﻿Diastrophism 
  in 
  Atlantic- 
  Arctic 
  Region. 
  25 
  

  

  not 
  at 
  the 
  time 
  of 
  the 
  Caledonian 
  deformation 
  situated 
  at 
  

   the 
  border 
  of 
  a 
  deep 
  ocean, 
  but 
  at 
  that 
  of 
  a 
  land-mass, 
  

   and 
  the 
  folded 
  zone 
  thus 
  did 
  not 
  have 
  the 
  characters 
  of 
  a 
  

   shelf. 
  

  

  If, 
  however, 
  in 
  the 
  light 
  of 
  the 
  previous 
  discussion, 
  we 
  

   consider 
  this 
  land 
  area, 
  like 
  that 
  of 
  Appalachia, 
  as 
  an 
  

   especially 
  unstable 
  one, 
  we 
  might, 
  through 
  vertical 
  move- 
  

   ments 
  here, 
  get 
  conditions 
  favoring 
  a 
  magmatic 
  under- 
  

   flow 
  in 
  the 
  bordering 
  (geosynclinal) 
  zone, 
  this 
  underflow 
  

   causing 
  folding 
  of 
  the 
  crust. 
  This 
  bordering 
  zone 
  

   between 
  the 
  unstable 
  area 
  and 
  the 
  stable 
  continental 
  one 
  

   would 
  naturally 
  be 
  one 
  of 
  large 
  sedimentation, 
  the 
  latter 
  

   being 
  especially 
  great 
  when 
  the 
  unstable 
  area 
  was 
  highly 
  

   elevated. 
  Through 
  isostatic 
  adjustment, 
  this 
  accumula- 
  

   tion 
  of 
  sediments 
  might 
  cause 
  a 
  continual 
  sinking 
  of 
  the 
  

   crust, 
  and 
  we 
  would 
  thus 
  have 
  here 
  the 
  characteristic 
  

   features 
  of 
  a 
  geosyncline. 
  The 
  primary 
  process 
  of 
  crust 
  

   movement 
  in 
  the 
  geosynclinal 
  belts 
  would, 
  according 
  to 
  

   the 
  above 
  view, 
  be 
  the 
  vertical 
  movements 
  of 
  the 
  unstable, 
  

   now 
  oceanic 
  areas, 
  which 
  movements 
  then 
  in 
  turn 
  have 
  to 
  

   be 
  explained. 
  

  

  I 
  shall 
  not 
  go 
  further 
  into 
  these 
  theoretical 
  specula- 
  

   tions, 
  which 
  are 
  a 
  natural 
  consequence 
  of 
  the 
  present 
  

   paleogeographic 
  study. 
  I 
  hope 
  it 
  will 
  be 
  understood 
  

   that 
  the 
  northern 
  region 
  especially 
  considered 
  in 
  this 
  

   article, 
  though 
  having 
  no 
  youthful 
  mountain 
  ranges 
  and 
  

   though 
  hiding 
  much 
  of 
  its 
  ancient 
  geography 
  behind 
  the 
  

   impenetrable 
  veil 
  of 
  highly 
  metamorphic 
  rocks 
  and 
  under 
  

   the 
  cover 
  of 
  the 
  sea, 
  may 
  yet, 
  through 
  constant 
  and 
  de- 
  

   tailed 
  work, 
  contribute 
  in 
  considerable 
  degree 
  to 
  the 
  

   knowledge 
  of 
  paleogeography 
  and 
  the 
  nature 
  of 
  dias- 
  

   trophism. 
  

  

  Kristiania, 
  Norway, 
  May, 
  1919. 
  

  

  