CELTS. 23 



a high degree of development in the art of chipping. True flint and obsidian, 

 for example, seem to have been practically unknown. 



The technique included chipping, pecking, grinding and polishing. The col- 

 lection of celts comprises specimens in various stages of development, from which 

 the processes of working and the resultant shapes may be determined. These 

 seem to vary in a measure with the character of the material. For example, a 

 certain type of celt is usually made of a black fine-grained volcanic tufa, ranging 

 in hardness from that of hornfels on the one hand to basanite or touchstone on 

 the other. The implements of this group are always chipped and not pecked. 

 On the other hand those made of silicified volcanic ash and of andesitic lava take 

 other forms and are usually pecked and not chipped. 



The chipped types of celt are shown in Plate II (figs, a and h). The compara- 

 tively slender and graceful shape in figure a is due entirely to chipping, the only 

 polished areas being the facets that meet to form the edge. The materials of this 

 group are the black fine-grained volcanic tufas resembling hornfels and basanite. 

 The surface of the specimens is covered uniformly with a whitish patina. In 

 figure h the polishing reaches almost the entire length of the blade and the two 

 polished faces form each a single convex surface. Celts similar in shape to these 

 were found by Hartman in the highland plains of Costa Rica, Province of Cartago. 



Sometimes the shape is varied by the production of three facets, the bevels 

 that produce the edge, however, never reaching more than about half-way to the 

 base (fig. c). A specimen resembling this was described by Simonin 1 as being 

 found in the grave of an ancient Chiriquian goldsmith. 



Early stages in the pecked type of implement are reproduced in figures d and e. 

 The larger looks as if it had been made from an oblong, flattened, water-worn 

 pebble, tapering toward one end. The latter becomes the base or pole (called 

 by Sir John Evans, " butt-end "). The polishing extends backward along a median 

 line to the very tip of the pole, a feature which distinguishes the pecked type 

 from the polished type. The lateral facets are left unpolished. In the smaller 

 specimen the polished bevels at the edge extend but a short distance toward the 

 pole, a single exception proving the rule. 



Figure / is a typical example. The lines are all gracefully wrought out, those 

 bounding the polished facets converging artistically and extending from the corners 

 of the cutting edge to the very tip of the pole. The lateral facets are coarsely 

 ground. These also are sometimes polished as in figure g, which represents a 

 high degree of artistic skill and finish. 



Two variants from the general type are given in figures b and i. In the former 

 there is a marked constriction in the blade immediately above the corners of the 

 edge. In the latter the edge is comparatively straight and long. The length, 

 however, has been somewhat reduced by polishing off the corners. 



Figure 6 represents a class with rounded, even cylindrical, section and thick 

 blunt pole. Specimens of this group seem to have been shaped by pecking, 

 grinding and polishing. In some examples the entire surface is polished. The 

 material is generally a compact volcanic tufa, reddish to black in color. 



1 Op. cit, fig. 139. 



