﻿Appalachian 
  Geosyncline. 
  471 
  

  

  " 
  The 
  first 
  Paleozoic 
  land 
  flora 
  sufficiently 
  known 
  to 
  make 
  it 
  

   eligible 
  to 
  the 
  series 
  of 
  correlation 
  discussions 
  is 
  that 
  of 
  the 
  

   Middle 
  Devonian. 
  This 
  flora, 
  whose 
  apparent 
  meagerness 
  is 
  per- 
  

   haps 
  due 
  mostly 
  to 
  meagerness 
  of 
  information, 
  is 
  of 
  strange 
  and 
  

   forbidding 
  aspect 
  

  

  " 
  Evolution 
  of 
  forms 
  and 
  the 
  advent 
  of 
  new 
  types 
  mark 
  the 
  

   Upper 
  Devonian 
  flora, 
  which 
  bears 
  no 
  evidence 
  of 
  any 
  great 
  

   climatic 
  separation 
  from 
  the 
  preceding. 
  

  

  "The 
  Devonian 
  woods 
  present 
  no 
  annual 
  rings 
  to 
  bear 
  evidence 
  

   of 
  seasonal 
  changes 
  in 
  temperature 
  or 
  intervals 
  of 
  prolonged 
  

   drought. 
  . 
  . 
  . 
  

  

  " 
  The 
  step 
  from 
  the 
  Upper 
  Devonian 
  flora 
  to 
  that 
  of 
  the 
  

   Mississippian 
  ('Lower 
  Carboniferous') 
  is 
  marked 
  by 
  a 
  floral 
  

   contrast 
  which, 
  in 
  some 
  regions, 
  is 
  unexpectedly 
  sharp 
  through 
  

   the 
  warping 
  of 
  the 
  Devonian 
  floor 
  to 
  form 
  the 
  new 
  Carboniferous 
  

   synclines, 
  and 
  the 
  contraction 
  of 
  the 
  seas 
  naturally 
  premise 
  distinct 
  

   climatic 
  as 
  well 
  as 
  other 
  environmental 
  changes. 
  . 
  . 
  . 
  

  

  " 
  In 
  this 
  connection 
  it 
  may 
  be 
  noted 
  that, 
  either 
  on 
  account 
  of 
  

   land 
  or 
  marine 
  barriers, 
  or 
  because 
  the 
  climatic 
  conditions 
  through- 
  

   out 
  the 
  northern 
  hemisphere 
  may 
  at 
  the 
  outset 
  have 
  been 
  less 
  

   uniform 
  than 
  in 
  the 
  preceding 
  epoch, 
  the 
  different 
  areas 
  exhibit 
  

   more 
  or 
  less 
  distinct 
  local 
  floral 
  differences." 
  * 
  

  

  G. 
  W. 
  Matthew 
  states 
  

  

  " 
  The 
  conditions 
  of 
  climate 
  which 
  would 
  seem 
  to 
  have 
  best 
  

   suited 
  the 
  Devonian 
  types 
  was 
  that 
  of 
  a 
  dry 
  and 
  cool 
  atmosphere, 
  

   broken 
  annually 
  by 
  a 
  short 
  period 
  of 
  rains, 
  when 
  the 
  short 
  and 
  

   scanty 
  vegetation 
  made 
  a 
  rapid 
  growth. 
  Such 
  conditions 
  at 
  least 
  

   would 
  best 
  accord 
  with 
  the 
  prevalence 
  of 
  xerophytic 
  forms 
  like 
  

   the 
  Psilophyta 
  and 
  the 
  small 
  leaved 
  Lepidodendra, 
  and 
  the 
  rarity 
  

   of 
  the 
  Equisetinse. 
  Broad 
  leaved 
  plants 
  like 
  the 
  Cordaites 
  are 
  

   rare 
  in 
  the 
  Devonian 
  vegetation 
  and 
  the 
  filicoid 
  plants 
  are 
  mostly 
  

   of 
  the 
  genus 
  Archaeopteris. 
  The 
  plants 
  that 
  did 
  prevail 
  are 
  

   mostly 
  recorded 
  as 
  having 
  had 
  rhizomes 
  or 
  fleshy 
  root 
  stalks, 
  and 
  

   in 
  these 
  could 
  have 
  stored 
  up 
  the 
  nourishment 
  which 
  enabled 
  them 
  

   to 
  throw 
  out 
  a 
  vigorous 
  growth 
  at 
  that 
  time 
  of 
  the 
  year 
  when 
  the 
  

   season 
  of 
  expansion 
  arrived, 
  "f 
  

  

  The 
  flora 
  of 
  the 
  Little 
  River 
  Group, 
  concerning 
  which 
  Matthew 
  

   makes 
  these 
  remarks, 
  is 
  regarded 
  by 
  David 
  White 
  as 
  of 
  post- 
  

   Devonian 
  age. 
  This 
  may 
  be 
  accepted, 
  but 
  the 
  types 
  of 
  vegeta- 
  

   tion 
  are 
  such 
  as 
  mark 
  also 
  the 
  Upper 
  Devonian 
  and 
  the 
  same 
  

   inferences 
  as 
  to 
  climate 
  would 
  apply. 
  

  

  The 
  physical 
  and 
  organic 
  evidences 
  must 
  supplement 
  each 
  

   other 
  and 
  where 
  there 
  is 
  an 
  apparent 
  conflict 
  some 
  adjustment 
  

   of 
  views 
  must 
  be 
  made. 
  In 
  general 
  there 
  is 
  no 
  essential 
  

   discordance 
  of 
  the 
  two 
  lines 
  of 
  evidence, 
  but 
  the 
  presence 
  of 
  

  

  * 
  Jour. 
  Geol., 
  xvii, 
  pp. 
  322-324. 
  

  

  f 
  Review 
  of 
  the 
  Flora 
  of 
  the 
  Little 
  River 
  Group, 
  No. 
  Ill, 
  Trans. 
  Royal 
  

   Soc. 
  Can., 
  Third 
  Series 
  1910, 
  vol. 
  iv, 
  section 
  iv, 
  p. 
  8, 
  1911. 
  

  

  