32 



ANCIENT AKT OF THK PROVINCE OF CHIRIQUI. 



surface. Till' surfaces arc souicwliat whitened fioni (lecoinijosition, 

 but within the mck Ism-arly hiack, ■■uid thce^eiouhl not (hstmguish 



it from a dark slate. The material is shown by microscopic test to 

 l)e a v()lcanic tufa. These examples were evidently intended for more 



delicate work than the preceding. The shapes of the specimens 

 illustrated in Figs. 21 and 23 indicate a still different use. The upper 



