148  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
blades  were  used  only  on  the  smaller  harpoon  heads.  They  are  bev- 
eled only  at  the  tip  or  just  along  the  edges  ;  none  has  the  median  ridge 
or  broad  faceted  edges  such  as  are  found  on  the  Thule  harpoon  blades ; 
they  are  also  longer  and  somewhat  narrower  at  the  base  than  the  Thule 
types.  At  about  the  center  they  are  usually  no  more  than  i  mm  in 
thickness,  at  the  tip  about  2  mm. 
Harpoon  or  knife  blades. — Under  this  heading  comes  a  much  larger 
number  of  blades  of  rubbed  slate,  chipped  slate,  and  chipped  chert 
or  jasper. 
(7.  Rubbed  slate. — Those  of  rubbed  slate  are  tanged,  symmetrical 
in  outline,  and  usually  have  a  median  ridge  extending  from  tip  to 
about  center ;  below  the  ridge  and  to  each  side  of  it  the  blade  is  bev- 
eled, producing  a  three-faceted  surface  (pi.  39,  figs.  6-12).  The 
average  length  is  5  to  6  cm  and  breadth  3  to  3.5  cm.  The  greatest 
thickness  is  at  the  lower  or  proximal  end  of  the  median  ridge,  where 
it  averages  4  to  6  mm.  Undoubtedly,  some  of  these  were  used  as  har- 
poon blades.  Many  of  the  Old  Bering  Sea  harpoon  heads  have  blade 
slits  3  mm  wide  and  up  to  4  cm  long,  which  would  require  a  blade 
of  just  this  length  and  thickness  but  which  would  be  too  large  for 
the  very  thin  blades  of  the  type  shown  in  plate  39,  figures  1-5.  On  the 
other  hand,  it  is  also  certain  that  some  of  these  larger  tanged  speci- 
mens were  used  as  knife  blades  (e.  g.  pi.  38,  fig.  i),  and  since  there 
seems  to  be  no  way  of  distinguishing  between  the  two,  they  are  here 
grouped  together. 
Plate  39,  figure  13,  is  the  lower  end  of  a  large  slate  blade  for  either 
a  knife  or  a  lance.  Blades  of  this  size  and  shape  were  rare  at  the 
Hillside  site. 
b.  Chipped  slate. — The  76  blades  of  chipped  slate  from  the  Hillside 
site  are  difficult  to  classify  because  of  uncertainty  as  to  which  are 
finished  and  which  unfinished  specimens.  In  plate  40,  figures  i-io,  are 
shown  some  of  the  tanged  forms,  most  of  which  were  no  doubt  used 
as  knife  blades,  although  plate  40,  figure  8,  might  possibly  be  an 
unfinished  blade  of  the  type  shown  in  plate  39,  figures  6-12.  The  two 
slate  blades,  plate  40,  figures  20-21,  are  unfinished  forms  or  rejects,  and 
there  are  numerous  others  similar  in  shape  but  smaller,  which  may 
have  been  arrow  points  or  unfinished  harpoon  blades  of  the  thin,  small, 
tangless  type. 
c.  Chipped  chert  or  jasper. — There  are  20  of  these,  the  types  of 
which  are  shown  in  plate  40,  figures  11-19.  The  smaller  blades,  such 
as  figures  12-14,  were  probably  used  as  arrow  points,  and  figures  15 
and  16  may  have  been  side  blades  for  harpoon  heads.  The  larger  ones, 
figures  II,  17-19,  were  no  doubt  knife  blades. 
