﻿736 
  SEARLES 
  V. 
  WOOD 
  ON 
  THE 
  NEWER 
  

  

  Whatever 
  effect 
  upon 
  climate 
  geographical 
  changes 
  may 
  produce 
  

   (and 
  they 
  are, 
  it 
  is 
  by 
  all 
  conceded, 
  considerable) 
  it 
  must 
  be 
  very 
  slow 
  : 
  

   but 
  though 
  some 
  refrigeration 
  had 
  been 
  proceeding 
  throughout 
  the 
  

   Older 
  Pliocene 
  period 
  and 
  the 
  early 
  part 
  of 
  the 
  Newer, 
  its 
  culmina- 
  

   tion 
  in 
  the 
  great 
  glaciation 
  appears 
  to 
  have 
  been 
  rapid. 
  It 
  is, 
  

   moreover, 
  inconceivable 
  by 
  me 
  that 
  changes 
  so 
  great 
  as 
  to 
  have 
  

   given 
  rise 
  to 
  this 
  should 
  have 
  passed 
  away, 
  and 
  again 
  recurred 
  in 
  

   the 
  short 
  interval 
  between 
  the 
  major 
  and 
  minor 
  glaciations. 
  The 
  

   insignificant 
  depression 
  of 
  England 
  traced 
  in 
  Stage 
  VI. 
  could 
  have 
  

   had 
  no 
  appreciable 
  effect 
  upon 
  the 
  climate 
  of 
  the 
  northern 
  hemi- 
  

   sphere. 
  Changes 
  in 
  land 
  and 
  water, 
  if 
  their 
  sufficiency 
  under 
  any 
  

   view 
  of 
  the 
  case 
  to 
  produce 
  a 
  glaciation 
  were 
  conceded, 
  must 
  have 
  

   been 
  of 
  an 
  extent 
  great 
  enough 
  to 
  have 
  altered 
  the 
  distribution 
  of 
  

   land 
  and 
  sea 
  generally 
  over 
  the 
  northern 
  hemisphere 
  ; 
  and 
  it 
  is, 
  as 
  

   I- 
  have 
  said, 
  inconceivable 
  that 
  these 
  should, 
  after 
  giving 
  rise 
  to 
  the 
  

   great 
  glaciation, 
  have 
  changed 
  to 
  those 
  which 
  restored 
  the 
  climate 
  

   of 
  the 
  Upper 
  Crag 
  during 
  the 
  Cy/)vna-formation, 
  and 
  again 
  changed 
  

   to 
  those 
  giving 
  rise 
  to 
  the 
  arctic 
  climate 
  of 
  the 
  minor 
  glaciation 
  — 
  a 
  

   double 
  coincidence 
  — 
  within 
  the 
  short 
  duration, 
  geologically 
  speaking, 
  

   of 
  the 
  Newer 
  Pliocene 
  period. 
  

  

  It 
  is 
  therefore, 
  it 
  seems 
  to 
  me, 
  only 
  a 
  variation 
  in 
  the 
  heat 
  of 
  the 
  

   sun 
  to 
  which 
  the 
  glaciations 
  can 
  be 
  attributed. 
  When 
  I 
  expressed 
  

   that 
  opinion 
  in 
  a 
  review 
  of 
  the 
  climate 
  controversy 
  in 
  the 
  ' 
  Geological 
  

   Magazine' 
  for 
  1876 
  (p. 
  451), 
  no 
  satisfactory 
  cause 
  for 
  this 
  variation 
  

   had 
  been 
  suggested 
  ; 
  but 
  Dr. 
  C. 
  W. 
  Siemens 
  has 
  now 
  advanced 
  the 
  

   theory 
  that 
  the 
  heat 
  of 
  the 
  sun 
  is 
  maintained 
  by 
  the 
  combustion 
  of 
  

   gases 
  diffused 
  in 
  the 
  medium 
  through 
  which 
  it 
  moves, 
  and 
  which 
  

   are 
  drawn 
  in 
  at 
  the 
  polar, 
  and, 
  after 
  combustion, 
  returned 
  by 
  centri- 
  

   fugal 
  force 
  from 
  the 
  equatorial 
  parts 
  of 
  the 
  sun 
  into 
  space. 
  If 
  this 
  

   theory 
  should 
  prove 
  well 
  founded, 
  it 
  would 
  furnish 
  an 
  explanation 
  

   of 
  this 
  variation 
  in 
  the 
  sun's 
  heat, 
  since 
  the 
  quantity 
  of 
  diffused 
  

   gases 
  may 
  vary 
  in 
  different 
  parts 
  of 
  the 
  medium 
  through 
  which 
  the 
  

   sun 
  moves, 
  and 
  the 
  resulting 
  combustion 
  vary 
  accordingly. 
  

  

  Postscript. 
  

  

  After 
  the 
  publication 
  of 
  the 
  first 
  part 
  of 
  this 
  memoir 
  (Q. 
  J. 
  G. 
  S. 
  vol. 
  

   xxxvi.)I 
  was 
  anxious 
  to 
  reexamine 
  the 
  cliffs 
  of 
  Easton-Bavent, 
  South- 
  

   wold, 
  andDunwich(in 
  the 
  north 
  part 
  of 
  Sheet 
  49); 
  because, 
  according 
  

   to 
  the 
  view 
  which 
  I 
  had 
  there 
  advanced, 
  these 
  cliffs 
  are 
  sections 
  of 
  the 
  

   southern 
  portion 
  of 
  that 
  least 
  submerged 
  area, 
  comprising 
  allEast 
  Nor- 
  

   folk 
  and 
  North-east 
  Suffolk, 
  which 
  earliest 
  became 
  land, 
  and 
  appears 
  

   to 
  me 
  to 
  have 
  emerged 
  up 
  to 
  and 
  above 
  its 
  present 
  level 
  b) 
  r 
  the 
  time 
  

   when 
  the 
  ice 
  of 
  the 
  Chalky 
  Clay 
  began 
  to 
  retire 
  from 
  East 
  Anglia 
  ; 
  

   and 
  when 
  all 
  to 
  the 
  south 
  and 
  west 
  of 
  this 
  (except 
  so 
  far 
  as 
  the 
  

   ice 
  extended 
  and 
  kept 
  out 
  the 
  sea) 
  still 
  continued 
  submerged 
  up 
  to 
  

   those 
  heights 
  increasing 
  southwards 
  and 
  westwards 
  proportionally 
  

   to 
  the 
  original 
  increment 
  of 
  depression 
  which 
  I 
  traced 
  in 
  that 
  part 
  

   of 
  the 
  memoir 
  as 
  indicated 
  by 
  the 
  height 
  above 
  O.D. 
  attained 
  by 
  the 
  

   junction 
  of 
  the 
  gravel 
  c 
  with 
  the 
  Chalky 
  Clay 
  overlying 
  it 
  ; 
  and 
  I 
  

   succeeded, 
  though 
  with 
  some 
  difficulty, 
  in 
  doing 
  so. 
  

  

  

  