﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  1 
  33 
  

  

  The 
  Department 
  oe 
  the 
  Lower 
  Charente. 
  — 
  D'Orbigny 
  in 
  1852, 
  

   and 
  Manes 
  (' 
  Statistique 
  Geologique 
  cle 
  la 
  Charente 
  Inferieure,' 
  1855) 
  

   have 
  studied 
  the 
  rocks 
  of 
  this 
  department. 
  Manes 
  divides 
  them 
  into 
  

   4 
  groups 
  : 
  — 
  

  

  1. 
  Portlandian 
  280 
  feet 
  in 
  4 
  subdivisions. 
  

  

  2. 
  Kimmeridgian... 
  260 
  „ 
  in 
  2 
  „ 
  

  

  3. 
  Corallian 
  330 
  „ 
  in 
  2 
  „ 
  

  

  4. 
  Oxfordian 
  550 
  ,, 
  in 
  2 
  „ 
  

  

  Mr. 
  Blake 
  questions 
  whether 
  the 
  rocks 
  in 
  the 
  Lower 
  Charente 
  

   are 
  different 
  from 
  those 
  of 
  the 
  Upper. 
  In 
  the 
  Rochelle 
  district 
  

   things 
  are 
  changed, 
  and 
  we 
  are 
  studying 
  the 
  development 
  in 
  a 
  new 
  

   basin 
  ; 
  and, 
  as 
  the 
  author 
  states, 
  we 
  find 
  that 
  out 
  of 
  222 
  Corallian 
  

   species 
  named 
  by 
  D'Orbigny 
  in 
  his 
  ' 
  Prodrome,' 
  no 
  fewer 
  than 
  90, 
  or 
  

   more 
  than 
  40 
  per 
  cent., 
  are 
  peculiar, 
  while 
  only 
  80 
  occur 
  in 
  any 
  of 
  

   the 
  localities 
  yet 
  studied. 
  Here, 
  again, 
  I 
  must 
  refer 
  to 
  the 
  careful 
  

   study 
  of 
  these 
  beds 
  and 
  their 
  fossil 
  contents 
  by 
  Mr. 
  Blake. 
  

  

  III. 
  Normandy 
  with 
  Orne-and-Sarthe. 
  

  

  In 
  the 
  department 
  of 
  the 
  Orne-and-Sarthe 
  the 
  Upper 
  Jurassic 
  

   rocks 
  are 
  only 
  feebly 
  developed 
  along 
  the 
  strip 
  running 
  from 
  Le 
  

   Mans 
  in 
  the 
  south 
  to 
  Normandy. 
  Hebert 
  in 
  1857 
  ( 
  ; 
  Les 
  mers 
  

   anciennes 
  et 
  leur 
  rivages 
  dans 
  le 
  bassin 
  de 
  Paris. 
  Part 
  I. 
  Terrain 
  

   Jurassique 
  ') 
  showed 
  the 
  presence 
  of 
  his 
  Middle 
  and 
  Upper 
  Oxfordian 
  

   beds, 
  the 
  former 
  consisting 
  of 
  sands 
  and 
  calcareous 
  grits 
  with 
  Am. 
  

   perarmatus 
  and 
  Am. 
  cordatus, 
  the 
  latter 
  of 
  marly 
  beds 
  with 
  Trigonia 
  

   perlata 
  (T. 
  clavellata), 
  Pholadomya 
  decemcostata, 
  Perna 
  mytiloides, 
  

   and 
  Oervillia 
  aviculoides. 
  Higher 
  in 
  the 
  series 
  are 
  pisolitic 
  beds 
  

   with 
  Nerincea, 
  and 
  Diceras-beds 
  with 
  Cardium 
  corallbium 
  and 
  Corbis 
  

   gigantea, 
  followed 
  by 
  marls 
  and 
  marly 
  limestones 
  of 
  Kimmeridgian 
  

   age 
  with 
  Ostrea 
  deltoidea, 
  Trigonia 
  Meriani 
  (" 
  muricata 
  "), 
  BhyncJio- 
  

   nella 
  inconstans, 
  &c. 
  

  

  Normandy. 
  — 
  This 
  district 
  should 
  be 
  studied 
  on 
  the 
  coast 
  ; 
  the 
  

   sections 
  there 
  are 
  complete, 
  and 
  afford 
  the 
  key 
  to 
  the 
  interior. 
  

   Caumont* 
  in 
  1825-8, 
  Hebertf 
  in 
  1860, 
  DollfusJ 
  in 
  1863, 
  and 
  

   Lennier§ 
  in 
  1870, 
  have 
  all 
  described 
  the 
  several 
  groups 
  of 
  rocks. 
  

   Each 
  of 
  the 
  above 
  authors 
  has 
  divided 
  or 
  read 
  them 
  in 
  their 
  own 
  

   way, 
  and 
  they 
  give 
  the 
  following 
  subdivisions 
  founded 
  on 
  the 
  sections 
  

   examined 
  by 
  them 
  : 
  — 
  

  

  Caumont. 
  Hebert. 
  Dollfus. 
  

  

  1. 
  Kimme 
  ridge 
  Clay. 
  1. 
  Coral 
  Rag. 
  1. 
  Ammonite-clays. 
  ^ 
  

  

  2. 
  Grlos 
  Sand 
  and 
  2. 
  Upper 
  Oxfordian. 
  2. 
  Pteroceras-marls. 
  | 
  y. 
  jr- 
  

   Blangy 
  Limestone. 
  )■ 
  --, 
  1U 
  ^" 
  

  

  3. 
  Coral 
  Rag. 
  3. 
  Middle 
  Oxfordain. 
  3. 
  Trigonia 
  - 
  clays 
  | 
  mencl 
  g 
  iau 
  - 
  

  

  4. 
  Oxford 
  Clay. 
  and 
  limestones. 
  J 
  

  

  * 
  ' 
  Explication 
  de 
  la 
  Carte 
  Geologique 
  de 
  Normandie,' 
  1825-8. 
  

   t 
  " 
  Du 
  Terrain 
  Jurassique 
  superieur 
  sur 
  les 
  cotes 
  de 
  la 
  Manche," 
  Bull. 
  Soc. 
  

   Geol. 
  France, 
  ser. 
  2, 
  vol. 
  xvii. 
  p.* 
  300. 
  

  

  I 
  ' 
  La 
  Faune 
  Kimmeridienne 
  du 
  cap 
  de 
  la 
  Heve.' 
  

  

  § 
  ' 
  Etudes 
  Geologiques 
  et 
  Paleontologiques 
  de 
  la 
  Haute 
  Normandie.' 
  

  

  