﻿10:2 
  0. 
  Holtedahl 
  — 
  Paleozoic 
  Formations 
  of 
  

  

  the 
  corresponding 
  different 
  f 
  acies 
  of 
  the 
  British 
  Isles 
  and 
  

   of 
  eastern 
  North 
  America. 
  

  

  There 
  is 
  reason 
  to 
  believe 
  that 
  the 
  npper 
  part 
  of 
  the 
  

   very 
  thick 
  dolomite-bearing 
  division 
  of 
  Finmarken 
  

  

  Fig. 
  8. 
  

  

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  7 
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  )7\ 
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  / 
  

  

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  v\ 
  

  

  

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  r"~~ 
  

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  / 
  

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  Fig. 
  8. 
  — 
  Paleogcography 
  of 
  early 
  Ordovician 
  time. 
  Black 
  squares 
  indicate 
  

   occurrences 
  of 
  dolomite 
  and 
  limestone 
  of 
  Ozarkian-Canadian 
  age, 
  and 
  of 
  

   American-Arctic 
  facies. 
  Vertical 
  lines, 
  areas 
  of 
  probable 
  further 
  extension. 
  

   Horizontal 
  lines, 
  .areas 
  of 
  Atlantic-European 
  facies 
  with 
  Dictyogrcptus. 
  

   Between 
  the 
  broken 
  lines 
  occur 
  the 
  assumed 
  land-masses. 
  

  

  reaches 
  as 
  high 
  into 
  the 
  Ordovician 
  as 
  the 
  Tetragraptus 
  

   (Phyllograptus) 
  horizon 
  correlated 
  with 
  the 
  British 
  

   Arenig. 
  It 
  is 
  also 
  of 
  considerable 
  interest 
  to 
  point 
  out 
  

   that 
  this 
  time 
  in 
  Scotland 
  was 
  one 
  of 
  extreme 
  volcanic 
  

   activity, 
  which 
  may 
  correspond 
  with 
  the 
  Raipas 
  erup- 
  

   tions. 
  Recently 
  Carstens 
  has 
  shown 
  that 
  eruptions 
  took 
  

  

  