Sir J. Lubbock shares in this opinion, and brings forward facts in its favour. He recites the accounts of various travellers, according to which, the winter-dwellings of certain people in the extreme north bear a very marked resemblance to the "passage-tombs" of the Stone Age. Of this kind are the habitations of the Siberians and the Esquimaux, which are composed of an oval or circular chamber placed a little under the surface of the ground, and completely covered with earth. Sir J. Lubbock thinks, therefore, that in many cases habitations of this kind may have been taken for _tumuli_--a mistake, he adds, all the more likely to be made because some of these mounds, although containing ashes, remains of pottery, and various implements, have not furnished any relics of human bones. In his work on the 'Sépultures de l'Age de la Pierre chez les Parisii,' M. Leguay, a learned architect and member of the Archælogical Society, has called attention to the fact that the construction of these _dolmens_ betrays, as existing in the men of this epoch, a somewhat advanced degree of knowledge of the elements of architecture:-- "The interment of the dead," says M. Leguay, "took place, during the polished-stone epoch, in vaults, or a kind of tomb constructed on the spot, of stones of various thicknesses, generally flat in shape, and not elevated to any very great height, being laid without any kind of cement or mortar. These vaults, which were at first undivided, were subsequently separated into compartments by stones of a similar character, in which compartments bodies were placed in various positions. They were covered with earth or with flat stones, and sometimes we meet with a circular eminence raised over them, formed of a considerable heap of stones which had been subsequently brought thither; this fact was verified by M. Brouillet in 1862 at the _Tombelle de Brioux_ (Vienne). "This kind of interment bears evidence of some real progress. Polished flint instruments are met with intermingled with worked stones which have been brought from a distance. Pottery of a very significant character approaches that of the epoch at which ornamentation commenced; and the _Tombelle de Brioux_ has furnished two vessels with projecting and perforated handles formed in the clay itself. I met with specimens similar to these both in shape and workmanship in the cremation-tombs at Villeneuve-Saint-Georges, which, as I have previously stated, appeared to me to be later in date than the simple interment situated below them.