﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  

  

  153 
  

  

  the 
  Lower 
  Lias 
  ; 
  of 
  these, 
  16 
  species 
  pass 
  to 
  the 
  Middle 
  Lias, 
  and 
  7 
  

   occur 
  in 
  all 
  three 
  divisions. 
  These 
  last 
  are 
  Discina 
  reflexa, 
  Rhyncho- 
  

   nella 
  fur 
  cillata, 
  R. 
  variabilis, 
  Spiriferina 
  rostrata, 
  Thecidium 
  Moorei, 
  

   T. 
  rusticum, 
  and 
  T. 
  triangulare. 
  Rhynchonella 
  is 
  represented 
  by 
  

   64 
  species 
  in 
  the 
  Jurassic 
  rocks, 
  with 
  91 
  appearances. 
  Another 
  

   rich 
  genus 
  is 
  Terebratula, 
  in 
  which 
  67 
  species 
  occur 
  ; 
  and 
  Wald- 
  

   heimia 
  has 
  44. 
  To 
  show 
  their 
  distribution 
  through 
  Jurassic 
  

   time, 
  T 
  append 
  the 
  following 
  short 
  Table 
  (XX.). 
  The 
  remaining 
  

   13 
  genera 
  are 
  very 
  restricted 
  in 
  range, 
  which 
  gives 
  them 
  their 
  chief 
  

   significance. 
  This 
  will 
  be 
  apparent 
  when 
  I 
  construct 
  a 
  general 
  

   Table 
  of 
  the 
  distribution 
  of 
  the 
  Brachiopoda 
  at 
  the 
  close 
  of 
  the 
  

   Jurassic 
  period. 
  

  

  Table 
  XX. 
  

  

  

  JO 
  

  

  © 
  

  

  © 
  

  

  

  

  OS 
  

  

  © 
  

  

  i 
  

  

  u 
  

  

  © 
  

   Q-i 
  

  

  © 
  

  

  'o 
  

   O 
  

  

  .2 
  

  

  "Jh 
  

  

  5-1—1 
  

  

  3 
  

   U 
  

   H 
  

   J 
  00 
  

  

  © 
  

  

  © 
  

  

  

   O 
  

  

  © 
  

  

  © 
  

  

  1 
  

  

  © 
  

   u 
  

   

   ft 
  

  

  | 
  

   

   Q 
  

  

  4^ 
  

   © 
  

   

  

  ""© 
  

  

  W 
  

  

  O 
  

  

  u 
  

  

  O 
  

  

  PS 
  

  

  1 
  

   O 
  

   O 
  

  

  5 
  

  

  © 
  

  

  fcUO 
  

  

  IS 
  

  

  © 
  

  

  a 
  

  

  a 
  

  

  r3 
  

  

  

  

  | 
  

   

  

  P4 
  

   2 
  

   1 
  

   1 
  

  

  i 
  

  

  © 
  

   Ph 
  

   Pw 
  

   eg 
  

  

  ci 
  

  

  85 
  

   64 
  

   91 
  

  

  Terebratula 
  

  

  Waldheimia 
  

  

  Rhynchonella 
  . 
  . 
  . 
  

  

  67 
  

   44 
  

   64 
  

  

  4 
  

   3 
  

   9 
  

  

  10 
  

   13 
  

  

  19 
  

  

  3 
  

  

  3 
  

  

  10 
  

  

  31 
  

   13 
  

   23 
  

  

  5 
  

  

  4 
  

   4 
  

  

  7 
  

   4 
  

   5 
  

  

  4 
  

   

   3 
  

  

  5 
  

   8 
  

   5 
  

  

  3 
  

   3 
  

   3 
  

  

  2 
  

   3 
  

  

  2 
  

  

  7 
  

   6 
  

   3 
  

  

  2 
  

   4 
  

  

  

  

  16 
  

  

  42 
  

  

  16 
  

  

  67 
  

  

  13 
  

  

  16 
  

  

  10 
  

  

  18 
  

  

  9 
  

  

  7 
  

  

  16 
  

  

  6 
  

  

  4 
  

  

  240 
  

  

  Middle 
  Lias. 
  — 
  No 
  less 
  than 
  14 
  genera 
  and 
  74 
  species 
  occur 
  in 
  

   the 
  Middle 
  Lias. 
  The 
  three 
  chief 
  genera 
  in 
  the 
  above 
  Table 
  yield 
  

   42 
  species. 
  Only 
  4 
  species 
  of 
  Rhynchonella 
  pass 
  to 
  the 
  Upper 
  Lias, 
  

   viz. 
  R. 
  furcillata, 
  R. 
  pygmcea, 
  R. 
  variabilis, 
  and 
  R. 
  cynocephala 
  ; 
  none 
  

   to 
  the 
  Inferior 
  Oolite 
  or 
  higher 
  beds. 
  In 
  Terebratula 
  only 
  1 
  species 
  

   ( 
  T. 
  globulina) 
  is 
  common 
  to 
  the 
  Middle 
  and 
  Upper 
  Lias, 
  and 
  none 
  

   out 
  of 
  the 
  known 
  12 
  ranges 
  higher. 
  Waldheimia, 
  according 
  to 
  the 
  

   last 
  reconstruction 
  of 
  the 
  genus, 
  and 
  the 
  removal 
  to 
  it 
  from 
  the 
  genus 
  

   Terebratula 
  of 
  certain 
  forms 
  found 
  to 
  differ 
  essentially 
  from 
  the 
  latter 
  

   in 
  their 
  internal 
  structure, 
  now 
  numbers 
  44 
  species, 
  13 
  of 
  which 
  

   occur 
  in 
  the 
  Lower 
  Lias, 
  13 
  in 
  the 
  Inferior 
  Oolite, 
  and 
  8 
  in 
  the 
  

   Cornbrash 
  ; 
  the 
  remaining 
  species 
  are 
  irregularly 
  distributed 
  through 
  

   the 
  other 
  ten 
  horizons. 
  Terebratula 
  is 
  the 
  genus 
  most 
  largely 
  repre- 
  

   sented 
  in 
  the 
  Jurassic 
  rocks. 
  In 
  the 
  Inferior 
  Oolite 
  31 
  species 
  are 
  

   known, 
  and 
  in 
  the 
  Middle 
  Lias 
  10. 
  The 
  remaining 
  11 
  genera 
  

   average 
  only 
  4 
  species 
  in 
  each. 
  In 
  the 
  Lower 
  Lias 
  4 
  species 
  are 
  

   known, 
  in 
  the 
  Middle 
  Lias 
  10, 
  and 
  in 
  the 
  Upper 
  Lias 
  only 
  3. 
  

  

  Lajiellibranchiata. 
  — 
  Few 
  perhaps 
  would 
  believe, 
  unless 
  they 
  

   paid 
  close 
  attention 
  to 
  the 
  palaeontology 
  of 
  the 
  Jurassic 
  rocks, 
  that 
  

   no 
  less 
  than 
  1368 
  species 
  of 
  Lamellibranchiate 
  Mollusca 
  occur 
  in 
  

   the 
  13 
  divisions. 
  The 
  Lias 
  alone 
  has 
  yielded 
  65 
  genera 
  and 
  457 
  

  

  