hated ty ARCHEOLOGY IN BRITISH GUIANA 47 
Percussion flake picks of the large variety range from 5-10 cm. in 
length, 2.5-5.0 em. in width, and 5-15 mm. in thickness (figs. 13-14; 
pl. 12, a-h) ; the small variety ranges from 3-5 cm. in length, 2-3 cm. 
in width, and 5-8 mm. in thickness (fig. 15; pl. 12,¢-p). Although 
andesite is the most common rock material, fine-grained micaceous 
schist, quartz, limonite concretions, and gneiss are also used. 
Scrapers (fig. 16).—A series of quartz tools from several sites are 
classified as scrapers. The quartz of this area is poor quality and 
difficult to work by percussion chipping. However, by taking ad- 
vantage of the natural cleavage of the rock, it was possible to produce 
OF ts 62 SCM 
Ficure 14.—Large, percussion-made flake picks of the Alaka Phase. 
