﻿28 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  4 
  That 
  in 
  the 
  later 
  stage 
  represented 
  by 
  the 
  profuse 
  fauna 
  of 
  

   the 
  Grande 
  Greve 
  Hmestones 
  the 
  northern 
  passage 
  broadened 
  while 
  

   the 
  Dalhousie 
  passage 
  became 
  extinct; 
  and 
  that 
  passage 
  remained 
  

   open 
  till 
  much 
  later 
  in 
  the 
  Devonic 
  than 
  Ilelderbergian 
  time. 
  

   This 
  fact 
  is 
  evinced 
  by 
  the 
  somewhat 
  lessened 
  though 
  by 
  no 
  means 
  

   obliterated 
  presence 
  of 
  Helderberg 
  species, 
  by 
  the 
  full 
  develop- 
  

   ment 
  of 
  characteristic 
  Oriskany 
  species 
  in 
  the 
  purest 
  limestone 
  

   medium 
  and 
  the 
  existence 
  of 
  certain 
  types 
  of 
  still 
  later 
  (Onon- 
  

   daga) 
  age 
  in 
  minor 
  phases 
  of 
  development. 
  The 
  opinion 
  has 
  been 
  

   expressed 
  that 
  during 
  this 
  period 
  of 
  the 
  Grande 
  Greve 
  limestones 
  

   the 
  Gaspe 
  Basin 
  was 
  a 
  place 
  of 
  rapid 
  fructification 
  and 
  departure 
  

   of 
  the 
  fauna 
  toward 
  the 
  southwest. 
  

  

  5 
  In 
  northern 
  Maine 
  that 
  part 
  of 
  the 
  Devonic 
  represented 
  by 
  the 
  

   arenaceous, 
  sediments 
  of 
  Aroostook 
  county 
  must 
  have 
  pertained 
  

   to 
  a 
  distinct 
  geographic 
  passageway 
  and 
  have 
  been 
  more 
  or 
  less 
  

   obstructed 
  southward 
  during 
  the 
  period 
  of 
  the 
  Oriskany. 
  It 
  is 
  

   quite 
  possible 
  that 
  the 
  same 
  channel 
  was 
  open 
  in 
  its 
  southwest 
  

   extent 
  during 
  Helderbergian 
  time 
  as 
  indicated 
  by 
  the 
  fauna 
  of 
  

   the 
  Square 
  Lake 
  limestone, 
  though 
  the 
  differences 
  therein 
  from 
  

   the 
  New 
  York 
  Helderbergian 
  would 
  still 
  indicate 
  that 
  the 
  way 
  was 
  

   then 
  not 
  entirely 
  clear 
  open 
  and 
  carried 
  basins 
  of 
  special 
  develop- 
  

   ment. 
  

  

  6 
  The 
  development 
  of 
  the 
  early 
  Devonic 
  fauna 
  in 
  Piscataquis 
  

   and 
  Somerset 
  counties, 
  Me., 
  though 
  this 
  series 
  of 
  rocks 
  is 
  ap- 
  

   parently 
  not 
  widely 
  separated 
  in 
  continuity 
  or 
  direction 
  from 
  the 
  

   Aroostook 
  county 
  faunas, 
  is 
  unlike 
  the 
  latter, 
  is 
  more 
  decided 
  in 
  

   its 
  representation 
  of 
  New 
  York 
  Oriskany 
  types, 
  and 
  yet 
  has 
  many 
  

   special 
  features 
  in 
  common 
  with 
  those 
  of 
  Aroostook 
  county. 
  At 
  

   all 
  events 
  this 
  area 
  indicates 
  no 
  entire 
  severance 
  from 
  the 
  former 
  

   and 
  also 
  declares 
  for 
  a 
  wide 
  open 
  passage 
  southward. 
  

  

  7 
  As 
  far 
  southward 
  as 
  northern 
  Maine 
  the 
  calcareous 
  character 
  

   of 
  the 
  Oriskany 
  facies*is 
  already 
  lost 
  in 
  spite 
  of 
  its 
  predominance 
  

   further 
  north 
  and 
  east, 
  yet 
  in 
  this 
  regard 
  it 
  can 
  not 
  be 
  said 
  to 
  

   conform 
  more 
  fully 
  with 
  the 
  New 
  York 
  development 
  for 
  that, 
  in 
  

   spite 
  of 
  common 
  repute, 
  has 
  been 
  abundantly 
  shown 
  to 
  be 
  more 
  

   calcareous 
  than 
  arenaceous, 
  save 
  as 
  the 
  limestones 
  of 
  the 
  New 
  

   York 
  Oriskany 
  carry 
  large 
  percentages 
  of 
  silica 
  and 
  weather 
  

   freely 
  to 
  a 
  silicious 
  residuum. 
  

  

  8 
  The 
  more 
  southerly 
  of 
  these 
  passages 
  show 
  in 
  their 
  fauna 
  

   traits 
  which 
  the 
  northerly 
  do 
  not, 
  namely, 
  a 
  striking 
  array 
  of 
  

   affiliations 
  with 
  the 
  Coblentzian 
  fauna 
  of 
  the 
  Transatlantic. 
  It 
  

   would 
  be 
  difficult 
  to 
  assign 
  any 
  other 
  reason 
  for 
  this 
  than 
  that 
  

  

  