﻿GEOLOGICAL 
  CLIMATES 
  

  

  By 
  W. 
  B. 
  Scott 
  

  

  HISTORICAL 
  STATEMENT 
  

  

  Very 
  early 
  in 
  the 
  history 
  of 
  our 
  science 
  it 
  became 
  evident 
  that 
  the 
  

   earth 
  had 
  passed 
  through 
  great 
  climatic 
  changes, 
  and 
  the 
  effort 
  to 
  

   find 
  an 
  explanation 
  of 
  these 
  changes 
  which 
  should 
  be 
  adequate 
  and 
  

   satisfactory 
  has 
  never 
  ceased 
  till 
  this 
  day. 
  There 
  has 
  of 
  late 
  been 
  a 
  

   revival 
  of 
  interest 
  in 
  this 
  problem, 
  and 
  many 
  new 
  works 
  on 
  the 
  

   subject 
  have 
  appeared 
  in 
  this 
  country, 
  as 
  well 
  as 
  in 
  England 
  and 
  

   Germany. 
  

  

  One 
  great 
  obstacle 
  in 
  the 
  way 
  of 
  finding 
  convincing 
  explanations 
  

   for 
  past 
  climatic 
  changes 
  was 
  the 
  fact 
  that 
  since 
  weather 
  records 
  have 
  

   been 
  kept 
  no 
  definite 
  changes 
  of 
  climate 
  could 
  be 
  detected, 
  though 
  

   it 
  was 
  admitted 
  that 
  those 
  records 
  covered 
  too 
  short 
  a 
  period 
  of 
  

   observation 
  to 
  be 
  at 
  all 
  decisive. 
  Some 
  historians, 
  notably 
  Gibbon, 
  

   in 
  his 
  famous 
  Decline 
  and 
  Fall 
  of 
  the 
  Roman 
  Empire, 
  have 
  attempted 
  

   to 
  prove 
  the 
  reality 
  of 
  climatic 
  changes 
  within 
  the 
  historic 
  period, 
  

   especially 
  in 
  central 
  Europe, 
  but 
  the 
  evidence 
  is 
  not 
  satisfactory. 
  The 
  

   appeal 
  to 
  agencies 
  still 
  in 
  operation, 
  the 
  study 
  of 
  which 
  constitutes 
  

   dynamical 
  geology, 
  would 
  seem, 
  therefore, 
  to 
  be 
  impracticable. 
  

  

  The 
  uniform 
  distribution 
  of 
  the 
  vegetation 
  of 
  the 
  " 
  Coal 
  Measures 
  " 
  

   over 
  immense 
  areas, 
  involving 
  very 
  great 
  differences 
  of 
  latitude, 
  is 
  

   of 
  itself 
  a 
  problem 
  that 
  has 
  not 
  been 
  satisfactorily 
  solved 
  even 
  yet. 
  

   One 
  of 
  the 
  most 
  eloquent 
  of 
  Hugh 
  Miller's 
  descriptive 
  passages 
  is 
  

   his 
  imaginative 
  reconstruction 
  of 
  the 
  climate 
  and 
  weather 
  conditions 
  

   which 
  obtained 
  in 
  the 
  great 
  bogs 
  and 
  marshes 
  of 
  Carboniferous 
  time. 
  

   As 
  coal 
  is 
  composed 
  chiefly 
  of 
  carbon, 
  which 
  had 
  been 
  derived 
  from 
  

   the 
  atmosphere 
  through 
  the 
  agency 
  of 
  living 
  plants, 
  it 
  was 
  taken 
  for 
  

   granted 
  at 
  that 
  time 
  that 
  all 
  of 
  it 
  had 
  existed 
  in 
  the 
  atmosphere 
  simul- 
  

   taneously 
  in 
  the 
  form 
  of 
  carbon 
  dioxide; 
  but 
  this 
  would 
  have 
  had 
  

   very 
  remarkable 
  consequences, 
  many 
  of 
  which 
  were 
  not 
  known 
  in 
  

   Miller's 
  day. 
  Miller 
  does 
  not 
  seem 
  to 
  ascribe 
  the 
  climatic 
  conditions 
  

   to 
  the 
  atmospheric 
  composition, 
  since 
  he 
  gives 
  no 
  discussion 
  of 
  the 
  

   causes 
  of 
  climatic 
  change, 
  but 
  the 
  juxtaposition 
  of 
  the 
  supposed 
  facts 
  

   is 
  suggestive. 
  

  

  1 
  Presidential 
  address 
  read 
  liefore 
  the 
  Geological 
  Society 
  of 
  A]u<-rica, 
  Dee. 
  28, 
  1925. 
  

   Reprinted 
  by 
  permission 
  from 
  the 
  Bulletin 
  of 
  the 
  Geological 
  Society 
  of 
  America, 
  vol. 
  37, 
  

   Mar. 
  30, 
  1926. 
  

  

  271 
  

  

  