﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  U 
  

  

  species 
  graduate 
  upwards 
  from 
  one 
  division 
  to 
  another, 
  in 
  numbers 
  

   varying 
  from 
  about 
  20 
  to 
  50 
  per 
  cent. 
  The 
  only 
  sound 
  exception 
  to 
  

   this 
  is 
  where 
  a 
  sudden 
  lithological 
  break 
  takes 
  place 
  between 
  the 
  

   Marlstone 
  and 
  the 
  Upper 
  Lias, 
  in 
  which 
  case 
  only 
  b\ 
  per 
  cent, 
  pass 
  

   onwards 
  into 
  the 
  newer 
  formation. 
  Further, 
  it 
  must 
  be 
  remem- 
  

   bered 
  that, 
  when 
  the 
  Liassic 
  fossils 
  were 
  named, 
  the 
  tendency 
  among 
  

   palaeontologists 
  to 
  extreme 
  subdivision 
  of 
  species 
  was 
  so 
  strong, 
  that 
  

   there 
  can 
  be 
  little 
  doubt 
  that 
  trifling 
  varieties 
  have 
  often 
  been 
  exalted 
  

   into 
  individual 
  species, 
  and 
  the 
  numbers 
  common 
  to 
  more 
  than 
  one 
  

   subdivision 
  are 
  doubtless 
  larger 
  than 
  I 
  have 
  stated. 
  

  

  Considering 
  that 
  no 
  actual 
  unconformity 
  is 
  known 
  from 
  the 
  bottom 
  

   of 
  the 
  Lower 
  to 
  the 
  top 
  of 
  the 
  Upper 
  Lias, 
  some 
  geologists 
  may 
  

   find 
  it 
  difficult 
  to 
  perceive 
  why 
  there 
  should 
  be 
  even 
  such 
  partial 
  breaks 
  

   in 
  the 
  succession 
  of 
  species, 
  except 
  on 
  the 
  hypothesis 
  that 
  a 
  large 
  

   proportion 
  of 
  the 
  old 
  species 
  were 
  in 
  each 
  case 
  destroyed 
  at 
  the 
  close 
  

   of 
  one 
  formation 
  and 
  replaced 
  by 
  the 
  creation 
  of 
  new 
  forms 
  when 
  

   the 
  succeeding 
  formation 
  began. 
  But 
  I 
  cannot 
  accept 
  this 
  well- 
  

   worn 
  hypothesis 
  ; 
  and 
  in 
  this 
  matter 
  I 
  incline 
  to 
  the 
  idea 
  that, 
  con- 
  

   sidering 
  the 
  frequent 
  large 
  percentages 
  of 
  passage 
  (ranging 
  as 
  high 
  

   as 
  50 
  per 
  cent.), 
  we 
  are 
  justified 
  in 
  supposing 
  that 
  migration 
  of 
  what 
  

   were 
  old 
  species 
  here 
  into 
  new 
  areas 
  elsewhere, 
  and 
  of 
  certain 
  older 
  

   species 
  from 
  other 
  areas 
  into 
  ours, 
  may 
  account 
  for 
  the 
  very 
  incom- 
  

   plete 
  breaks 
  in 
  the 
  succession 
  of 
  Liassie 
  life 
  in 
  England, 
  more 
  espe- 
  

   cially 
  if, 
  as 
  may 
  have 
  often 
  been 
  the 
  case, 
  there 
  were 
  occasional 
  

   pauses 
  in 
  the 
  deposition 
  of 
  the 
  strata. 
  An 
  analysis, 
  such 
  as 
  I 
  now 
  

   attempt, 
  in 
  other 
  regions 
  of 
  Europe 
  will 
  alone 
  help 
  to 
  clear 
  up 
  the 
  

   question. 
  

  

  Passing 
  upwards 
  in 
  the 
  secondary 
  series 
  we 
  come 
  to 
  the 
  Oolitic 
  

   rocks, 
  the 
  minor 
  and 
  greater 
  divisions 
  of 
  which 
  are 
  singularly 
  well 
  

   established. 
  

  

  Oolitic 
  strata. 
  — 
  First 
  comes 
  the 
  Inferior 
  Oolite, 
  which, 
  both 
  on 
  

   pakeontological 
  and 
  physical 
  data, 
  has 
  been 
  divided 
  at 
  Cheltenham 
  

   into 
  the 
  following 
  minor 
  zones 
  in 
  descending 
  order 
  : 
  — 
  

  

  f 
  Upper 
  Trigonia-grit. 
  

   Ragstone, 
  zone 
  of 
  A. 
  Parkinsoni 
  < 
  Gryphite 
  grit. 
  

  

  [ 
  Lower 
  Trigonia-grit. 
  

   Upper 
  Freestones, 
  zone 
  of 
  A. 
  ffaniphresianus. 
  

  

  {Oolite 
  marl. 
  

   Lower 
  freestones. 
  

   Pea-grit. 
  

  

  It 
  is 
  interesting 
  to 
  find, 
  in 
  the 
  first 
  place, 
  that 
  there 
  is 
  no 
  com- 
  

   plete 
  break 
  in 
  succession 
  between 
  the 
  Upper 
  Lias 
  and 
  the 
  Inferior 
  

   Oolite, 
  13 
  species/or 
  about 
  21 
  per 
  cent., 
  passing 
  from 
  the 
  lower 
  to 
  

   the 
  higher 
  formation. 
  It 
  would 
  also 
  repay 
  the 
  trouble 
  were 
  any 
  

   one 
  to 
  analyze 
  the 
  palaaontological 
  differences 
  between 
  the 
  sub- 
  

   divisions 
  of 
  the 
  Inferior 
  Oolite, 
  but 
  these 
  differences 
  are 
  so 
  analogous 
  

   to 
  those 
  of 
  the 
  Lower 
  Lias, 
  that 
  I 
  forbear 
  to 
  state 
  them 
  at 
  present. 
  

   The 
  percentages 
  of 
  Mollusca 
  common 
  to 
  the 
  various 
  subdivisions 
  are 
  

   large 
  ; 
  and, 
  therefore, 
  though 
  it 
  would 
  be 
  instructive 
  to 
  show 
  the 
  

  

  