﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  105 
  

  

  Cornbrash 
  fauna 
  in 
  Oxfordshire, 
  naming 
  74 
  species 
  — 
  and 
  associated 
  

   with 
  it 
  153 
  Great-Oolite 
  species 
  from 
  the 
  Oxford 
  area, 
  50 
  of 
  which 
  

   are 
  also 
  Cornbrash 
  and 
  mostly 
  from 
  Islip. 
  The 
  fauna 
  distri- 
  

   buted 
  through 
  the 
  Cornbrash 
  of 
  five 
  chief 
  localities 
  noticed 
  in 
  the 
  

   Rutland 
  memoir 
  is 
  most 
  variable 
  (Midland 
  Oolites). 
  It 
  numbers 
  

   30 
  genera 
  and 
  68 
  species 
  at 
  Stilton, 
  36 
  genera 
  and 
  64 
  species 
  at 
  

   Rushden, 
  16 
  genera 
  and 
  32 
  species 
  at 
  Oundle, 
  18 
  genera 
  and 
  23 
  

   species 
  at 
  Bourn, 
  and 
  15 
  genera 
  and 
  19 
  species 
  at 
  Manthorp. 
  The 
  

   Yorkshire 
  type 
  is 
  far 
  more 
  prolific. 
  Leckenby, 
  in 
  his 
  paper 
  on 
  

   the 
  Cornbrash 
  of 
  Yorkshire, 
  enumerates 
  no 
  less 
  than 
  70 
  genera 
  

   and 
  135 
  species. 
  As 
  everywhere 
  else, 
  the 
  Cephalopoda 
  are 
  re- 
  

   duced 
  to 
  a 
  minimum, 
  only 
  1 
  species 
  of 
  Ammonite 
  {A. 
  Herveyi), 
  

   1 
  Beleninite 
  (B. 
  tomatilis), 
  and 
  1 
  Nautilus 
  (N. 
  heojagonus) 
  being 
  

   known. 
  The 
  Oxford 
  deposit 
  shows 
  the 
  same 
  fact. 
  Table 
  XIY. 
  shows 
  

   the 
  fauna 
  of 
  the 
  two 
  horizons 
  for 
  the 
  Midland 
  districts 
  ; 
  Yorkshire 
  

   is 
  added 
  for 
  comparison 
  here, 
  and 
  may 
  induce 
  research 
  into 
  the 
  

   causes 
  which 
  led 
  to 
  its 
  great 
  development, 
  change 
  of 
  character, 
  

   and 
  greatly 
  increased 
  fauna 
  JN". 
  of 
  the 
  Humber, 
  and 
  the 
  sudden 
  

   change 
  from 
  the 
  sandy 
  Upper 
  Estuarine 
  and 
  plant-bearing 
  beds 
  to 
  

   a 
  calcareous 
  zone 
  about 
  5 
  feet 
  thick 
  with 
  so 
  rich 
  a 
  fauna. 
  

  

  The 
  late 
  sub-Wealden 
  exploration 
  has 
  done 
  much 
  for 
  our 
  know- 
  

   ledge 
  of 
  the 
  Upper 
  Jurassic 
  rocks 
  of 
  Britain 
  ; 
  it 
  has 
  especially 
  

   altered 
  our 
  views 
  as 
  to 
  the 
  nature, 
  subdivision, 
  and 
  thickness 
  of 
  the 
  

   Kimmeridge 
  Clay 
  of 
  England. 
  

  

  In 
  1875, 
  the 
  Rev. 
  J. 
  E. 
  Blake, 
  M.A., 
  read 
  before 
  our 
  Society 
  his 
  

   paper 
  " 
  On 
  the 
  Kimmeridge 
  Clay 
  of 
  England." 
  Since 
  the 
  memorable 
  

   memoir 
  of 
  Dr. 
  Eitton 
  on 
  the 
  strata 
  below 
  the 
  Chalk, 
  nothing 
  seems 
  

   to 
  have 
  been 
  done 
  with 
  the 
  beds 
  of 
  the 
  Oolitic 
  group 
  immediately 
  

   above 
  the 
  Corallian 
  beds. 
  Damon, 
  in 
  his 
  * 
  Guide 
  to 
  the 
  Weymouth 
  

   District,' 
  devotes 
  some 
  space 
  to 
  this 
  member 
  of 
  the 
  Upper 
  Oolite 
  ; 
  

   and 
  the 
  late 
  sub-Wealden 
  exploration 
  did 
  much 
  towards 
  adding 
  to 
  

   our 
  knowledge 
  of 
  the 
  thickness 
  and 
  fossil 
  contents 
  of 
  the 
  Kimmeridge 
  

   beds 
  of 
  Sussex 
  below 
  the 
  Wealden 
  series. 
  On 
  the 
  continent 
  

   close 
  study 
  and 
  analysis 
  has 
  resulted 
  in 
  separating 
  the 
  Kimmeridge- 
  

   clay 
  group 
  into 
  3 
  zones 
  : 
  — 
  the 
  lowest, 
  that 
  of 
  Astarte 
  supracorcdlina, 
  

   or 
  the 
  Astartian 
  zone 
  ; 
  the 
  second 
  or 
  middle, 
  that 
  of 
  Pterocera 
  Oceani, 
  

   or 
  the 
  Pterocerian 
  zone 
  ; 
  the 
  third 
  or 
  upper 
  is 
  either 
  referred 
  to 
  or 
  

   included 
  in 
  the 
  zone 
  of 
  Trigonia 
  gibhosa, 
  in 
  the 
  Portland 
  strata, 
  

   or 
  separated 
  as 
  the 
  zone 
  of 
  Eocogyra 
  virgula, 
  or 
  the 
  Yirgulian 
  

   zone. 
  The 
  names 
  Astartian 
  and 
  Pterocerian 
  have 
  much 
  signi- 
  

   ficance, 
  as 
  bearing 
  upon 
  the 
  correlation 
  with 
  the 
  same 
  beds 
  of 
  

   the 
  continent 
  — 
  not 
  that 
  we 
  must 
  lay 
  too 
  much 
  stress 
  upon 
  a 
  few 
  or 
  

   certain 
  species 
  as 
  definitely 
  fixing 
  the 
  horizons 
  of 
  two 
  areas 
  widely 
  

   separated. 
  

  

  In 
  the 
  Kimmeridge 
  Clay 
  this 
  is 
  to 
  be 
  observed 
  and 
  borne 
  in 
  

   mind. 
  Although, 
  broadly 
  speaking, 
  certain 
  portions 
  are 
  recognized 
  

   and 
  separated 
  by 
  their 
  general 
  and, 
  at 
  times, 
  special 
  assemblage 
  of 
  

   fossils, 
  yet 
  many 
  that 
  are 
  in 
  one 
  locality 
  and 
  portion 
  highly 
  cha- 
  

  

  