The causes why the nuclei were rejected as useless are still susceptible of being traced. In some cases they had become so thin that they would not bear re-shaping; in others a want of |29| uniformity in the texture of the flint, probably caused by some included organism, had made its appearance, and caused the flakes to break off short of their proper length, or had even made it useless to attempt to strike them off. In some rare instances, when the striking off long flakes had proved unsuccessful on the one face, the attempt has been made to procure them from the other. The abundance of large masses of flint near Pressigny—some as much as two or three feet across—has, however, rendered the workmen rather prodigal of their materials. The skill which has been brought to bear in the manufacture of these long flakes is marvellous, as the utmost precision is required in giving the blow by which they are produced. Generally speaking, the projecting ridge left at the butt-end of the nucleus between the depressions, whence two of the short flakes have been struck off in chipping it square, has been selected as the point of impact. They appear to me to have been struck off by a free blow, and not by the intervention of a set or punch. No doubt the face of the flint at the time of the blow being struck was supported on some elastic body. A few flints which bear marks of having been used as hammer-stones are found at Pressigny. |30| [Illustration: Fig. 3.—Nucleus—Pressigny. 1∕2] [Illustration: Fig. 4, Fig. 5; Nuclei—Pressigny. 1∕2] An interesting lecture on the Flint Industry of Touraine was given on the occasion of the annual meeting of the Société Archéologique de Touraine, in 1891, by M. J. de Saint-Venant. |31| [Illustration: Fig. 6.—Flake—Pressigny. 1∕2] [Illustration: Fig. 7.—Flake—Pressigny. 1∕2]