﻿CANYON 
  FERRY 
  FOSSIL 
  VERTEBRATES 
  — 
  ^WHITE 
  429 
  

  

  present 
  distribution 
  of 
  mammals 
  in 
  North 
  America 
  had 
  been 
  in 
  

   operation 
  thi'oughout 
  the 
  Tertiary, 
  The 
  dimatic 
  zoning 
  of 
  mam- 
  

   mahan 
  distribution 
  in 
  North 
  America 
  by 
  C. 
  Hart 
  Merriam 
  (1892) 
  is 
  

   probably 
  familiar 
  to 
  nearly 
  everyone 
  and 
  will 
  not 
  be 
  further 
  discussed 
  

   here. 
  Many 
  workers 
  have 
  greatly 
  elaborated 
  and 
  refined 
  the 
  original 
  

   statement 
  (with 
  some 
  adverse 
  criticism), 
  but 
  the 
  basic 
  concept 
  is 
  

   still 
  valid. 
  

  

  It 
  is 
  the 
  purpose 
  of 
  the 
  present 
  study 
  to 
  compare 
  the 
  Lower 
  Oligo- 
  

   cene 
  faunas 
  of 
  the 
  plains 
  and 
  the 
  intermountain 
  basins 
  of 
  Montana 
  

   in 
  the 
  light 
  of 
  possible 
  climatic 
  zoning. 
  

  

  The 
  statement 
  often 
  has 
  been 
  made 
  that 
  the 
  nondiscovery 
  of 
  a 
  

   particular 
  form 
  in 
  a 
  given 
  deposit 
  is 
  not 
  proof 
  that 
  the 
  form 
  did 
  not 
  

   live 
  in 
  that 
  area 
  while 
  the 
  sediments 
  in 
  question 
  were 
  being 
  deposited. 
  

   In 
  general 
  this 
  is 
  true, 
  but 
  to 
  accept 
  it 
  as 
  an 
  axiom 
  is 
  to 
  exclude 
  from 
  

   consideration 
  aU 
  problems 
  of 
  distribution 
  and 
  intercontinental 
  migra- 
  

   tion 
  (see 
  Simpson, 
  1947, 
  p. 
  652). 
  Probably 
  the 
  greatest 
  value 
  of 
  the 
  

   statement 
  is 
  that 
  it 
  is 
  a 
  very 
  effective 
  intellectual 
  counterbalance 
  

   against 
  overenthusiastic 
  speculation. 
  For 
  application 
  to 
  a 
  specific 
  

   problem 
  it 
  must 
  be 
  weighted 
  against 
  the 
  answers 
  to 
  a 
  number 
  of 
  

   questions 
  : 
  

  

  1. 
  Was 
  the 
  area 
  accessible 
  to 
  the 
  animal 
  in 
  question? 
  

  

  2. 
  Is 
  it 
  known 
  from 
  older 
  or 
  younger 
  deposits 
  from 
  this 
  or 
  closely 
  adjacent 
  

  

  areas? 
  

  

  3. 
  Is 
  it 
  known 
  from 
  deposits 
  of 
  equivalent 
  age 
  from 
  adjacent 
  areas? 
  Or, 
  more 
  

  

  remote 
  areas? 
  

  

  4. 
  If 
  so, 
  how 
  frequently 
  is 
  it 
  encountered? 
  

  

  5. 
  Is 
  it 
  associated 
  with 
  other 
  genera 
  belonging 
  to 
  the 
  same 
  family? 
  

  

  6. 
  How 
  frequently 
  are 
  the 
  related 
  genera 
  encountered? 
  

  

  7. 
  Are 
  the 
  related 
  genera 
  found 
  in 
  the 
  deposit 
  in 
  question? 
  

  

  8. 
  Are 
  the 
  probable 
  habits 
  of 
  the 
  animal 
  in 
  question 
  such 
  that 
  its 
  remains 
  

  

  would 
  have 
  a 
  good 
  chance 
  of 
  being 
  buried 
  and 
  preserved? 
  

  

  9. 
  How 
  extensively 
  and 
  thoroughly 
  have 
  the 
  deposits 
  in 
  question 
  been 
  explored? 
  

  

  10. 
  Was 
  the 
  climate 
  and 
  environment 
  of 
  the 
  area 
  in 
  question 
  essentially 
  the 
  same 
  

  

  as 
  that 
  of 
  the 
  adjacent 
  area? 
  Of 
  the 
  more 
  remote 
  area? 
  

  

  11. 
  What 
  was 
  the 
  size 
  of 
  the 
  animal? 
  

  

  12. 
  What 
  was 
  the 
  probable 
  territorial 
  range 
  of 
  the 
  individual 
  estimated 
  from 
  the 
  

  

  size 
  and 
  inferred 
  habits? 
  

  

  If 
  the 
  faunas 
  of 
  Pipestone 
  Springs 
  and 
  Canyon 
  Ferry 
  (see 
  table 
  3) 
  

   are 
  compared 
  in 
  the 
  light 
  of 
  these 
  questions 
  it 
  will 
  be 
  seen 
  that, 
  since 
  

   the 
  two 
  areas 
  are 
  so 
  close 
  both 
  geographically 
  and 
  ecologically, 
  any 
  

   faunal 
  differences 
  must 
  be 
  attributed 
  to 
  the 
  accidents 
  of 
  preservation 
  

   and 
  discovery. 
  

  

  On 
  the 
  other 
  hand, 
  Pipestone 
  Springs 
  and 
  the 
  Badlands 
  of 
  South 
  

   Dakota 
  are 
  separated 
  by 
  a 
  distance 
  of 
  600 
  miles 
  (air 
  line), 
  3° 
  of 
  lati- 
  

   tude, 
  and 
  3,000 
  feet 
  of 
  altitude, 
  and 
  both 
  have 
  been 
  collected 
  exten- 
  

   sively. 
  Although 
  the 
  climate 
  of 
  Lower 
  Oligocene 
  times 
  may 
  have 
  

  

  