﻿regarding 
  the 
  Periodic 
  Submergence 
  of 
  Europe. 
  39 
  

  

  During 
  the 
  deposition 
  of 
  the 
  Coral 
  Pag 
  the 
  waters 
  remained 
  

   shallow. 
  The 
  crust 
  subsided 
  at 
  the 
  beginning 
  of 
  Kimmeridge 
  

   time, 
  and 
  another 
  upward 
  movement 
  began 
  at 
  the 
  end 
  of 
  the 
  

   deposition 
  of 
  the 
  Portland 
  limestone 
  (79-81). 
  

  

  Heberfs 
  conclusions. 
  — 
  We 
  have 
  "shown 
  that 
  the 
  crustal 
  

   movements 
  were 
  not 
  at 
  all 
  peculiar 
  to 
  the 
  Paris 
  basin, 
  but 
  that 
  

   they 
  also 
  affected 
  the 
  ancient 
  rocks 
  which 
  form 
  the 
  circumfer- 
  

   ence 
  of 
  the 
  Paris 
  depression. 
  These 
  movements 
  are 
  so 
  

   coordinated 
  that 
  we 
  can 
  consider 
  them 
  as 
  being 
  part 
  of 
  a 
  single 
  

   great 
  oscillation 
  composed 
  of 
  two 
  periods, 
  one 
  during 
  which 
  

   the 
  crust 
  was 
  slowly 
  and 
  progressively 
  depressed, 
  the 
  other 
  

   during 
  which 
  it 
  was 
  raised. 
  

  

  Each 
  of 
  these 
  periods 
  was 
  itself 
  divided 
  by 
  secondary 
  oscil- 
  

   lations, 
  because 
  of 
  which 
  the 
  land 
  was 
  successively 
  lowered 
  or 
  

   raised, 
  but 
  in 
  such 
  a 
  way 
  that, 
  during 
  the 
  first 
  period, 
  the 
  sea, 
  

   in 
  each 
  one 
  of 
  these 
  secondary 
  oscillations, 
  finally 
  gained 
  some 
  

   land, 
  while, 
  on 
  the 
  contrary, 
  it 
  lost 
  some 
  during 
  the 
  second 
  

   period. 
  

  

  These 
  movements 
  of 
  the 
  crust 
  had 
  more 
  or 
  less 
  influence 
  on 
  

   the 
  distribution 
  of 
  the 
  lands 
  and 
  waters, 
  and 
  consequently 
  on 
  

   the 
  climates, 
  and 
  from 
  this 
  came 
  the 
  changes 
  in 
  the 
  organic 
  

   realm. 
  These 
  changes 
  can 
  be 
  appreciated 
  to-day 
  only 
  through 
  

   the 
  remains 
  of 
  marine 
  animals 
  which 
  accompany 
  the 
  sediments 
  

   of 
  each 
  epoch. 
  They 
  alone, 
  however, 
  are 
  numerous 
  enough 
  to 
  

   form 
  a 
  sufficient 
  assemblage 
  of 
  facts. 
  

  

  When, 
  as 
  a 
  result 
  of 
  this 
  movement, 
  the 
  change 
  in 
  physical 
  

   conditions 
  was 
  considerable, 
  the 
  organic 
  modifications 
  were 
  

   profound. 
  Moreover, 
  it 
  seems 
  evident 
  that 
  the 
  maximitm 
  

   change 
  must 
  correspond 
  to 
  the 
  maximum 
  elevation 
  of 
  the 
  earth 
  

   and 
  the 
  minimum 
  to 
  the 
  maximum 
  depression. 
  The 
  maxi- 
  

   mum 
  elevation, 
  when 
  the 
  lands 
  are 
  most 
  emergent, 
  corre- 
  

   sponds 
  to 
  the 
  moment 
  when 
  the 
  sea 
  is 
  farthest 
  awa}^ 
  from 
  the 
  

   point 
  under 
  consideration, 
  where 
  there 
  is 
  consequently 
  the 
  

   longest 
  absence 
  of 
  sedimentation 
  ; 
  the 
  two 
  beds 
  nearest 
  to 
  this 
  

   limit 
  are, 
  then, 
  those 
  which 
  will 
  differ 
  the 
  most. 
  

  

  Let 
  us 
  apply 
  this 
  fact 
  to 
  the 
  present 
  case. 
  In 
  the 
  Jurassic 
  

   epoch 
  there 
  were 
  two 
  maxima 
  of 
  elevation, 
  one 
  at 
  the 
  begin- 
  

   ning, 
  the 
  other 
  at 
  the 
  end. 
  To 
  understand 
  these 
  better, 
  we 
  

   must 
  investigate 
  the 
  movements 
  which 
  took 
  place 
  during 
  the 
  

   Triassic 
  and 
  Cretaceous 
  epochs. 
  

  

  During 
  the 
  Triassic 
  epoch, 
  at 
  the 
  time 
  of 
  the 
  deposition 
  of 
  

   the 
  variegated 
  sandstones, 
  the 
  eastern 
  part 
  of 
  the 
  Paris 
  basin 
  

   was 
  a 
  shore 
  ; 
  the 
  sea 
  occupied 
  it 
  at 
  the 
  time 
  of 
  the 
  Muschelkalk, 
  

   and 
  left 
  it 
  at 
  the 
  time 
  of 
  the 
  variegated 
  marls. 
  The 
  Triassic 
  

   was, 
  then, 
  deposited 
  during 
  an 
  oscillation 
  of 
  the 
  crust, 
  which 
  

   had 
  been 
  depressed 
  up 
  to 
  the 
  time 
  of 
  the 
  Muschelkalk, 
  to 
  rise 
  

   again 
  at 
  the 
  time 
  of 
  the 
  deposition 
  of 
  the 
  variegated 
  marls. 
  

  

  