MOUNDS IN IOWA AND WISCONSIN. 



601 



MetJiod of flint- chipping. — Some years ago Dr. Knapp, while making a 

 reconnaissance of "■ Twelve-mile Island,'' in the Mississippi near Gutten- 

 berg, Iowa, made the acquaintance of a roving baud of the Pottawatomie 

 Indians who were encamped for the time on this island. While among 

 them he witnessed the process of flint arrow-point manufacturing as 

 carried on by this band, and as the writer has not observed a descrip- 

 tion of this process in print before, a short account of it is here given. 



A tree from 12 to 20 inches in diameter was selected and a large 

 notch or cavity 6 inches in depth was made in one side of the trunk at 

 a sufficient distance from the ground to allow of a person occu])ying a 

 sitting posture on the ground to work this "instrument" with facility. 

 The upper portion or roof of this cavity sloped obliquely downward ; 

 the farther side was perpendicular and the bottom horizontal. On the 

 bottom of this cavity a small even slab of rock of some hard material 

 was placed. A short distance above this rock a small hole or notch 

 was made in the farther side of the cavity. Into this notch was in- 

 serted the "leg bone of a deer," and under this was placed, edgewise 

 and resting on the basal rock below, the piece of stone to be wrought, 

 this possessing the quality of conchoidal fracture. The implement was 

 then deftly worked out by pressure of the carefully manipulated cylin- 

 drical bone. 



The size of the instrument to be wrought was regulated by moving 

 the specimen farther from or near to the outer margin of the basal rock. 



This description may be further illustrated by the following cut (Fig. 

 9) from a rude sketch of the " instrument" made by Dr. Knapp: 



Fig. 9. — (a) Cavity cut in the tree,; {b) cyliudrical boue of " deer'a leg; " (c) stone 

 to be wrought ; (rf) basal stoue. 



