edges. On the other hand, should a few caves and rock-shelters in one or two favourite localities continue to be inhabited after the arrival of the Neolithic tribes on the scene there might be few traces of amalgamation to be found. Such points of contact have, however, been discovered in more recent times in various parts of the European Continent. It is on the validity of the evidence furnished by these transition stations that the hiatus problem must be finally solved. Stations with undisturbed and successive strata containing remains of the two civilisations are now so numerous that only a few of the more important can be here considered.
(1) The Cavern of Mas-d'Azil.
The late M. Ed. Piette was one of the most strenuous advocates of the existence of a transition period, evidence of which he had obtained in several caves and rock-shelters situated in the south-west of France among the rocky regions to the north of the Pyrenees, the most important of which is the Cavern of Mas-d'Azil (Ariège). This is a vast subterranean gallery about 400 metres in length, at the bottom of which foams the turbulent waters of the Arise. During the construction of a road along the stream the relic-bearing deposits were discovered. M. Piette, who commenced the systematic excavation of the cave in 1887, recognised two sites of habitation by man, one about the middle of the cave on the right of the Arise, and the other near the entrance on its left. A résumé of his researches on this site was brought before the loth Congress of Anthropology and Prehistoric archæology held in Paris (1889), with the result that there was a consensus of opinion among the members that his discoveries proved that the interval between the two civilisations in that locality had been of short duration. Some of the more remarkable relics were exhibited at the meeting, where I had an opportunity of inspecting them. Subsequently (1895) M. Piette published a more detailed account of the structure and contents of the stratigraphical deposits at the entrance to the cave and on the left bank of the Arise (L'Anth., vols. vi. and vii.), of which I subjoin a brief outline.
Above a stratum containing relics characteristic of the
