Apparently prehistoric man was hunting big game with stone tools one year and farming with domestic animals and ground stone tools the next. Mortillet postulated a "time then unknown ("époque alors inconnue")" to fill the gap. The hunt for the "unknown" was on. On 16 April 1874, Mortillet retracted. "That hiatus is not real ("Cet hiatus n'est pas réel")," he said before the "Société d'Anthropologie", asserting that it was an informational gap only. The other theory had 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: