The implements of stone found in the Celtic grave-mounds, or in their immediate neighbourhood, consist of celts[28] or adzes, hammer-heads or axe-heads, mauls, etc., etc. They are of various materials--chert, shale, green-stone, syenite, basalt, porphyry, felstone, serpentine, sandstone, limestone, etc., etc., and of various degrees of finish and workmanship. Stone celts of one form or other are the most common of all stone implements. In shape they are not inaptly described as being like the mussel shell. The lower, or cutting end is slightly convex, and rubbed down to a fine-shaped edge. As this cutting edge has become dulled or chipped by use it has been again and again rubbed down and sharpened, until, in many instances which have come under my notice, the celt has been shortened fully one-third or more of its original length. The forms of these instruments will be seen in the examples here following (fig. 127 and in the succeeding figures). Fig. 132 is, perhaps, the most usual of these forms. It is of the same type as the first example on the previous engraving. Another excellent example is given on the illustration (fig. 134). It is of chert, and has, as will be seen, straight sides instead of the usual curved ones. It is now 5½ inches long, but has probably originally been much longer, having been rubbed down in sharpening. [Illustration: Fig. 127.] [Illustration: Fig. 128.] [Illustration: Fig. 129.] [Illustration: Fig. 130.] [Illustration: Fig. 131.] [Illustration: Fig. 132.] [Illustration: Fig. 133.] [Illustration: Fig. 134.] [Illustration: Fig. 135.] [Illustration: Fig. 136.] [Illustration: Fig. 137.] [Illustration: Fig. 138.] [Illustration: Fig. 139.] [Illustration: Fig. 140.] [Illustration: Fig. 141.] [Illustration: Fig. 142.] Stone hammers are occasionally found in grave-mounds. They vary much both in form and size, as will be best understood from the following engravings. Fig. 133 was found at Woolaton, and is remarkable for being hollow on its upper and lower surfaces, and ribbed or fluted along its sides. It is eleven inches[29] long, four inches in width, and three inches in thickness. Fig. 135, found at Winster, is thin, very taper, and of very different form. It is ten inches long. Other examples are shown in figs. 136 and 137. Occasionally they partake more of the hatchet shape. A good example is fig. 138, and others of still more elaborate form have occasionally been discovered. Examples of another variety, generally called mauls, which partake more of the common mallet form, are here given on figs. 139, 140, and 141. The first is from Horsley, Derbyshire, and the other two are from Ireland. A different variety (named punches or cutters) is shown on fig. 142, which was found at Mickleover. [Illustration: Fig. 143.] [Illustration: Fig. 144.]