﻿IS 
  THE 
  EARTH 
  GROWING 
  OLD? 
  POMPECKJ 
  265 
  

  

  gions. 
  The 
  differing 
  composition 
  of 
  rocks 
  formed 
  contempora- 
  

   neously 
  in 
  different 
  regions 
  shows 
  this 
  as 
  well 
  as 
  the 
  varying 
  amounts 
  

   of 
  the 
  existing 
  rocks 
  formed 
  in 
  the 
  same 
  time 
  at 
  different 
  places. 
  

   In 
  the 
  same 
  region 
  the 
  formation 
  of 
  rocks 
  varies 
  in 
  time 
  sequence; 
  

   that 
  is, 
  the 
  factors 
  leading 
  to 
  the 
  accumulation 
  of 
  rocks 
  have 
  varied 
  

   in 
  intensity 
  and 
  action 
  in 
  the 
  course 
  of 
  time. 
  In 
  the 
  sequence 
  of 
  the 
  

   rocks 
  of 
  the 
  earth's 
  crust 
  we 
  find 
  almost 
  endlessly 
  occurring 
  cyclic 
  

   or 
  rhythmic 
  variations. 
  Some 
  of 
  them 
  are 
  directly 
  the 
  consequences 
  

   of 
  movements 
  in 
  the 
  scaffolding 
  of 
  the 
  earth 
  as 
  shown 
  in 
  the 
  rock 
  

   series 
  conditioned 
  by 
  the 
  transgression 
  and 
  regression 
  of 
  the 
  seas. 
  

   Others 
  document 
  the 
  influences 
  of 
  the 
  rhythmical 
  climatic 
  variations 
  

   which 
  are 
  in 
  their 
  turn 
  bound 
  up 
  with 
  the 
  motions 
  of 
  the 
  earth's 
  crust. 
  

   W. 
  Ramsay 
  was 
  able 
  to 
  show 
  this 
  convincingly 
  in 
  his 
  fine 
  study, 
  

   " 
  Orogenesis 
  and 
  climate." 
  

  

  Rhythms 
  are 
  the 
  most 
  evident, 
  the 
  most 
  striking 
  features 
  found 
  in 
  

   the 
  developments 
  of 
  the 
  earth's 
  history. 
  

  

  The 
  great 
  massive 
  upheavals 
  of 
  the 
  earth's 
  crust 
  like 
  that 
  of 
  the 
  

   Scandinavian 
  Peninsula, 
  the 
  subsidings 
  like 
  that 
  of 
  the 
  bottom 
  of 
  

   France, 
  occur 
  rhythmically. 
  They 
  allow 
  the 
  sea 
  to 
  flood 
  the 
  land 
  

   and 
  then 
  to 
  recede. 
  The 
  repeated 
  alternations 
  of 
  sea 
  and 
  land 
  are 
  

   rhj^thmical. 
  The 
  formation 
  of 
  mountain 
  chains 
  hj 
  the 
  foldings 
  of 
  

   the 
  earth's 
  crust 
  is 
  rhythmical. 
  Volcanic 
  activity 
  occurs 
  rhythmi- 
  

   cally. 
  The 
  great 
  ice 
  ages 
  of 
  the 
  earth 
  occurred 
  rhythmically 
  and 
  

   were 
  differentiated 
  rhythmically 
  among 
  themselves. 
  

  

  Rhythm 
  dominates 
  the 
  onward 
  flow 
  of 
  the 
  earth's 
  history; 
  never 
  

   was 
  there 
  uniformity 
  in 
  its 
  paces. 
  

  

  Do 
  these 
  geological 
  rhythms 
  reoccur 
  at 
  equal* 
  lapses 
  of 
  time, 
  or 
  

   are 
  the 
  intervals 
  becoming 
  longer 
  between 
  rhythms 
  of 
  the 
  same 
  class 
  ? 
  

   Are 
  the 
  expressions 
  of 
  the 
  separate 
  acmes 
  becoming 
  weaker 
  ? 
  Is 
  there 
  

   any 
  increasing 
  insensitiveness 
  of 
  the 
  earth 
  to 
  the 
  actuating 
  forces 
  

   offering 
  an 
  evidence 
  of 
  old 
  age? 
  

  

  Let 
  us 
  consider 
  the 
  formation 
  of 
  mountain 
  chains 
  through 
  folding. 
  

  

  In 
  the 
  oldest 
  period 
  of 
  the 
  earth's 
  history 
  known 
  to 
  us 
  there 
  is 
  such 
  

   a 
  widespread 
  folding 
  of 
  the 
  earth's 
  crust 
  known 
  that 
  it 
  is 
  indeed 
  

   ubiquitous. 
  It 
  amounts 
  to 
  a 
  general 
  wrinkling 
  of 
  the 
  earth's 
  surface. 
  

   Although 
  it 
  is 
  impossible 
  with 
  any 
  success 
  to 
  apply 
  the 
  methods 
  of 
  

   geology 
  to 
  determining 
  the 
  times 
  of 
  relative 
  occurrence 
  of 
  the 
  rocks 
  

   of 
  the 
  Archaic 
  times 
  in 
  regions 
  separated 
  from 
  each 
  other, 
  we 
  can 
  at 
  

   least 
  conclude 
  from 
  the 
  discordances 
  between 
  the 
  Archaic 
  rock 
  series 
  

   that 
  the 
  formation 
  of 
  the 
  foldings 
  of 
  that 
  era 
  did 
  not 
  owe 
  their 
  

   existence 
  either 
  to 
  a 
  temporary 
  process 
  or 
  one 
  general 
  throughout 
  

   that 
  period. 
  For 
  the 
  subsequent 
  foldings 
  of 
  the 
  Algonkian 
  era, 
  

   although 
  even 
  here 
  the 
  comparisons 
  are 
  yet 
  uncertain, 
  we 
  can 
  say 
  

  

  