may have been used as a pestle. Simple short cylindrical or conoid pebbles, only slightly changed from their natural form, are used for pestles in the Nez Perce region to the east.[90] [90] Cf. Spinden, Figs. 1-4, and 8, Plate VIII. A pebble 559 mm. long by 152 mm. wide and 114 mm. thick, with rounded corners and ends, found by Mr. John Lacy near the Yakima River in North Yakima, has longitudinal grooves pecked in three sides to where they begin to round over to form the end, and a similar groove, except that it is only about 101 mm. long, in the middle of the fourth side.[91] These grooves were probably made as part of a process of grooving and battering down the intervening ridges in order to bring the specimen into a desired form. Similarly grooved pebbles found on the northern part of Vancouver Island were explained to Professor Franz Boas as having been implements in such process of manufacture. So far as I am aware, Prof. Boas' announcement of this at a meeting of the American Association for the Advancement of Science was the first explanation of the sort of grooving or fluting of specimens found in northwestern America. One similar large specimen (20.0-3343) found at Lewiston, Idaho, in the Nez Perce region by Dr. H. J. Spinden, bears two longitudinally pecked grooves in addition to pecking on much of its surface. A yellowish gray boulder about 349 mm. long, nearly circular in sections and with rounded ends, from Priest Rapids, bears a pecked groove 82 mm. long by 31 mm. wide and 6 mm. deep across the middle of one side. This may have been made to cut it into the length desired for a pestle.[92] This specimen is much too large to be considered as the handle of a digging stick, similar to the object from the Nez Perce region considered as such by Spinden.[93] [91] In the collection of Mr. Janeck and Museum negative nos. 44453, 2-2 and 44501, 6-2. [92] In the collection of Mr. Mires, and Museum negative no. 44534, 8-12. [93] Cf. Spinden, Plate VII, Fig. 33. [Illustration: Fig. 21 (202-8281). Pestle made of Stone. From the surface, near the head of Priest Rapids. 1/2 nat. size.] [Illustration: Fig. 22 (202-8263). Pestle pecked from Stone. Probably unfinished. From the surface, near the head of Priest Rapids. 1/4 nat. size.] [Illustration: Fig. 23 (202-8399). Pestle pecked from Stone. Probably unfinished. From the surface, eight miles above the head of Priest Rapids. 1/2 nat. size.]