One of the types which is most extensively distributed, especially in the drift beds of the valley of the Somme, where scarcely any other kind is found, is the _almond-shaped_ type (fig. 10). [Illustration: Fig. 10.--Hatchet of the _Almond-shaped_ type, from the Valley of the Somme.] The instruments of this kind are hatchets of an oval shape, more or less elongated, generally flattened on both sides, but sometimes only on one, carefully chipped all over their surface so as to present a cutting edge. The workmen of the Somme give them the graphic name of _cats' tongues_. They vary much in size, but are generally about six inches long by three wide, although some are met with which are much larger. The Pre-historic Gallery in the Universal Exposition of 1867, contained one found at Saint-Acheul, and exhibited by M. Robert, which measured eleven inches in length by five in width. This remarkable specimen is represented in fig. 11. [Illustration: Fig. 11.--Flint Hatchet from Saint-Acheul of the so-called _Almond-shaped type_.] Another very characteristic form is that which is called the _Moustier type_ (fig. 12), because they have been found in abundance in the beds in the locality of Moustier, which forms a portion of the department of Dordogne. This name is applied to the pointed flints which are only wrought on one side, the other face being completely plain. [Illustration: Fig. 12.--Wrought Flint (_Moustier type_).] To the same deposit also belongs the flint _scraper_, the sharp edge of which forms the arc of a circle, the opposite side being of some considerable thickness so as to afford a grasp to the hand of the operator. [Illustration: Fig. 13.--Flint Scraper.] Some of these instruments (fig. 13) are finely toothed all along their sharp edge; they were evidently used for the same purposes as our saws. [Illustration: Fig. 14.--Flint Knife, found at Menchecourt, near Abbeville.] The third type (fig. 14) is that of _knives_. They are thin and narrow tongue-shaped flakes, cleft off from the lump of flint at one blow. When one of the ends is chipped to a point, these knives become scratchers. Sometimes these flints are found to be wrought so as to do service as augers. The question is often asked, how these primitive men were able to manufacture their weapons, implements, and utensils, on uniform models, without the help of metallic hammers. This idea has, indeed, been brought forward as an argument against those who contend for the existence of quaternary man. Mr. Evans, an English geologist, replied most successfully to this objection by a very simple experiment. He took a pebble and fixed it in a wooden handle; having thus manufactured a stone hammer, he made use of it to chip a flint little by little, until he had succeeded in producing an oval hatchet similar to the ancient one which he had before him.