﻿460 
  Geological 
  Society. 
  

  

  Ice-Age 
  as 
  now, 
  and 
  it 
  is 
  generally 
  agreed 
  that 
  a 
  lowering 
  of 
  

   the 
  present 
  snow-line 
  by 
  1000 
  metres 
  would 
  givo 
  rise 
  to 
  a 
  similar 
  

   lce-Age. 
  The 
  hypothesis 
  that 
  a 
  glaciation 
  of 
  North 
  America 
  

   would 
  raise 
  the 
  temperature 
  of 
  Europe, 
  and 
  vice 
  versa, 
  seems 
  

   to 
  the 
  author 
  physically 
  untenable. 
  The 
  positions 
  and 
  move- 
  

   ments 
  of 
  anticyclones 
  are 
  not 
  generally 
  ruled 
  by 
  the 
  ground 
  

   temperature 
  in 
  our 
  latitudes 
  : 
  they 
  are 
  in 
  most 
  cases 
  eddies 
  formed 
  

   by 
  the 
  air-circulation 
  in 
  general, 
  and 
  in 
  this 
  the 
  greater 
  area 
  and 
  

   receipt 
  of 
  heat 
  by 
  the 
  Equatorial 
  regions 
  must 
  always 
  be 
  a 
  pre- 
  

   ponderating 
  factor. 
  The 
  author 
  considers 
  that 
  the 
  influence 
  of 
  

   the 
  Glacial 
  Period 
  on 
  atmospheric 
  circulation 
  would 
  probably 
  be 
  

   similar 
  to 
  that 
  of 
  a 
  cold 
  winter 
  nowadays. 
  The 
  cyclones 
  would 
  be 
  

   gradually 
  deviated 
  into 
  a 
  more 
  and 
  more 
  southerly 
  track, 
  while 
  an 
  

   anticyclone 
  would 
  be 
  formed 
  in 
  the 
  north, 
  not, 
  however, 
  a 
  stationary 
  

   one, 
  but 
  travelling 
  like 
  a 
  cyclone, 
  only 
  more 
  slowly 
  and 
  irregularly. 
  

   The 
  summer 
  must 
  have 
  been 
  cold 
  and 
  stor^ny, 
  with 
  frequent 
  fogs, 
  

   somewhat 
  like 
  that 
  of 
  Cape 
  Horn 
  or 
  Kerguelen 
  Island 
  at 
  the 
  present 
  

   day. 
  The 
  author 
  considers 
  that 
  Mr. 
  Harmer 
  underrates 
  the 
  effect 
  

   of 
  insolation 
  and 
  overrates 
  that 
  of 
  the 
  winds. 
  ' 
  The 
  temperature 
  

   of 
  the 
  summer 
  only 
  is 
  essential 
  for 
  the 
  phenomenon 
  of 
  glaciation.' 
  

  

  3. 
  ' 
  On 
  the 
  Origin 
  of 
  certain 
  Concretions 
  in 
  the 
  Lower 
  Coal- 
  

   Measurcs.' 
  By 
  H. 
  B. 
  Stocks, 
  Esq., 
  F.I.C., 
  E.C.S. 
  

  

  In 
  certain 
  of 
  the 
  Lower 
  Coal-Measures 
  of 
  Lancashire 
  and 
  York- 
  

   shire 
  and 
  in 
  the 
  ' 
  hard-bed 
  coal/ 
  peculiar 
  concretions 
  known 
  as 
  

   * 
  coal-balls 
  ' 
  occur, 
  which 
  have 
  a 
  considerable 
  interest 
  because 
  they 
  

   contain 
  well-preserved 
  plant-remains. 
  The 
  author's 
  analysis 
  shows 
  

   that 
  they 
  consist 
  mainly 
  of 
  calcium 
  carbonate 
  and 
  iron-pyrites, 
  

   in 
  varying 
  proportions. 
  Carbonate 
  of 
  lime 
  appears 
  to 
  have 
  been 
  

   introduced 
  by 
  osmosis 
  through 
  the 
  cell-walls 
  ; 
  and 
  that 
  it 
  was 
  in- 
  

   troduced 
  in 
  small 
  quantity 
  and 
  under 
  exceptional 
  circumstances 
  

   appears 
  to 
  be 
  proved 
  by 
  the 
  comparative 
  rarity 
  of 
  the 
  concretions 
  

   and 
  their 
  presence 
  in 
  this 
  seam 
  of 
  coal 
  only. 
  During 
  the 
  decay 
  of 
  

   the 
  vegetable 
  matter 
  of 
  which 
  coal 
  is 
  formed, 
  in 
  contact 
  probably 
  

   also 
  with 
  animal 
  matter, 
  some 
  of 
  the 
  organic 
  matter 
  would 
  pass 
  

   into 
  solution 
  in 
  water, 
  causing 
  the 
  absorption 
  of 
  the 
  oxygen 
  in 
  

   solution 
  ; 
  the 
  result 
  of 
  this 
  is 
  that 
  further 
  decay 
  would 
  take 
  place 
  

   under 
  anaerobic 
  conditions. 
  This, 
  occurring 
  in 
  water 
  containing 
  

   sulphates, 
  would 
  give 
  rise 
  to 
  sulphuretted 
  hydrogen 
  and 
  mud 
  

   blackened 
  by 
  the 
  presence 
  of 
  ferrous 
  sulphide, 
  while 
  carbonates 
  

   would 
  also 
  be 
  produced. 
  Experiments 
  were 
  tried 
  (1) 
  on 
  the 
  pre- 
  

   cipitation 
  of 
  carbonate 
  of 
  lime 
  under 
  varying 
  conditions 
  (in 
  presenco 
  

   of 
  organic 
  matter, 
  etc.) 
  ; 
  (2) 
  on 
  the 
  action 
  of 
  salts 
  of 
  lime 
  and 
  of 
  

   iron 
  on 
  wood; 
  and 
  (3) 
  on 
  the 
  action 
  of 
  bacteria 
  on 
  solutions 
  con- 
  

   taining 
  calcium 
  sulphate 
  in 
  solution 
  and 
  ferric 
  oxide 
  in 
  the 
  deposit.. 
  

   In 
  the 
  first 
  series 
  carbonato 
  of 
  lime 
  was 
  deposited 
  in 
  spheres 
  ; 
  in 
  

   the 
  second 
  it 
  was 
  found 
  that 
  iron-salts 
  are 
  preservatives 
  but 
  lime- 
  

   salts 
  are 
  not; 
  and 
  in 
  the 
  third, 
  black 
  mud 
  largely 
  consisting 
  of 
  

   ferrous 
  sulphide 
  was 
  produced, 
  while 
  the 
  calcium 
  sulphate 
  was 
  

   converted 
  into 
  carbonate. 
  It 
  is 
  considered 
  that 
  these 
  experiments 
  

   explain 
  the 
  origin 
  of 
  the 
  ' 
  coal-balls.' 
  

  

  