c. Specimens of trapezoidal sliapc. This group 

 foi-ms the passage between the former and the 

 following one. 



f. Specimens of triangular shape These form a 



very interesting group, and at least ten sub- 

 groups could be distinguished These are : 



1. Right-handed specimens. 



2. Left'handed specimens- 



3. Isocoecle specimens with concave basis 



4. Isococclo specimens, with convex basis. 



5. Isocoecle specimens, with convex basis, ramer 



thin. 



6. Isocoecle specimens, both sides comcave. 



7. Rather flat, with strongly convex basis. 



8. Rather fiat, with left side concave. 

 9- Rather flat, with right side concave. 



10. Specimens with rather a convex Pollical face. 



g. Specimens of great thickness, in Wi^ich tae length 



exceeds breadth considerably. These speci- 

 mens practically form the passage to the 

 following group. On account of their thick- 

 ness they cannot be classified as knives, 

 though on account of their elongated fonti 

 they ought to be included among the follow- 

 ing group. 



F. KNIVES. 



Under these names I include all those implements in 

 which the length considerably exceeds the breadth. The 

 typical specimens are rather thin, and link themselves by 

 this feature to group D.e. (lamellifonn flakes of oval 

 shape). Other specimens are of a considerable thickness, 

 and in that case it is difficxilt to distinguish them from 

 group E.g. 



According to the number of longitudinal ridges on 

 the Indical face two large sub-groups can be distinguished, 

 riz : — 



I. One-ridged specimens- This type has only one- 

 longitudinal ridge more or less in the middle 

 of the Indical face. 



a. Specimens of considerable thickness, frequently 



pointed at one, sometimes at both ends. (See 

 E.g.) 



b. Flat specimens, pointed at one end. 



c. Long and narrow specimens, both edges welt 



trimmed- 



d. Short and broad specimens almost triangular. 



