﻿98 
  0. 
  Holtedahl 
  — 
  Paleozoic 
  Formations 
  of 
  

  

  tated 
  material 
  irregularly 
  distributed 
  on 
  their 
  surface. 
  

   These 
  bodies 
  in 
  fact 
  seem 
  to 
  represent 
  a 
  structure 
  inter- 
  

   mediate 
  between 
  oolite 
  and 
  stromatolite. 
  

  

  Of 
  considerable 
  interest 
  is 
  the 
  fact 
  that 
  while 
  most 
  of 
  

   the 
  stromatolites 
  of 
  Finmarken 
  are 
  found 
  in 
  dolomite, 
  

   one 
  zone 
  (see 
  fig. 
  7) 
  occurs 
  in 
  a 
  rock 
  that 
  according 
  to 
  an 
  

   analysis 
  made 
  contains 
  87-6 
  per 
  cent 
  CaC0 
  3 
  and 
  only 
  

   0-57 
  per 
  cent 
  MgC0 
  3 
  , 
  thus 
  indicating 
  that 
  the 
  usual 
  high 
  

   content 
  of 
  magnesia 
  is 
  due 
  to 
  a 
  secondary 
  process, 
  a 
  dolo- 
  

   mitization 
  which 
  probably 
  took 
  place 
  very 
  soon 
  after 
  

   their 
  deposition. 
  

  

  Age 
  of 
  the 
  Porsanger 
  and 
  Var 
  anger 
  series. 
  — 
  As 
  to 
  the 
  

   age 
  of 
  this 
  older 
  dolomite-bearing 
  sandstone 
  division 
  of 
  

   Finmarken, 
  it 
  is 
  certainly 
  younger 
  than 
  the 
  Lower 
  Cam- 
  

   brian 
  shale 
  and 
  sandstone 
  with 
  Platys 
  olenites, 
  because 
  

   the 
  Porsanger 
  sandstone 
  is 
  found 
  to 
  lie 
  on 
  that 
  zone. 
  

   Further, 
  it 
  must 
  be 
  older 
  than 
  the 
  time 
  of 
  Caledonian 
  

   mountain-making, 
  as 
  the 
  dolomite-bearing 
  sandstones 
  are 
  

   overlaid 
  by 
  the 
  thrusted 
  mylonitic 
  rocks 
  of 
  the 
  Cale- 
  

   donian 
  deformation. 
  The 
  chief 
  period 
  of 
  the 
  Caledonian 
  

   deformation 
  in 
  this 
  part 
  of 
  the 
  world 
  probably 
  occurred 
  

   considerably 
  earlier 
  than 
  the 
  accepted 
  contact 
  zone 
  that 
  

   bounds 
  the 
  Silurian-Devonian, 
  for 
  in 
  the 
  island 
  of 
  Hit- 
  

   teren 
  of! 
  the 
  Norwegian 
  coast, 
  13 
  southwest 
  of 
  Trondhjem, 
  

   and 
  in 
  Spitzbergen, 
  14 
  Downtonian 
  unmetamorphosed 
  

   sandstones 
  occur 
  unconf 
  ormably 
  above 
  the 
  deeply 
  eroded 
  

   remnants 
  of 
  the 
  Caledonian 
  mountain 
  range. 
  

  

  It 
  is 
  now 
  known 
  that 
  in 
  the 
  Tromso 
  district 
  to 
  the 
  

   southwest 
  of 
  Finmarken 
  (and 
  likewise 
  in 
  the 
  Swedish 
  

   district 
  farther 
  south) 
  there 
  occurs 
  above 
  the 
  green 
  and 
  

   red 
  shales 
  of 
  the 
  Lower 
  Cambrian 
  (Hyolithus 
  zone) 
  and 
  

   below 
  the 
  mylonitic 
  rocks, 
  a 
  series 
  of 
  black 
  shales 
  of 
  con- 
  

   siderable 
  thickness. 
  As 
  suggested 
  especially 
  by 
  Th. 
  

   Vogt, 
  it 
  is 
  very 
  probable 
  that 
  this 
  series 
  corresponds 
  to 
  

   the 
  Middle, 
  possibly 
  also 
  to 
  the 
  Upper 
  Cambrian 
  black 
  

   shales 
  of 
  southern 
  Scandinavia. 
  This 
  series 
  of 
  black 
  

   shales 
  is 
  not 
  present 
  in 
  Finmarken, 
  as 
  here 
  the 
  Porsanger 
  

   sandstone 
  lies 
  directly 
  upon 
  the 
  Lower 
  Cambrian 
  green 
  

   and 
  red 
  shales 
  and 
  sandstones. 
  Therefore 
  a 
  break 
  seems 
  

   to 
  exist 
  here. 
  Now 
  if 
  we 
  consider 
  the 
  stratigraphical 
  

   sequences 
  in 
  the 
  different 
  Scandinavian-Baltic 
  Cambro- 
  

   Silurian 
  districts, 
  we 
  meet 
  a 
  striking 
  fact, 
  also 
  found 
  

  

  a 
  According 
  to 
  the 
  investigations 
  of 
  Reusch. 
  

   "According 
  to 
  the 
  investigations 
  of 
  Hoel 
  and 
  the 
  writer. 
  

  

  