﻿Geology 
  and 
  Natural 
  History. 
  75 
  

  

  the 
  Cenozoic 
  was 
  one 
  of 
  violent 
  crustal 
  movements, 
  ' 
  ' 
  and 
  of 
  con- 
  

   sequent 
  changes 
  in 
  climate 
  and 
  life." 
  Accordingly, 
  "in 
  the 
  

   area 
  described 
  in 
  this 
  paper 
  the 
  first 
  unconformity 
  above 
  rocks 
  

   of 
  undoubted 
  Cretaceous 
  age 
  marks 
  the 
  proper 
  Cretaceous-Ter- 
  

   tiary 
  boundary." 
  In 
  this 
  respect 
  he 
  "differs 
  from 
  some 
  geol- 
  

   ogists, 
  who 
  seem 
  to 
  place 
  emphasis 
  on 
  the 
  culmination 
  rather 
  than 
  

   on 
  the 
  inception 
  of 
  orogenic 
  movement." 
  It 
  is 
  true 
  that 
  in 
  the 
  

   area 
  studied 
  the 
  thin 
  Cretaceous 
  deposits 
  indicate 
  a 
  time 
  of 
  

   * 
  ' 
  quiescence, 
  ' 
  ' 
  but 
  in 
  western 
  Wyoming 
  and 
  Montana, 
  where 
  the 
  

   equivalent 
  formations 
  are 
  thick 
  with 
  the 
  thickness 
  and 
  coarse- 
  

   ness 
  of 
  the 
  rocks 
  increasing 
  upward 
  in 
  the 
  section 
  along 
  with 
  

   the 
  obliteration 
  of 
  the 
  Cretaceous 
  sea, 
  this 
  evidence 
  tends 
  to 
  show 
  

   that 
  earth 
  movement 
  had 
  already 
  begun 
  long 
  before 
  the 
  close 
  of 
  

   the 
  Cretaceous. 
  The 
  unconformity 
  represents 
  a 
  ' 
  ' 
  lost 
  interval 
  ' 
  ' 
  

   whose 
  duration 
  is 
  not 
  known, 
  but 
  some 
  portion 
  of 
  it 
  Lee 
  holds 
  

   must 
  be 
  of 
  Tertiary 
  time, 
  and 
  ' 
  ' 
  Tertiary 
  rocks 
  may 
  yet 
  be 
  found 
  

   that 
  are 
  older 
  than 
  those 
  of 
  the 
  Raton 
  formation. 
  " 
  " 
  The 
  uncon- 
  

   formity 
  seems 
  to 
  represent 
  all 
  of 
  Laramie 
  time 
  and 
  perhaps 
  some 
  

   of 
  late 
  Montana 
  time, 
  for 
  rocks 
  of 
  Montana 
  age 
  have 
  been 
  eroded 
  

   away. 
  ' 
  ' 
  The 
  differential 
  uplift 
  and 
  erosion 
  he 
  thinks 
  must 
  have 
  

   been 
  more 
  than 
  4,000 
  feet. 
  

  

  Then 
  Lee 
  goes 
  on 
  to 
  point 
  out 
  that 
  this 
  diastrophism 
  "resulted 
  

   in 
  the 
  withdrawal 
  of 
  the 
  Cretaceous 
  sea 
  and 
  the 
  upheaval 
  of 
  

   mountains 
  in 
  its 
  place. 
  ' 
  ' 
  Also 
  that 
  these 
  movements 
  ' 
  ' 
  naturally 
  

   caused 
  great 
  changes 
  in 
  climate, 
  and 
  therefore 
  in 
  plant 
  and 
  

   animal 
  life." 
  We 
  shall 
  see 
  later 
  on, 
  however, 
  that 
  there 
  was 
  

   no 
  appreciable 
  change 
  in 
  the 
  climate 
  nor 
  among 
  the 
  dinosaurs 
  

   at 
  the 
  time 
  of 
  this 
  earliest 
  earth 
  movement, 
  here 
  classified 
  as 
  of 
  

   Cenozoic 
  time, 
  and 
  yet 
  the 
  flora 
  of 
  the 
  Raton 
  was 
  decidedly 
  

   different 
  from 
  the 
  older 
  one, 
  in 
  fact, 
  so 
  much 
  so 
  that 
  Knowlton 
  

   easily 
  distinguishes 
  the 
  floras 
  of 
  the 
  Vermejo 
  from 
  those 
  of 
  the 
  

   Raton. 
  It 
  was 
  not 
  the 
  climate 
  (temperature 
  and 
  moisture) 
  that 
  

   brought 
  about 
  this 
  change, 
  as 
  the 
  floras 
  are 
  of 
  swamp 
  habitats 
  

   and 
  mild 
  temperatures, 
  nor 
  the 
  physiography, 
  for 
  the 
  dinosaurs 
  

   are 
  at 
  their 
  best 
  in 
  formations 
  here 
  classified 
  by 
  Lee 
  as 
  of 
  early 
  

   Eocene 
  time. 
  

  

  The 
  Vermejo 
  formation 
  of 
  late 
  Cretaceous 
  time, 
  and 
  in 
  the 
  

   main 
  of 
  fresh-water 
  origin, 
  has 
  a 
  flora 
  of 
  Montana 
  age. 
  It 
  is 
  

   a 
  distinct 
  and 
  older 
  flora 
  than 
  that 
  of 
  the 
  Laramie 
  of 
  the 
  Denver 
  

   basin. 
  On 
  the 
  other 
  hand, 
  the 
  invertebrates 
  found 
  in 
  the 
  Ver- 
  

   mejo 
  of 
  the 
  Canon 
  City 
  field 
  are 
  approximately 
  equivalent 
  in 
  age 
  

   to 
  those 
  of 
  the 
  Fox 
  Hills 
  of 
  the 
  Denver 
  basin. 
  

  

  The 
  Vermejo 
  and 
  the 
  Raton 
  are 
  superposed 
  formations 
  and 
  

   are 
  separated 
  by 
  the 
  unconformity 
  described 
  above. 
  The 
  Ver- 
  

   mejo 
  and 
  Trinidad 
  formations, 
  which 
  are 
  older 
  than 
  the 
  Laramie, 
  

   have 
  a 
  flora 
  of 
  108 
  species, 
  and 
  of 
  these 
  61 
  are 
  here 
  described 
  

   as 
  new. 
  To 
  attain 
  these 
  results, 
  Knowlton 
  had 
  to 
  revise 
  all 
  the 
  

   related 
  floras, 
  because 
  many 
  of 
  the 
  old 
  species 
  were 
  insufficiently 
  

   known 
  as 
  to 
  their 
  characters 
  and 
  geologic 
  position, 
  and 
  in 
  addi- 
  

  

  