The inner, or flat face of a flake, is that produced by the blow which dislodged it from the parent block, core, or nucleus. The outer, ridged or convex face comprises the other facets, or, in some instances, the natural surface of the flint. The base, or butt-end of a flake, is that at which the blows to form it were administered; the other end is the point. Flakes may be subdivided into— 1. External, or those which have been struck off by a single blow from the outer surface of a nodule of flint. Many of these are as symmetrical as those resulting from a more complicated process of manufacture, and they have frequently been utilized, especially for scrapers. 2. Ridged flakes, or those presenting a triangular section. One face of these sometimes presents the external crust of the flint, as in Fig. 190. In others, the ridge has been formed by transverse |276| chipping, as is the case with the long flakes from Pressigny (Fig. 6), but this method appears to have been almost unknown in Britain. 3. Flat, where the external face is nearly parallel to the internal, and the two edges are formed by narrow facets, as in Fig. 200. 4. Polygonal, where the external face consists of many facets, as in Fig. 192. These several varieties may be long or short, broad or narrow, straight or curved, thick or thin, pointed or obtuse. The character of the base may also vary, being rounded or flat, thick or thin, broad or narrow. The cores from which flakes have been struck are, of course, of various forms, some having had only one or two flakes removed from them, and others several. In the latter case they are often more or less regularly polygonal, though only few of the facets will be of the full breadth of the flakes, as the external face of every successive flake carries off some part of the traces of those previously struck off. Not unfrequently some of the facets are arrested at a little distance from the end where the blows were struck, in consequence of the flake having broken short off, instead of the fissure continuing to the end of the block. Occasionally, and more especially on the Yorkshire Wolds, the nuclei are very small, and much resemble in character those found, with numerous flakes, in India, in the neighbourhood of Jubbulpore.[1165] It has been suggested[1166] that cores were occasionally made on purpose for use as tools; but this appears very doubtful. Of course, if a core were at hand, and seemed capable of serving some special purpose, it would be utilized. [Illustration: Fig. 189.—Weaverthorpe. 1∕1] * * * * *