SMITHSONIAN AECH^OLOGICAL COLLECTIOK. 



11 



a. Triangular or more or less convex-sided, sometimes very slender; base 

 straight (Fig. 26, light-gray chalcedony, Tennessee), concave (Fig. 27, 

 yellow jasper, California), or convex, in some cases bluntly pointed. 



SPEAE-HEADS. 



b. Notched at the sides near the base, the latter being straight, concave, or 

 convex (Fig. 28, gray flint, Kentucky). Barbs are sometimes formed by 



