112 BUREAU OF AMERICAN ETHNOLOGY [Bull. 189 



Asymmetrical knives (10 specimens) : 



The form of these specimens is best shown in the illustration (fig. 

 18, h). They have one strongly convex edge, and one edge more 

 nearly straight. The ends are convex to pointed. The three com- 

 plete specimens are 77 to 102 mm. long, 36 to 55 mm. wide, and 8 to 11 

 mm. thick. Materials are chert and quartzite. 



Vein chalcedony knives (45 specimens) : 



These knives were made from slabs of vein chalcedony, one or more 

 edges of which were bifacially flaked to form a sharp cutting edge. 

 They are 20 to 80 mm. long, 15 to 67 mm. wide, and 5 to 10 mm. tliick 

 (fig. 18,^). 



Flake knives (39 specimens) : 



Flakes with bifacial flaking on one or more edges are classed as flake 

 knives. The edge is generally even and regular, with carefully de- 

 tached pressure flakes forming the cutting edge. Flakes are of almost 

 every shape, with lengtlis up to 102 mm. Materials are quartzite, 

 petrified wood, and chalcedony. 



Flake scra'pers (154 specimens) : 



Flakes with regular, unifacial pressure flaking along one or more 

 edges are classed as flake scrapers. These tools were made from con- 

 choidal flakes of Knife River chalcedony, quartzite, colored chert, 

 petrified wood, and a few pieces of stone which resemble Bijou Hills 

 quartzite. This stone, common in sites along the Missouri River in 

 southern South Dakota and northeastern Nebraska, may have been 

 traded into the area. 



Modified flakes (170 specimens) : 



Flakes of varying size and form, having one or more edges bearing 

 minute flakes detached by use, are classed as modified flakes. These 

 flakes appear to have been modified by use and not by pressure flaking. 

 Material is chalcedony, petrified wood, chert. Knife River chalcedony, 

 and quartzite. A single flake of smoky obsidian (the only scrap of this 

 material recovered at the site) resembles samples from Wyoming. 



Choppers (19 specimens) : 



Circular or oval slabs of quartzite, chert, and basalt, detached from 

 the parent material by percussion, may have been used as choppers. 

 Most of them have convex to straight edges modified by coarse, uni- 

 facial percussion flaking, although some of them are bifacially flaked. 

 These implements are large, measuring 90 to 260 mm. long and 55 to 

 30 nrni. wide. One of them has shallow notches flaked into the edges 

 and could have been haf ted for use as an ax. 



