While the stone hammers or pestles with convex bases, which are described on p. 39 et seq. were probably largely used for crushing food and other material; yet some of them and those with concave bases, were undoubtedly sometimes used as hammers for driving wedges, setting stakes, pinning out skins and for similar purposes. _Hammerstones._ The deeply pitted hammer, such as is found in the Mississippi Valley, was not seen here, and it will be remembered[149] that they were not found in the Thompson River region. Tough pebbles, however, were used for pounding. At the quarry shop mentioned on p. 16, we found a number of pebbles that were evidently used in breaking up the material out of which to make chipped implements. One of these (202-8129) is merely a water-worn pebble, 73 mm. long, an edge of which has been broken off, and a sharp corner shows signs of its having been used as a hammer, as it has been battered and shows where one large chip has come off. It will be remembered that in the vicinity of the shop where the specimen was found, pebbles were rarely if ever seen, although the surface of the ground was covered with weathered fragments of volcanic rock. Another specimen (202-8127) found at the same place, shown southeast of the quarry pit, in Fig. 1, Plate III, is 155 mm. long and of a rather irregular cross section. The ends are battered and fractured from use. Apparently it may have been held between the two hands and used in breaking off large pieces of material. A longer hammer pebble, bearing the same catalogue number, and found at the same place, shows on the top of the quarry dump to the left centre in Fig. 1, Plate III. It is about 270 mm. long. In cross section it tends to be triangular with rounded corners. The ends are battered and long slivers have been broken off. The specimen shown in Fig. 40 is from the same place, shorter, but similar in that the section is sub-triangular and that each end is both battered and slivered. Other battered pebbles and fragments slivered from them were found at the same place. The hammerstone shown in Fig. 41 was found on the surface near the head of Priest Rapids. It is an oval pebble, nearly twice as wide as it is thick, of yellowish brown color, which has been used for a hammer, as is indicated by the battered and chipped condition of its ends. [149] Smith, (d), p. 142; (c), pp. 415 and 440, Fig. 38. [Illustration: Fig. 40 (202-8128). Hammerstone. From quarry on north side of Naches River about two miles above its mouth. 1/2 nat. size.]