That this bed was formed by action of glaciers is shown, not only from the well-rounded tertiary pebbles, but also from the great blocks of hard sandstone, some of which are over four feet in diameter. These large fragments not only abound at St. Acheul in both the higher and lower level gravels at Amiens, and at the higher level at Abbeville, but they are also traced far up the valley wherever the old diluvium occurs. All of these sandstones have been derived from the tertiary strata which once covered the chalk. [Illustration: FIG. 6. FLINT IMPLEMENT FROM ABBEVILLE. _a._ Oval-shaped flint hatchet from Mautort near Abbeville, half size of original, which is five and a half inches long, from a bed of gravel underlying the fluvio-marine stratum. _b._ Same seen edgewise. _c._ Shows a recent fracture of the edge of the same at the point _a_, or near the top. This portion of the tool, _c_, is drawn of the natural size, the black central part being the unaltered flint, the white outer coating, the layer which has been formed by discoloration or bleaching since the tool was first made. The entire surface of Figure 6 must have been black when first shaped, and the bleaching to such a depth must have been the work of time, whether produced by exposure to the sun and air before it was imbedded, or afterward when it lay deep in the soil.--_Antiquity of Man._] As the flint implements of Abbeville and Amiens are the same as those of St. Acheul, and from the same beds, what has already been said will apply to them. These implements have been found in these localities in great numbers, as several thousand of them already taken from the beds will amply testify. From the gravel-pit in which were found the flint axes, at Abbeville, and close to the ancient chalk, was taken the celebrated human bone known as the _jaw_ of Moulin-Quignon. It was cotemporary with the axes, and undoubtedly some of the flint implements there found were fashioned by the man of whom that jaw formed so necessary a part. This jaw-bone belonged to an old man, and is described as displaying "a tendency toward the animal structure in the shortness and breadth of the ascending ramus (the perpendicular portion of the lower jaw), the equal height of the two apophyses (a process or regular prominence forming a continuous part of the body of the bone), the indication of prognathism (projecting jaw) furnished by the very obtuse angle at which the ramus joins the body of the bone.[14] Near the same locality other human bones were discovered Which presented the same characteristics.