98  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
They  are  found  in  all  sorts  of  places  and  under  all  manner  of  conditions.  Very 
often  they  come  from  widely  separated  sites.  They  are  collected  in  enormous 
quantities  and  in  most  bewildering  variety.  And,  being  undocumented,  they  are 
at  first  contact  entirely  undatable.  To  bring  these  into  sequence,  there  must  be 
selected  certain  classes  of  specimens  which,  more  clearly  and  more  easily  than 
others,  can  be  used  as  indicators  of  the  passage  of  time,  and  which  can  serve 
as  preliminary  criteria  for  determining  the  relative  age  of  the  less  readily 
seriated  remains  with  which  they  are  associated.  Any  class  of  objects  to  be 
employed  in  this  way  must  possess  certain  indispensable  characteristics.  The 
specimens  which  go  to  make  it  up  must  be  imperishable,  they  must  be  abundant' 
and  widely  disseminated,  and  they  must  be  of  such  a  nature  as  very  sensitively 
to  register  cultural  change.    [Kidder,   1931,  pp.  3-4.] 
Harpoon  heads  fulfill  the  above  requirements  admirably.  They  are 
abundant  (the  Gambell  excavations  yielded  417  specimens  that  could 
be  identified  as  to  type,  in  addition  to  many  fragments)  ;  they  are 
widely  distributed,  in  a  number  of  different  forms,  from  northeastern 
Asia  to  Greenland ;  they  are  of  durable  material — ivory  or  bone — 
which  is  usually  well  preserved  in  the  frozen  soil ;  and  most  im- 
portant of  all,  they  are  complicated  in  form,  and  in  Alaska,  often 
elaborately  ornamented.  The  relative  abundance  of  harpoon  heads 
in  the  middens  is  explained  by  the  fact  that  this  is  the  detachable  part 
of  the  harpoon,  the  part  that  strikes  and  enters  the  prey,  and  which 
being  subject  to  considerable  stress  and  strain,  is  often  broken,  and 
later  discarded.  The  harpoon  head  is  complex  in  structure,  possessing 
at  least  six  features  that  often  exhibit  a  wide  range  of  variability  :  ( i ) 
the  shaft  socket  at  the  lower  or  proximal  end  for  engaging  the  end 
of  the  foreshaft;  (2)  the  lashing  slots  or  other  means  whereby  (in 
those  with  open  sockets)  the  foreshaft  is  held  in  the  socket;  (3) 
the  pointed  lower  end,  or  spur ;  (4)  the  central  perforation,  or  line 
hole,  by  means  of  which  the  harpoon  head  is  attached  to  the  line ; 
(5)  the  presence  or  absence  of  lateral  barbs  or  inset  stone  blades ;  (6) 
the  anterior  end  which  may  or  may  not  be  slit  for  the  purpose  of 
holding  an  end  blade.  In  addition  there  are  certain  combinations  of 
these  features  to  be  noted,  and  other  characters  such  as  size,  pro- 
portion of  parts,  and  technique,  all  of  which  may  and  often  do  have 
a  diagnostic  value.  A  further  fortunate  circumstance  is  that  during 
the  Old  Bering  Sea  and  Punuk  periods  harpoon  heads  were  decorated 
more  frequently  than  any  other  class  of  artifacts,  and  in  such  a  way 
that  there  was  often  a  very  definite  correlation  between  the  form  of 
the  harpoon  head  and  the  ornamentation  it  received. 
For  convenience  of  reference  it  will  be  necessary  to  arrange  our 
harpoon  heads  according  to  some  definite  order.  We  have  the  choice 
of  two  methods :  first,  to  establish  an  exact,  comprehensive  classifica- 
