84. BUREAU OF AMERICAN ETHNOLOGY [Bull. 177 
Oo 256M 
Ficure 28.—Stone tools from the Mabaruma Phase. a-—b, Flake blades or knives. ¢, Hoe. 
d, Polishing stone. ¢, Polished knife. 
Metate (fig. 29, a-b).—Two fragments of granite with one surface 
well smoothed and slightly concave were probably used for grinding. 
They measure 7.5 by 7.5 by 2.0 to 3.0 cm. thick and 7.0 by 11.2 by 3.2 
cm. The grinding surface in each case is slightly smaller than the 
surface of the fragment. The contours do not suggest that the com- 
plete artifact was very large. 
Polishing stones (fig. 28, d)—Small, waterworn pebbles of quartz 
and fine-grained micaceous schist have been used for polishing stones. 
The particular type of wear suggests they probably were used as pol- 
ishers in pottery making. The roughly oval pebbles measure 2.4 by 
2.7 by 2.0 cm., 3.0 by 2.4 by 14 cm., and 5.8 by 2.4 by 0.8 cm. The 
