﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  

  

  225 
  

  

  Dimyaria. 
  — 
  26 
  genera 
  and 
  55 
  species 
  occur, 
  42 
  of 
  which 
  are 
  

   strictly 
  Portlandian. 
  10 
  species 
  come 
  direct 
  from 
  the 
  Kimmeridge 
  

   Clay 
  ; 
  they 
  are 
  named 
  under 
  the 
  Kimmeridge 
  analysis 
  ; 
  the 
  re- 
  

   maining 
  3 
  are 
  Corallian. 
  As 
  in 
  the 
  Monomyaria, 
  no 
  species 
  pass 
  

   above 
  the 
  Portland 
  rocks. 
  The 
  genera 
  Trigonia, 
  Lucina, 
  and 
  Phola- 
  

   domya 
  play 
  an 
  important 
  part 
  in 
  the 
  Upper 
  Jurassic 
  rocks. 
  

  

  Gasteropoda. 
  — 
  As 
  we 
  have 
  seen 
  in 
  the 
  Oxford 
  Clay, 
  the 
  Corallian 
  

   beds, 
  and 
  the 
  Kimmeridge 
  Clay, 
  so 
  now 
  in 
  the 
  Portland, 
  the 
  species 
  

   all 
  belong 
  almost 
  entirely 
  to 
  their 
  own 
  special 
  horizons, 
  Turritella 
  

   minuta 
  being 
  the 
  only 
  species 
  said 
  to 
  be 
  common 
  to 
  the 
  Kimme- 
  

   ridge 
  and 
  Portland 
  out 
  of 
  the 
  10 
  genera 
  and 
  19 
  species 
  occurring. 
  

  

  Cephalopoda. 
  Ammonites. 
  — 
  11 
  species 
  occur, 
  and 
  7 
  are 
  Portlan- 
  

   dian 
  only 
  ; 
  they 
  are 
  Am. 
  boloniensis, 
  Am. 
  giganteus, 
  Am. 
  gigas, 
  Am. 
  

   Gravesianus, 
  Am. 
  ireus, 
  Am. 
  pectinatus, 
  Am. 
  pseudo-gigas. 
  

  

  The 
  4 
  species 
  uniting 
  the 
  Kimmeridge 
  and 
  Portland 
  beds 
  are 
  Am. 
  

   triplex, 
  Am. 
  triplicatus, 
  Am. 
  hector, 
  and 
  Am, 
  biplex 
  ; 
  all 
  the 
  species 
  

   disappear 
  with 
  the 
  close 
  of 
  the 
  Upper 
  Jurassic 
  Period. 
  The 
  genus 
  

   Perisphinctes 
  is 
  well 
  represented 
  among 
  the 
  Portland 
  Ammonites. 
  

  

  Nautili. 
  — 
  None 
  known. 
  

  

  Belemnites. 
  — 
  None 
  known. 
  

  

  Teuthidoe. 
  — 
  None 
  known. 
  

  

  Table 
  XLII. 
  — 
  Showing 
  the 
  Numerical 
  and 
  Stratigraphical 
  Value 
  

   of 
  the 
  whole 
  of 
  the 
  Jurassic 
  Mollusca. 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  t> 
  

  

  

  

  

  

  

  

  

  

  

  

  M 
  

  

  

  

  a 
  

  

  

  Classes. 
  

  

  IB 
  

  

  a 
  

  

  ►3 
  

   u 
  

  

  CD 
  

  

  * 
  

  

  03 
  

   CD 
  

  

  fa 
  

  

  $ 
  

  

  u 
  

  

  CD 
  

  

  "o 
  

  

  

  

  U 
  

   O 
  

  

  'u 
  

   J© 
  

  

  1 
  

  

  CO 
  

  

  38 
  

  

  © 
  

  

  O 
  

  

  CD 
  

  

  CD 
  

   U 
  

  

  -6 
  

  

  CD 
  

  

  CO 
  

  

  e 
  

  

  O 
  

  

  O 
  

  

  1 
  

  

  O 
  

  

  Ti 
  

   U 
  

  

  r 
  3 
  

  

  O 
  

  

  CD 
  

  

  bX) 
  

  

  fa 
  

  

  S-l 
  

   CD 
  

  

  a 
  

   1 
  

  

  d 
  

   3 
  

  

  

  O 
  

  

  s 
  

  

  & 
  

  

  1— 
  1 
  

  

  3 
  

   ft 
  

  

  u 
  

  

