60 THK MANlJKACTl'Ur. oK THK TKKO-WATTA, 



11. In the internal flakes one or more previous planes 

 of fracture form the Indical face. 



12. External and inLernal flakes of the first order have 

 no special percussion face; the latter is formed by the 

 original surface of the parent block. 



13. External and internal flakes of the second order 

 have a special percussion face (a former plane of fracture) 

 which, though sometimes greatly reduced by marginal 

 trimming, foi-ms an angle, of about 135deg. with the Pol- 

 lical face. 



14- The production of a flat, smooth Pollical face waa 

 the essential feature in striking ofi" a flake from the parent 

 block. This condition could only be fulfllled if the ham- 

 mer struck the parent block at an angle of about 45deg. 



15. The future shape of the tero-watta was primarily 

 determined by the shapo of the orginal flake. 



16. A flake detached from a parent block may have 

 been used without further trimming or not. If it was 

 the Indical face only was worked, but never the Pollical 

 face. (N.B. — There are certain exceptions of this rule, 

 mostly in such instances when in the case of an internal 

 flake there was little difference between Indical and Pol- 

 lical face.) 



17. Invariably the trimming of the Indical face or 

 the edges was done by blows fx-om the Pollical towards the 

 Indical face, and never vice versa. (N.B. — There are cer- 

 tain exceptions, but they do not materially afifect this 

 rule.) 



18. The trimming of the Indical face or the edges was 

 in all probability done by means of a spherical hammer. 

 In marginal trimn.ing the blows were not set close, but at 

 regular intervals, the saw-like edge thus resulting was sub- 

 sequently straightened by striking of tlie "teeth-" 



19. In round figures 75 per cent, of the finished tero- 

 watta weighed under 8 ounces, while only 25 pc cent, 

 weighed more than 8 ounces- The largest number, 32 per 

 cent., weighed between 2 and 4 ounces, while only 14 per 

 cent., a good number of which arc perhaps unfinished re- 

 jects, weighed more than lib. 



