolmen_ at Gavr'inis (Morbihan).] [Illustration: Fig. 135.--A portion of the _Dolmen_ of Gavr'inis.] Were all these _dolmens_ originally covered by earth? This is a question which still remains unsolved. M. Alexandre Bertrand, Director of the Archæological Museum of Saint-Germain, to whom we owe some very remarkable works on the primitive monuments of ancient Gaul, decides it in the affirmative; whilst M. de Bonstetten, a Swiss archæologist of great merit, is of the contrary opinion. The matter, however, is of no very great importance in itself. It is, at all events, an unquestionable fact that certain _dolmens_ which are now uncovered were once buried; for they are noticed to stand in the centre of slightly raised mounds in which the supports are deeply buried. As we before stated, the action of time has destroyed the covering which the pre-historic peoples placed over their sepulchres in order to defend them from the injuries of time and the profanation of man. Thus, all that we now see is the bare stones of the sepulchral chambers--for so long a time supposed to be altars, and ascribed to the religious worship of the Gauls. [Illustration: Fig. 136.--General Form of a covered Passage-Tomb.] In considering, therefore, the _dolmens_ of Brittany, which have been so many times described by antiquarians and made to figure among the number of our historical monuments, we must renounce the idea of looking upon them as symbols of the religion of our ancestors. They can now only be regarded as sepulchral chambers. [Illustration: Fig. 137.--Passage-Tomb at Bagneux, near Saumur.] _Dolmens_ are very numerous in France; much more numerous, indeed, than is generally thought. It used to be the common idea that they existed only in Brittany, and those curious in such matters wondered at the supposed Druidical altars which were so plentifully distributed in this ancient province of France. But Brittany is far from possessing the exclusive privilege of these megalithic constructions. They are found in fifty-eight of the French departments, belonging, for the most part, to the regions of the south and south-west. The department of Finisterre contains 500 of them; Lot, 500; Morbihan, 250; Ardèche, 155; Aveyron, 125; Dordogne, 100; &c.[26]