  3 
  

  

  £ 
  

  

  

  

  

  

  CD 
  

  

  M 
  

  

  O 
  

  

  

  

  

  

  M 
  

  

  

   Ph 
  

  

  JBrachiopoda 
  

  

  1 
  

   30 
  

  

  1 
  4 
  

  

  7 
  4 
  

  

  1 
  1 
  

  

  47 
  

  

  1 
  

  

  90 
  

  

  4 
  

   1 
  4 
  

  

  26 
  

  

  3 
  

  

  1 
  

  

  4 
  

   I 
  9 
  

  

  5 
  

   1 
  

  

  5 
  

   1 
  

  

  7 
  

   21 
  

  

  4 
  

   1 
  

  

  3 
  

   3 
  

  

  

  Monomyaria 
  

  

  1 
  8 
  

   1 
  1 
  4 
  

  

  60 
  

  

  1 
  3 
  

   32 
  

  

  1 
  5 
  

  

  9 
  

   1 
  5 
  

  

  1 
  6 
  

   80 
  

  

  9 
  

  

  24 
  

  

  1 
  1 
  

  

  5 
  5 
  

  

  28 
  

  

  26 
  

  

  1 
  4 
  

  

  58 
  

  

  1 
  1 
  

  

  42 
  

  

  9 
  

   1 
  9 
  

  

  

  

  36 
  

   139 
  

  

  34 
  

   108 
  

  

  25 
  

   69 
  

  

  4 
  7 
  

   236 
  

  

  22 
  

   5 
  1 
  

  

  40 
  

   185 
  

  

  1 
  9 
  

  

  3 
  3 
  

  

  33 
  

  

  98 
  

  

  1 
  8 
  

   5 
  7 
  

  

  21 
  

  

  48 
  

  

  29 
  

  

  26 
  

  

  58 
  

  

  26 
  

  

  5 
  6 
  

  

  

  

  4 
  1 
  

   226 
  

  

  27 
  

   13 
  6 
  

  

  1 
  9 
  

   5 
  5 
  

  

  41 
  

   240 
  

  

  1 
  

  

  40 
  

   247 
  

  

  4 
  3 
  

  

  20 
  

   28 
  

  

  1 
  

   1 
  9 
  

  

  1 
  

   1 
  7 
  

  

  2 
  1 
  

  

  67 
  

  

  1 
  2 
  

   23 
  

  

  1 
  

   1 
  9 
  

  

  

  Ammonites 
  

  

  1 
  7 
  3 
  

  

  1 
  

   5 
  4 
  

  

  7 
  9 
  

  

  1 
  

   4 
  2 
  

  

  6 
  

  

  7 
  

  

  1 
  

   2 
  

  

  B 
  

  

  4 
  1 
  

  

  4 
  6 
  

  

  2 
  1 
  

  

  3 
  1 
  

  

  1 
  1 
  

  

  

  Nautili 
  

  

  1 
  

   6 
  

  

  4 
  

  

  3 
  

  

  1 
  

   6 
  

  

  

  3 
  

  

  

  1 
  

  

  2 
  

  

  

  1 
  

   1 
  

  

  

  

  

  Belemnites 
  

  

  1 
  

   21 
  

  

  27 
  

  

  34 
  

  

  1 
  6 
  

  

  3 
  

  

  3 
  

  

  

  

  3 
  

  

  1 
  3 
  

  

  4 
  

  

  8 
  

  

  

  

  Teuthidae 
  

  

  J 
  

  

  1 
  

  

  2 
  

  

  

  

  

  

  

  

  2 
  

   2 
  

  

  

  ! 
  

  

  

  Total 
  

  

  1 
  9 
  

  

  7 
  1 
  S 
  

  

  9 
  5 
  

   46 
  4 
  

  

  7 
  2 
  

   3 
  2 
  1 
  

  

  1 
  1 
  6 
  

   7 
  3 
  6 
  

  

  a 
  a 
  

  

  BO 
  

  

  10 
  8 
  

   5 
  5 
  1 
  

  

  6 
  1 
  

   1 
  1 
  8 
  

  

  - 
  7 
  

   204 
  

  

  4 
  7 
  

   1 
  60 
  

  

  49 
  

   1 
  6 
  1 
  

  

  74 
  

   26 
  5 
  

  

  5 
  6 
  

   1 
  7 
  A 
  

  

  4 
  

   1 
  7 
  

  

  

  VOL. 
  XXXVIII. 
  

  

  