﻿Dakota 
  Strata 
  of 
  Kansas. 
  295 
  

  

  nian 
  of 
  the 
  Upper 
  or 
  Neo-Cretaceous 
  of 
  Europe, 
  20 
  of 
  

   which 
  the 
  Dakota 
  has 
  long 
  been 
  considered 
  the 
  equiva- 
  

   lent. 
  21 
  The 
  general 
  drift 
  of 
  American 
  opinion, 
  so 
  far 
  as 
  

   the 
  writer 
  has 
  been 
  able 
  to 
  learn 
  it, 
  also 
  appears 
  to 
  have 
  

   been 
  toward 
  correlation 
  of 
  the 
  "Washita, 
  at 
  least 
  the 
  upper 
  

   part, 
  with 
  the 
  Cenomanian. 
  22 
  In 
  Europe 
  the 
  time 
  of 
  the 
  

   Cenomanian 
  witnessed 
  a 
  great 
  transgression 
  which 
  ex- 
  

   tended 
  beyond 
  the 
  limits 
  of 
  the 
  Lower 
  Cretaceous 
  sea, 
  

   so 
  that 
  the 
  strata 
  of 
  this 
  European 
  division 
  now 
  hold 
  

   the 
  same 
  position 
  with 
  respect 
  to 
  invasion 
  that 
  is 
  held 
  

   by 
  the 
  Benton 
  of 
  the 
  Plains. 
  23 
  

  

  This 
  raises 
  the 
  question 
  as 
  to 
  what 
  should 
  constitute 
  

   the 
  boundary 
  of 
  a 
  larger 
  time 
  unit. 
  On 
  the 
  basis 
  of 
  

   diastrophism, 
  the 
  plane 
  of 
  separation 
  between 
  the 
  Upper 
  

   and 
  Lower 
  Cretaceous 
  in 
  Kansas 
  and 
  adjacent 
  states 
  

   should 
  be 
  placed 
  at 
  the 
  top 
  of 
  the 
  "Washita 
  and 
  its 
  equiva- 
  

   lents. 
  In 
  Europe 
  it 
  apparently 
  should 
  be 
  placed 
  at 
  the 
  

   base 
  of 
  the 
  Cenomanian 
  — 
  considered 
  by 
  many 
  European 
  

   students 
  the 
  equivalent 
  of 
  the 
  Washita. 
  Thus 
  the 
  dias- 
  

   trophic 
  principle 
  places 
  the 
  break 
  on 
  one 
  continent 
  at 
  

   one 
  level 
  and 
  on 
  another 
  continent 
  at 
  a 
  different 
  level. 
  

   There 
  ought 
  to 
  be 
  nothing 
  strange 
  about 
  this 
  — 
  it 
  seems 
  

   that 
  such 
  should 
  be 
  normal 
  rather 
  than 
  otherwise 
  — 
  and 
  

   the 
  writer 
  is 
  inclined 
  to 
  the 
  opinion 
  that 
  it 
  will 
  ultimately 
  

   be 
  found 
  to 
  be 
  true 
  for 
  several 
  of 
  the 
  larger 
  time 
  units, 
  

   especially 
  when 
  we 
  get 
  away 
  from 
  the 
  present 
  concep- 
  

   tion 
  that 
  the 
  order 
  of 
  historic 
  events 
  on 
  this 
  continent 
  

   was 
  the 
  same 
  as 
  in 
  the 
  Old 
  World. 
  He 
  would 
  go 
  still 
  

   further 
  and 
  insist 
  that 
  such 
  is 
  quite 
  likely 
  to 
  be 
  the 
  case 
  

   for 
  some 
  of 
  the 
  larger 
  time 
  units 
  even 
  on 
  opposite 
  sides 
  

   of 
  the 
  same 
  continent, 
  thus 
  agreeing 
  with. 
  Willis 
  that 
  

   "Each 
  region 
  has 
  experienced 
  an 
  individual 
  history 
  of 
  

   diastrophism, 
  in 
  which 
  the 
  law 
  of 
  periodicity 
  is 
  expressed 
  

   in 
  cycles 
  of 
  movement 
  peculiar 
  to 
  the 
  region 
  " 
  and 
  "The 
  

   periods 
  of 
  diastrophic 
  activity' 
  ' 
  have 
  been 
  "as 
  regards 
  

   the 
  whole 
  surface 
  of 
  the 
  earth 
  in 
  general 
  not 
  contempo- 
  

   raneous. 
  " 
  24 
  

  

  20 
  A. 
  de 
  Lapparent, 
  Traite 
  de 
  Geologie, 
  vol. 
  3, 
  p. 
  1408, 
  1906. 
  

  

  E. 
  Haug, 
  Traite 
  de 
  Geologie, 
  pt. 
  2, 
  p. 
  1293, 
  1907. 
  

   21 
  E. 
  Kayser, 
  Lehrbuch 
  der 
  Geologie, 
  pt. 
  2, 
  p. 
  513, 
  1908. 
  

  

  22 
  C. 
  Schuchert, 
  Bull. 
  Geol. 
  Soc. 
  Am., 
  20, 
  584-585, 
  1910. 
  Stanton 
  also 
  

   quoted 
  to 
  that 
  effect. 
  

  

  23 
  De 
  Lapparent, 
  op. 
  cit. 
  p. 
  1384. 
  

  

  J. 
  Parks, 
  A 
  Text-Book 
  of 
  Geology, 
  p. 
  412, 
  London, 
  1914. 
  

  

  T. 
  C. 
  Chamberlin 
  and 
  B. 
  D. 
  Salisbury, 
  Geology, 
  vol. 
  3, 
  p. 
  168, 
  1907. 
  

  

  24 
  Bailey 
  Willis, 
  Science, 
  new 
  ser., 
  31, 
  247, 
  249, 
  1910. 
  

  

  