It is generally recognised by students of prehistory that, with the close of Acheulean times, a new method of flint implement-making came into vogue. The Acheulean implements which are found in various ancient valley gravels and other deposits represent the culmination of the long-continued coup de poing or hand-axe industry, in which the well-known pointed and oval palæolithic implements were made. These specimens were produced by so modifying a nodule of flint, by the removal of flakes, that the implement, in its final form, represented the core or central portion of the original nodule.