﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  lv 
  

  

  proportions 
  of 
  30, 
  50, 
  and 
  even 
  80 
  or 
  85 
  per 
  cent. 
  : 
  and, 
  what 
  to 
  me 
  

   was 
  unexpected, 
  it 
  appears 
  that 
  from 
  the 
  lower 
  to 
  the 
  middle 
  Oolites 
  

   the 
  community 
  or 
  passage 
  of 
  species 
  is 
  in 
  larger 
  proportion 
  than 
  it 
  

   is 
  between 
  some 
  of 
  the 
  minor 
  subdivisions 
  themselves 
  ; 
  for, 
  of 
  178 
  

   inferred 
  Cornbrash 
  species, 
  73, 
  or 
  nearly 
  41 
  per 
  cent., 
  pass 
  upward; 
  

   while, 
  on 
  the 
  same 
  principle, 
  of 
  151 
  species 
  of 
  the 
  KeHoway 
  rock, 
  74 
  

   species, 
  or 
  about 
  49 
  per 
  cent., 
  are 
  found 
  in 
  older 
  formations. 
  Of 
  

   152 
  known 
  Cornbrash 
  species, 
  43, 
  or 
  28 
  per 
  cent., 
  pass 
  upward. 
  

   From 
  the 
  Coral 
  Kag 
  to 
  the 
  Kimeridge 
  clay, 
  of 
  168 
  inferred 
  species, 
  

   20, 
  or 
  only 
  about 
  12 
  per 
  cent., 
  pass 
  upward 
  ; 
  while 
  it 
  is 
  worthy 
  of 
  

   remark 
  that 
  from 
  the' 
  Upper 
  to 
  the 
  Middle 
  Oolite, 
  of' 
  60 
  species 
  that 
  

   lived 
  in 
  the 
  period 
  of 
  the 
  Kimmeridge 
  clay, 
  20, 
  or 
  about 
  33 
  per 
  cent., 
  

   are 
  also 
  found 
  below. 
  The 
  Coral 
  Rag 
  species 
  representing 
  the 
  differ- 
  

   ence 
  of 
  percentage 
  had 
  migrated 
  or 
  become 
  extinct. 
  

  

  The 
  greater 
  inferences 
  that 
  may 
  be 
  drawn 
  from 
  this 
  general 
  survey 
  

   of 
  the 
  phenomena 
  are 
  : 
  — 
  

  

  1. 
  That 
  there 
  are 
  13 
  species 
  common 
  to 
  the 
  uppermost 
  part 
  of 
  the 
  

   Upper 
  Lias 
  and 
  the 
  Oolite. 
  The 
  break 
  is 
  by 
  no 
  means 
  complete. 
  

  

  2. 
  That 
  progressively 
  from 
  the 
  lowest 
  to 
  the 
  highest 
  Oolitic 
  for- 
  

   mations, 
  large 
  percentages 
  of 
  species 
  pass 
  upwards 
  without 
  any 
  

   approach 
  to 
  a 
  total 
  break 
  either 
  in 
  the 
  whole 
  or 
  in 
  individual 
  groups, 
  

   excepting 
  in 
  the 
  instance 
  of 
  the 
  Cephalopoda 
  of 
  the 
  Inferior 
  and 
  the 
  

   Great 
  Oolite. 
  

  

  3. 
  That 
  species 
  often 
  disappear 
  from 
  an 
  intermediate 
  formation 
  to 
  

   reappear 
  in 
  a 
  higher 
  one, 
  and 
  the 
  principle 
  of 
  migration 
  and 
  return 
  

   is 
  thus 
  established. 
  

  

  4. 
  That, 
  notwithstanding 
  migration 
  and 
  passage 
  of 
  species, 
  it 
  

   might 
  perhaps 
  be 
  safely 
  inferred 
  that 
  between 
  the 
  lowest 
  and 
  the 
  

   highest 
  Oolitic 
  formation 
  many 
  forms 
  had 
  disappeared 
  altogether, 
  so 
  

   greatly 
  are 
  their 
  numbers 
  diminished 
  in 
  the 
  higher 
  strata. 
  

  

  5. 
  It 
  seems 
  not 
  unlikely 
  that, 
  notwithstanding 
  the 
  large 
  commu- 
  

   nity 
  of 
  species, 
  the 
  succession 
  of 
  the 
  Oolitic 
  formations 
  is 
  not 
  un- 
  

   broken 
  by 
  minor 
  gaps 
  unrepresented 
  by 
  strata, 
  of 
  the 
  kind 
  exjDlained 
  

   in 
  my 
  last 
  Address. 
  We 
  are 
  aided 
  m 
  this 
  conclusion 
  by 
  a 
  considera- 
  

   tion 
  of 
  the 
  physical 
  conditions 
  under 
  which 
  the 
  Oolitic 
  rocks 
  pre- 
  

   sent 
  themselves. 
  Thus 
  the 
  Inferior 
  Oolite 
  attains 
  its 
  maximum 
  

   development 
  near 
  Cheltenham, 
  where 
  it 
  can 
  be 
  subdivided 
  at 
  least 
  

   into 
  three 
  parts. 
  Passing 
  north, 
  the 
  two 
  lower 
  divisions, 
  each 
  more 
  or 
  

   less 
  characterized 
  by 
  its 
  own 
  fossils, 
  disappear, 
  and 
  the 
  Eagstone 
  

   north-east 
  of 
  Cheltenham 
  lies 
  directly 
  upon 
  the 
  Lias, 
  apparently 
  as 
  

   conformably 
  as 
  if 
  it 
  formed 
  its 
  true 
  and 
  immediate 
  successor, 
  while 
  

   at 
  Dundry 
  the 
  equivalents 
  of 
  the 
  upper 
  freestones 
  and 
  ragstones 
  (the 
  

   lower 
  beds 
  being 
  absent) 
  lie 
  directly 
  on 
  the 
  exceedingly 
  thin 
  repre- 
  

   sentative 
  of 
  the 
  Upper 
  Lias. 
  In 
  Dorsetshire, 
  on 
  the 
  coast, 
  the 
  series 
  

   is 
  again 
  perfect, 
  though 
  thin. 
  Near 
  Chipping 
  Norton, 
  in 
  Oxford- 
  

   shire, 
  the 
  Inferior 
  Oolite 
  disappears 
  altogether, 
  and 
  the 
  Great 
  Oolite, 
  

   having 
  first 
  overlapped 
  the 
  Fuller's 
  Earth, 
  passes 
  across 
  the 
  Inferior 
  

   Oolite, 
  and 
  in 
  its 
  turn 
  seems 
  to 
  lie 
  on 
  the 
  Upper 
  Lias 
  with 
  a 
  regu- 
  

   larity 
  as 
  perfect 
  as 
  if 
  no 
  formation 
  anywhere 
  in 
  the 
  neighbourhood 
  

   came 
  between 
  them. 
  In 
  Yorkshire 
  the 
  changed 
  type 
  of 
  the 
  Inferior 
  

  

  