﻿FOURTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I907 
  5 
  1 
  

  

  forming 
  circumscribed 
  areas 
  known 
  as 
  the 
  Cumberland 
  and 
  Indiana 
  

   basins. 
  The 
  western 
  interior 
  province 
  is 
  represented 
  typically 
  in 
  

   Iowa, 
  and 
  was 
  more 
  or 
  less 
  effectively 
  separated 
  from 
  the 
  eastern 
  

   during 
  early 
  and 
  Middle 
  Devonic 
  time. 
  Its 
  limits 
  are 
  coextensive 
  

   with 
  the 
  so 
  called 
  Dakota 
  sea, 
  which 
  was 
  open 
  to 
  the 
  northwest 
  

   during 
  the 
  mid-Devonic 
  through 
  Manitoba, 
  the 
  Mackenzie 
  Basin, 
  

   and 
  across 
  Behring 
  straits 
  into 
  Siberia, 
  but 
  was 
  probably 
  closed 
  to 
  

   the 
  northeast. 
  The 
  suggestion 
  has 
  been 
  made, 
  and 
  indeed 
  been 
  re- 
  

   ceived 
  with 
  some 
  favor, 
  that 
  intercommunication 
  existed 
  during 
  

   the 
  mid-Devonic 
  between 
  the 
  typical 
  Iowan 
  and 
  Eurasian 
  faunas 
  

   by 
  means 
  of 
  a 
  northeasterly 
  passageway 
  through 
  Manitoba, 
  Hudson 
  

   and 
  James 
  bays, 
  Greenland, 
  Spitzbergen 
  and 
  circumpolar 
  regions. 
  

   More 
  recently, 
  however, 
  weighty 
  objections 
  have 
  been 
  opposed 
  to 
  

   this 
  theory, 
  and 
  it 
  has 
  been 
  asserted 
  very 
  emphatically 
  by 
  Professor 
  

   Schuchert 
  that 
  there 
  is 
  not 
  the 
  slightest 
  reason 
  to 
  connect 
  the 
  Hudson 
  

   and 
  James 
  Bay 
  Devonic 
  with 
  that 
  of 
  the 
  Dakota 
  sea 
  (or 
  western 
  

   intercontinental 
  province). 
  It 
  is 
  further 
  denied 
  by 
  the 
  same 
  author 
  

   that 
  this 
  latter 
  province 
  was 
  in 
  connection 
  with 
  a 
  southern 
  ocean, 
  ex- 
  

   tending 
  into 
  Brazil, 
  until 
  Hamilton 
  time. 
  On 
  the 
  other 
  hand 
  

   students 
  are 
  agreed 
  that 
  communication 
  was 
  maintained 
  between 
  

   the 
  Appalachian 
  province 
  and 
  that 
  of 
  the 
  southern 
  hemisphere 
  

   during 
  the 
  mid-Devonic. 
  Concerning 
  the 
  pathways 
  that 
  were 
  open 
  

   between 
  the 
  Appalachian 
  and 
  Eurasian 
  provinces 
  during 
  the 
  Middle 
  

   and 
  later 
  Devonic 
  there 
  are 
  still 
  some 
  differences 
  of 
  opinion. 
  

  

  It 
  will 
  be 
  observed 
  accordingly, 
  that 
  the 
  Devonic 
  in 
  this 
  country 
  

   was 
  preeminently 
  an 
  era 
  of 
  provincial 
  development 
  of 
  marine 
  

   faunas. 
  Furthermore 
  it 
  appears 
  that 
  diversity 
  in 
  this 
  respect 
  is 
  

   more 
  strongly 
  marked 
  in 
  the 
  Appalachian 
  region, 
  where 
  there 
  were 
  

   varying 
  conditions 
  of 
  sedimentary 
  deposition, 
  than 
  in 
  the 
  Cordilleran 
  

   and 
  continental 
  border 
  regions, 
  where 
  these 
  conditions 
  were 
  more 
  

   uniform. 
  Thus, 
  in 
  the 
  eastern 
  province, 
  as 
  Professor 
  Williams 
  has 
  

   pointed 
  out, 
  diversity 
  and 
  alternation 
  of 
  deposits 
  are 
  accompanied 
  

   by 
  numerous 
  successive 
  and 
  distinct 
  faunas 
  ; 
  in 
  the 
  extreme 
  western 
  

   regions, 
  uniformity 
  of 
  prevailing 
  calcareous 
  sedimentation 
  for 
  long 
  

   periods 
  is 
  characterized 
  by 
  the 
  abnormally 
  long 
  continuance 
  of 
  many 
  

   Devonic 
  species 
  ; 
  and 
  the 
  central 
  continental 
  province, 
  midway 
  

   between 
  the 
  two, 
  is 
  marked 
  by 
  the 
  unmistakable 
  recurrence 
  of 
  

   Devonic 
  species 
  well 
  along 
  into 
  the 
  Carbonic. 
  Another 
  noteworthy 
  

   feature 
  of 
  the 
  Devonic 
  which 
  has 
  been 
  developed 
  very 
  fully 
  and 
  

   clearly 
  by 
  the 
  painstaking 
  investigation 
  of 
  Dr 
  Clarke 
  is 
  that 
  faunal 
  

   changes 
  within 
  the 
  ancient 
  Appalachian 
  sea 
  are 
  sometimes 
  so 
  pre- 
  

   cisely 
  indicated 
  that 
  it 
  is 
  possible, 
  as 
  in 
  the 
  case 
  of 
  the 
  Portage 
  

   group, 
  to 
  trace 
  the 
  boundaries 
  not 
  only 
  of 
  local 
  provinces, 
  but 
  of 
  

   local 
  subprovinces 
  characterizing 
  the 
  stage 
  in 
  question. 
  Thus, 
  the 
  

   Genesee 
  province 
  of 
  the 
  Portage 
  is 
  divided 
  into 
  Chautauquan 
  and 
  

   Naples 
  subprovinces 
  on 
  the 
  basis 
  of 
  differences 
  in 
  their 
  faunal 
  

   facies 
  ; 
  and 
  an 
  interesting 
  peculiarity 
  of 
  the 
  Naples 
  subprovince 
  is 
  

   that, 
  as 
  stated 
  by 
  Dr 
  Clarke 
  ""with 
  contemporaneous 
  faunas 
  of 
  the 
  

   Appalachian 
  gulf 
  " 
  its 
  fauna 
  " 
  has 
  in 
  its 
  purity 
  no 
  organic 
  relation, 
  

   direct 
  or 
  sequential." 
  

  

  