﻿in 
  North 
  America. 
  205 
  

  

  Dr. 
  J. 
  E. 
  Clark 
  and 
  Mr. 
  Schuchert* 
  have 
  attempted 
  to 
  

   prove, 
  on 
  paleontological 
  grounds, 
  that 
  the 
  Lower 
  Helderberg 
  

   fauna 
  has 
  a 
  Devonian 
  " 
  aspect," 
  and, 
  trusting 
  to 
  their 
  theories, 
  

   have 
  proposed 
  to 
  classify 
  the 
  formations 
  containing 
  the 
  typical 
  

   Lower 
  Helderberg 
  faunas 
  in 
  the 
  Devonian 
  system. 
  f 
  

  

  When 
  Professor 
  Ivayser's 
  paper 
  first 
  appeared 
  I 
  was 
  struck 
  

   with 
  the 
  force 
  of 
  his 
  paleontological 
  argument 
  for 
  classifying 
  

   the 
  Lower 
  Helderberg 
  and 
  Hercynian 
  faunas 
  together 
  ; 
  but 
  I 
  

   was 
  not 
  then 
  satisfied 
  with 
  the 
  proof 
  of 
  the 
  Devonian 
  age 
  of 
  

   all 
  the 
  faunas 
  so 
  classified. 
  When 
  Dr. 
  Barrois 
  1 
  paper, 
  on 
  the 
  

   Erbray 
  faunas 
  appeared^ 
  it 
  was 
  gratifying 
  to 
  find 
  confirma- 
  

   tion 
  of 
  this 
  opinion. 
  

  

  Dr. 
  Freck's 
  papers§ 
  were 
  also 
  emphatic 
  in 
  claiming 
  a 
  

   Devonian 
  age 
  for 
  the 
  Hercynian, 
  and 
  the 
  combined 
  evidence 
  

   of 
  these 
  gentlemen 
  (and 
  others 
  taking 
  part 
  in 
  the 
  discussion), 
  

   pointed 
  very 
  strongly 
  to 
  the 
  conclusion 
  that 
  we 
  must 
  drop 
  our 
  

   Silurian-Devonian 
  boundary 
  below 
  the 
  main 
  part 
  of 
  the 
  Lower 
  

   Helderberg, 
  if 
  we 
  would 
  adopt 
  European 
  (continental) 
  usage. 
  

  

  The 
  similarity 
  of 
  the 
  Gaspe 
  section 
  to 
  the 
  typical 
  Welsh 
  

   sections 
  of 
  the 
  Silurian 
  system, 
  running 
  up 
  to 
  the 
  base 
  of 
  the 
  

   Old 
  Bed 
  sandstone, 
  gave 
  me 
  hopes 
  that 
  a 
  study 
  of 
  the 
  sections 
  

   in 
  northern 
  Maine 
  might 
  reveal 
  some 
  faunas 
  representing 
  the 
  

   upper 
  part 
  of 
  the 
  Silurian 
  more 
  closely 
  than 
  do 
  the 
  faunas 
  of 
  

   Xew 
  York. 
  As 
  the 
  fossils 
  of 
  Maine, 
  were 
  studied, 
  a 
  transi- 
  

   tion 
  fauna 
  was 
  found 
  which 
  throws 
  considerable 
  light 
  upon 
  the 
  

   exact 
  position 
  of 
  the 
  boundary 
  plane 
  between 
  the 
  two 
  systems, 
  

   Silurian 
  and 
  Devonian, 
  in 
  our 
  North 
  American 
  rocks. 
  

  

  The 
  fauna 
  referred 
  to 
  was 
  first 
  discovered 
  by 
  Olof 
  O. 
  Ny- 
  

   lander, 
  in 
  the 
  town 
  of 
  Chapman, 
  Aroostook 
  County, 
  Maine, 
  in 
  

   a 
  sandstone, 
  called 
  Chapman 
  sandstone, 
  in 
  a 
  report 
  on 
  the 
  geol- 
  

   ogy 
  of 
  Maine 
  recently 
  made 
  to 
  the 
  U. 
  S. 
  Geological 
  Survey 
  

   [which 
  will 
  appear 
  as 
  Bulletin 
  Xo. 
  165]. 
  The 
  fauna 
  is 
  being 
  

   described 
  and 
  figured, 
  but 
  a 
  preliminary 
  examination 
  of 
  it 
  has 
  

   revealed 
  its 
  close 
  correlation 
  with 
  the 
  Ludlow 
  Tilestone 
  fauna 
  

   of 
  Murchison, 
  and 
  still 
  more 
  closely 
  with 
  the 
  Upper 
  Arisaig 
  

   fauna, 
  D 
  of 
  Honeyman's 
  section, 
  which 
  was 
  " 
  unhesitatingly 
  

   referred 
  to 
  the 
  Ludlow 
  Tilestone" 
  by 
  Salter, 
  in 
  1862. 
  || 
  

  

  This 
  Chapman 
  sandstone 
  fauna 
  is 
  the 
  latest 
  marine 
  paleozoic 
  

   fauna 
  so 
  far 
  recognized 
  in 
  Maine, 
  unless 
  the 
  Moose 
  River 
  

   fauna 
  with 
  Oriskany 
  species 
  be 
  a 
  little 
  later. 
  It 
  is 
  contained 
  

  

  -The 
  nomenclature 
  of 
  the 
  Xew 
  York 
  series 
  of 
  Geological 
  formations, 
  Science, 
  

   X. 
  S 
  . 
  vol. 
  x. 
  pp. 
  874-878. 
  Dec. 
  15, 
  1899. 
  

  

  -r 
  See 
  pap°r 
  read 
  at 
  the 
  Geol. 
  Soc 
  America. 
  Washington, 
  December, 
  1899. 
  

  

  \ 
  Fauna 
  du 
  Calcaire 
  D'Krbray, 
  by 
  Charles 
  Barrois. 
  Mem. 
  de 
  la 
  Soc. 
  geologique 
  

   du 
  Xord. 
  tome 
  iii. 
  April, 
  1889. 
  

  

  § 
  Ueber 
  das 
  rheinische 
  Unterdevon 
  und 
  die 
  Stellung 
  des 
  " 
  Hercyn/' 
  by 
  Fritz 
  

   Freck: 
  Zeitschr. 
  d. 
  Deutsch. 
  geolog. 
  Gesellschaft; 
  Jahrg. 
  1889, 
  pp. 
  175-287, 
  etc. 
  

   art. 
  Jour. 
  Geol. 
  Soc. 
  xx. 
  p. 
  334. 
  1864. 
  

  

  