been a gap in nature, that, because of the ice age, man had retreated from Europe. The information must now be found. In 1895 Édouard Piette stated that he had heard Édouard Lartet speak of "the remains from the intermediate period (les vestiges de l'époque intermédiaire)", which were yet to be discovered, but Lartet had not published this view. The gap had become a transition. However, asserted Piette: I was fortunate to discover the remains of that unknown time which separated the Magdalenian age from that of polished stone axes ... it was, at Mas-d'Azil in 1887 and 1888 when I made this discovery. He had excavated the type site of the Azilian Culture, the basis of today's Mesolithic. He found it sandwiched between the Magdalenian and the Neolithic. The tools were like those of the Danish kitchen-middens, termed the Surface Period by Evans, which were the basis of Westropp's Mesolithic. They were Mode 5 stone tools, or microliths. He mentions neither Westropp nor the Mesolithic, however. For him this was a "solution of continuity (solution de continuité)" To it he assigns the semi-domestication of dog, horse, cow, etc., which "greatly facilitated the work of Neolithic man (a beaucoup facilité la tàche de l'homme néolithique)." Brown in 1892 does not mention Mas-d'Azil. He refers to the "transition or 'Mesolithic' forms" but to him these are "rough hewn axes chipped over the entire surface" mentioned by Evans as the earliest of the Neolithic. Where Piette believed he had discovered something new, Brown wanted to break out known tools considered Neolithic. The Epipaleolithic and Protoneolithic of Stjerna and Obermaier Sir John Evans never changed his mind, giving rise to a dichotomous view of the Mesolithic and a multiplication of confusing terms. On the continent, all seemed settled: there was a distinct Mesolithic with its own tools and both tools and customs were transitional to the Neolithic. Then in 1910, the Swedish archaeologist, Knut Stjerna, addressed another problem of the Three-Age System: although a culture was predominantly classified as one period, it might contain material that was the same as or like that of another. His example was the Gallery grave Period of Scandinavia. It was not uniformly Neolithic, but contained some objects of bronze and more importantly to him three different subcultures. One of these "civilisations" (sub-cultures) located in the north and east of Scandinavia was rather different, featuring but few gallery