﻿GEOLOGICAL 
  CLIMATES 
  SCOTT 
  283 
  

  

  Many 
  observations 
  have 
  been 
  made 
  which 
  strongly 
  suggest 
  that 
  

   the 
  relation 
  between 
  loading 
  of 
  the 
  land 
  with 
  ice 
  and 
  subsequent 
  

   de]:)ression 
  is 
  more 
  than 
  coincidence. 
  But 
  if 
  that 
  were 
  all, 
  why 
  did 
  

   the 
  process 
  cease? 
  Why 
  was 
  the 
  last 
  melting 
  of 
  the 
  ice 
  not 
  fol- 
  

   lowed 
  by 
  a 
  renewed 
  elevation 
  of 
  the 
  land 
  ? 
  It 
  may 
  be 
  said 
  that 
  not 
  

   time 
  enough 
  has 
  elapsed 
  since 
  the 
  last 
  disappearance 
  of 
  the 
  ice, 
  

   and 
  that 
  we 
  are 
  slowly 
  but 
  surely 
  advancing 
  to 
  a 
  new 
  glacial 
  epoch. 
  

   Perhaps 
  so, 
  but 
  there 
  is 
  no 
  sufficient 
  evidence 
  of 
  a 
  universal 
  rise 
  of 
  

   the 
  land 
  in 
  high 
  latitudes, 
  such 
  as 
  would 
  be 
  called 
  for 
  on 
  this 
  

   hypothesis. 
  Furthermore, 
  if 
  diastrophic 
  movements 
  were 
  the 
  sole 
  

   cause 
  of 
  the 
  glacial 
  and 
  interglacial 
  alternation, 
  we 
  should 
  have 
  no 
  

   explanation 
  of 
  the 
  fact 
  that 
  in 
  some, 
  at 
  least, 
  of 
  the 
  interglacial 
  

   stages 
  the 
  climate 
  was 
  warmer 
  than 
  at 
  the 
  present 
  time. 
  Some 
  ad- 
  

   ditional 
  factor 
  is 
  called 
  for. 
  

  

  I 
  can 
  not 
  but 
  agree 
  with 
  Jeffreys 
  in 
  his 
  conclusion 
  that, 
  while 
  dias- 
  

   trophic 
  movements 
  of 
  the 
  earth's 
  crust 
  are 
  a 
  very 
  real 
  cause 
  of 
  cli- 
  

   matic 
  change, 
  they 
  are 
  insufficient 
  to 
  account 
  for 
  the 
  accepted 
  history 
  

   of 
  the 
  vicissitudes 
  of 
  climate 
  through 
  which 
  the 
  earth 
  has 
  passed. 
  

   The 
  lowered 
  temperature 
  of 
  the 
  Pleistocene 
  was 
  a 
  world-wide 
  phe- 
  

   nomenon 
  and 
  is 
  registered 
  in 
  all 
  the 
  great 
  land 
  masses 
  of 
  both 
  

   Northern 
  and 
  Southern 
  Hemispheres. 
  Even 
  in 
  the 
  Tropics 
  the 
  ice 
  

   limit 
  was 
  several 
  thousand 
  feet 
  below 
  that 
  of 
  the 
  present 
  day. 
  We 
  

   have 
  no 
  satisfactory 
  proof 
  of 
  a 
  correspondingly 
  universal 
  upwarp- 
  

   ing 
  of 
  the 
  lands, 
  and 
  therefore 
  the 
  diastrophic 
  hypothesis, 
  as 
  it 
  may 
  

   be 
  called, 
  is 
  inadequate 
  as 
  the 
  sole 
  explanation 
  of 
  the 
  facts. 
  

  

  It 
  should 
  be 
  added 
  that 
  a 
  great 
  deal 
  remains 
  to 
  be 
  learned 
  con- 
  

   cerning 
  the 
  Pleistocene 
  glaciation 
  of 
  the 
  Southern 
  Hemisphere, 
  for 
  

   little 
  intensive 
  study 
  has 
  as 
  yet 
  been 
  devoted 
  to 
  the 
  problems 
  in- 
  

   volved. 
  It 
  is 
  not 
  definitely 
  known, 
  for 
  example, 
  whether 
  glacial 
  

   and 
  interglacial 
  alternations 
  characterized 
  the 
  continents 
  of 
  the 
  

   Southern 
  as 
  they 
  did 
  those 
  of 
  tlie 
  Northern 
  Hemisphere, 
  nor 
  how 
  

   many 
  glacial 
  stages 
  there 
  were, 
  or 
  if, 
  indeed, 
  there 
  was 
  more 
  than 
  

   one. 
  Obviously, 
  a 
  complete 
  theory 
  of 
  the 
  Pleistocene 
  climates 
  can 
  

   not 
  be 
  formulated 
  until 
  much 
  more 
  has 
  been 
  learned 
  regarding 
  the 
  

   southern 
  continents 
  in 
  that 
  epoch. 
  

  

  II. 
  So 
  far 
  we 
  have 
  dealt 
  entirely 
  with 
  supposed 
  agencies 
  of 
  cli- 
  

   matic 
  change 
  which 
  have 
  affected 
  the 
  earth 
  only, 
  either 
  as 
  a 
  whole 
  

   or 
  in 
  part. 
  In 
  the 
  second 
  principal 
  category 
  of 
  hypotheses 
  the 
  

   causes 
  of 
  climatic 
  change 
  are 
  sought 
  for 
  in 
  agencies 
  entirely 
  outside 
  

   of 
  the 
  earth, 
  and 
  therefore 
  cosmical 
  rather 
  than 
  terrestrial. 
  Croll's 
  

   famous 
  theory 
  might 
  almost 
  as 
  well 
  be 
  put 
  in 
  the 
  cosmical 
  as 
  in 
  the 
  

   terrestrial 
  class, 
  though 
  it 
  deals 
  soleW 
  with 
  the 
  earth. 
  

  

  A. 
  It 
  has 
  been 
  suggested 
  that 
  the 
  solar 
  system, 
  in 
  its 
  known 
  swift 
  

   passage 
  through 
  space, 
  traverses 
  regions 
  of 
  different 
  temperature, 
  

  

  