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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  by 
  the 
  beavers. 
  They 
  plowed 
  their 
  channel 
  right 
  through 
  the 
  cen- 
  

   ter 
  of 
  the 
  swale 
  and 
  hanked 
  both 
  sides 
  of 
  the 
  canal 
  (pi. 
  2, 
  fig. 
  1). 
  

   In 
  1916, 
  when 
  the 
  work 
  was 
  new, 
  the 
  levees 
  so 
  constructed 
  were 
  

   very 
  conspicuous, 
  and 
  sufficiently 
  high 
  to 
  enable 
  the 
  beavers 
  to 
  fill 
  

   the 
  canal 
  to 
  a 
  level 
  appreciably 
  higher 
  than 
  that 
  of 
  much 
  of 
  the 
  

   immediately 
  adjacent 
  terrain. 
  In 
  winter 
  these 
  levees 
  gave 
  rise 
  to 
  

   an 
  especially 
  curious 
  effect 
  at 
  times, 
  for 
  when 
  the 
  snow 
  receded 
  

   they 
  were 
  exposed 
  first 
  and 
  showed 
  as 
  two 
  narrow 
  parallel 
  ridges 
  

   protruding 
  through 
  the 
  white 
  mantle 
  covering 
  the 
  canal 
  and 
  the 
  

   surface 
  of 
  the 
  swale 
  (pi. 
  2, 
  fig. 
  2). 
  Beginning 
  exactly 
  at 
  the 
  

   lower 
  end 
  of 
  the 
  flooded 
  slough, 
  though 
  a 
  little 
  to 
  the 
  north- 
  

   east 
  of 
  the 
  center 
  thereof, 
  the 
  levees 
  featured 
  the 
  canal 
  for 
  a 
  dis- 
  

   tance 
  of 
  some 
  215 
  feet. 
  In 
  fact, 
  this 
  entire 
  lower 
  portion 
  of 
  the 
  

   canal 
  was 
  very 
  regular 
  and 
  as 
  exact 
  in 
  construction 
  as 
  rather 
  care- 
  

   ful 
  human 
  hands 
  would 
  likely 
  have 
  made 
  it. 
  An 
  entertaining 
  

   incident 
  occurred 
  in 
  1916, 
  the 
  year 
  the 
  works 
  first 
  came 
  under 
  ob- 
  

   servation, 
  when 
  one 
  of 
  the 
  ranch 
  hands 
  chanced 
  to 
  place 
  a 
  large 
  board 
  

   across 
  the 
  canal 
  to 
  serve 
  as 
  a 
  bridge 
  in 
  passing 
  over 
  it. 
  The 
  beavers 
  

   failed 
  to 
  appreciate 
  this 
  obstruction 
  to 
  their 
  traffic 
  and 
  at 
  once 
  got 
  

   about 
  its 
  removal. 
  Whether 
  one, 
  or 
  more 
  than 
  one, 
  animal 
  was 
  so 
  

   engaged 
  we 
  did 
  not 
  discover, 
  but 
  in 
  any 
  case 
  the 
  board 
  was 
  set 
  upon 
  

   from 
  both 
  sides 
  without 
  much 
  evident 
  coordination 
  of 
  effort. 
  Two 
  

   good-sized 
  crescents 
  were 
  thus 
  bitten 
  away, 
  but 
  not 
  being 
  coincidently 
  

   directed 
  the 
  obard 
  was 
  still 
  holding 
  pretty 
  well 
  when 
  I 
  last 
  saw 
  it 
  

   (pi. 
  6, 
  fig. 
  1). 
  This 
  is 
  hardly 
  to 
  be 
  adduced 
  as 
  proof 
  of 
  very 
  keen 
  

   intelligence 
  on 
  the 
  part 
  of 
  the 
  beaver, 
  but 
  it 
  must 
  be 
  admitted 
  that 
  

   man 
  himself 
  would 
  obtain 
  a 
  poor 
  verdict 
  were 
  he 
  similarly 
  judged 
  

   on 
  some 
  of 
  his 
  own 
  incidental 
  behavior. 
  

  

  Although 
  I 
  speak 
  of 
  the 
  canal 
  as 
  opening 
  into 
  the 
  river, 
  I 
  never 
  

   was 
  able 
  to 
  determine 
  which 
  end 
  was 
  actually 
  the 
  head 
  and 
  which 
  

   the 
  foot 
  of 
  the 
  main 
  portion. 
  When 
  I 
  first 
  saw 
  it 
  in 
  July, 
  1916, 
  

   all 
  the 
  water 
  was 
  out 
  of 
  it 
  except 
  a 
  mere 
  trickle 
  which 
  drained 
  

   into 
  the 
  river. 
  There 
  were 
  plenty 
  of 
  fresh 
  beaver 
  tracks 
  in 
  the 
  

   muddy 
  bottom 
  and 
  those 
  of 
  white-tail 
  deer, 
  coyotes, 
  wild 
  cats, 
  

   and 
  a 
  few 
  smaller 
  animals 
  along 
  the 
  levees. 
  In 
  1918 
  it 
  was 
  full, 
  

   or 
  nearly 
  full, 
  of 
  water, 
  which 
  was 
  slowly 
  flowing 
  away 
  from 
  the 
  

   river 
  and 
  into 
  the 
  slough. 
  That 
  same 
  summer 
  a 
  little 
  later 
  I 
  

   saw 
  the 
  water 
  in 
  the 
  canal 
  so 
  nearly 
  neutral 
  between 
  river 
  and 
  

   slough 
  that 
  floating 
  particles 
  moved 
  now 
  one 
  way, 
  now 
  the 
  other, 
  in 
  

   the 
  most 
  indeterminate 
  fashion. 
  Sometimes 
  the 
  water 
  was 
  noted 
  to 
  

   be 
  flowing 
  steadily 
  toward 
  the 
  river. 
  The 
  obvious 
  explanation 
  of 
  

   this 
  curious 
  state 
  of 
  affairs 
  would 
  seem 
  to 
  be 
  that 
  this 
  part 
  of 
  the 
  

   canal 
  was 
  so 
  nearly 
  level 
  that 
  the 
  direction 
  of 
  whatever 
  current 
  mani- 
  

   fested 
  itself 
  depended 
  wholly 
  upon 
  the 
  relative 
  levels 
  of 
  the 
  water 
  

  

  