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  PUOCEEDINGS 
  OF 
  THE 
  JIALACOLOGICAL 
  SOCIEXr. 
  

  

  The 
  latest 
  and 
  most 
  exhaustive 
  researches 
  on 
  the 
  Britisli 
  Chalk 
  are 
  

   undoubtedly 
  those 
  made 
  by 
  Dr. 
  Arthur 
  W. 
  Uowe 
  ' 
  in 
  a 
  series 
  of 
  

   memoirs 
  on 
  "The 
  Zones 
  of 
  the 
  White 
  Chalk 
  of 
  the 
  English 
  Coast", 
  

   published 
  between 
  1900 
  and 
  1908, 
  the 
  maps 
  to 
  which 
  were 
  constructed 
  

   by 
  Mr. 
  C. 
  Davies 
  Sherborn. 
  From 
  long 
  and 
  careful 
  collecting, 
  the 
  

   author 
  plans 
  out 
  the 
  zonal 
  distribution 
  of 
  fossils 
  in 
  the 
  coastal 
  white 
  

   chalk 
  deposits 
  of 
  England, 
  as 
  observed 
  in 
  Kent, 
  Sussex, 
  the 
  Isle 
  of 
  

   Wight, 
  Dorset, 
  Devonshire, 
  and 
  Yorkshire. 
  

  

  He 
  divided 
  these 
  deposits 
  into 
  seven 
  zones, 
  but 
  the 
  only 
  mollusc 
  

   used 
  as 
  an 
  index-fossil 
  was 
  that 
  of 
  the 
  Cephalopod 
  Actinocamax 
  

   quadratus^ 
  Avhich 
  is 
  regarded 
  as 
  characterizing 
  the 
  latest 
  or 
  newest 
  

   zone 
  of 
  the 
  series, 
  the 
  remainder 
  being 
  Echinoderms 
  and 
  Brachiopods. 
  

   The 
  distribution 
  of 
  the 
  various 
  species 
  of 
  the 
  Mollusca 
  is, 
  however, 
  

   most 
  minutely 
  treated, 
  and 
  by 
  a 
  system 
  of 
  tables 
  the 
  zonal 
  position 
  of 
  

   mnj 
  form 
  can 
  be 
  immediately 
  ascertained, 
  this 
  same 
  remark 
  applying 
  

   to 
  the 
  other 
  members 
  of 
  the 
  invertebrate 
  groups 
  of 
  zoology. 
  

  

  The 
  arrangement 
  of 
  these 
  zones 
  and 
  their 
  characteristic 
  Mollusca 
  

   iire 
  given 
  as 
  follows 
  : 
  — 
  

  

  Senonian 
  (zone 
  of 
  Actinocamax 
  quadratus). 
  Cephalopoda 
  : 
  

   Actinocamax 
  quadratiis, 
  granulatus 
  {Merceyi)\ 
  JSamites 
  ; 
  Scapkites 
  

   inflatus. 
  Pelecypoda 
  : 
  Bioceramus 
  lingua; 
  Ostrea 
  Wegmanniana; 
  

   Avicula 
  temiicostata. 
  (Zone 
  of 
  Marstqyites 
  testudinarius.) 
  Cephalo- 
  

   poda 
  : 
  Actinocamax 
  granulatus, 
  verus 
  ; 
  Ammonites 
  leptophyllus. 
  

   Pelecypoda 
  : 
  Ostrea 
  vesicularis, 
  Wegmanniatia. 
  (Zone 
  of 
  3Iicraster 
  

   coranguinmn.) 
  Cephalopoda: 
  Actinocamax 
  granulatus, 
  ivestfalicus. 
  

   Pelecypoda 
  : 
  Inoceramus 
  Cmieri, 
  involiitus. 
  (Zone 
  of 
  Micrasfer 
  

   cortesttidinarium.) 
  Pelecypoda: 
  Plicatula 
  Barroisi 
  ; 
  Inoceramus 
  

   LamarcM. 
  

  

  TuKois^iAN 
  (zone 
  of 
  Holaster 
  planus). 
  Gastropoda 
  : 
  Pleurotomaria 
  

   perspectiva; 
  Turho 
  gcmmatus. 
  Pelecypoda; 
  Inoceramus 
  LamarcM, 
  

   Brovgniarti 
  ; 
  Plicatula 
  Barroisi; 
  Ostrea 
  prohoscidea. 
  (Zone 
  of 
  

   Terehratulina 
  gracilis.) 
  Cephalopoda 
  : 
  Ammonites 
  peramplus. 
  

   Pelecypoda 
  : 
  Inoceramus 
  labiatus, 
  Brongniarti, 
  Lamar 
  chi 
  ; 
  

   Sp>ondylus 
  spinosus 
  ; 
  Ostrea 
  vesicularis. 
  (Zone 
  of 
  Rhynchonella 
  

   Cuvieri.) 
  Cephalopoda: 
  Ammonites 
  Cunningtoni, 
  peramplus. 
  

   Pelecj'poda 
  : 
  Inoceramus 
  labiatus, 
  Lamarchi 
  ; 
  Ostrea 
  vesicularis. 
  

  

  In 
  concluding 
  my 
  resume 
  of 
  the 
  geological 
  zones 
  it 
  is 
  almost 
  needless 
  

   to 
  remark 
  that 
  due 
  attention 
  to 
  such 
  a 
  subject 
  is 
  a 
  necessary 
  adjunct 
  

   to 
  accuracy 
  of 
  collecting, 
  and 
  all 
  studies 
  in 
  this 
  direction 
  must 
  lead 
  to 
  

   satisfactory 
  results. 
  No 
  longer 
  is 
  the 
  palaeontologist 
  contented 
  with 
  

   acquiring 
  his 
  specimens 
  indiscriminately 
  from 
  a 
  quarry 
  or 
  a 
  section, 
  

   but 
  he 
  is 
  careful 
  to 
  obtain 
  them 
  from 
  each 
  separate 
  bed, 
  so 
  that 
  

   he 
  may 
  become 
  acquainted 
  with 
  individual 
  faunas, 
  the 
  organisms 
  

   of 
  which 
  will 
  often 
  present 
  interesting 
  points 
  of 
  variation 
  and 
  change. 
  

   and 
  so 
  form 
  the 
  basis 
  of 
  inquiries 
  connected 
  with 
  the 
  evolution 
  of 
  

   genera 
  and 
  species. 
  

  

  Proc. 
  Geol. 
  Assoc, 
  vol. 
  xvi, 
  pp. 
  289-368 
  (Kent 
  and 
  Sussex), 
  1900; 
  vol. 
  xvii, 
  

   pp. 
  1-76 
  (Dorset), 
  1901; 
  vol. 
  xviii, 
  pp. 
  1-51 
  (Devon), 
  1903; 
  vol. 
  xviii, 
  

   pp. 
  193-296 
  (Yoikshh-e), 
  1904 
  ; 
  vol. 
  xx, 
  pp. 
  209-352 
  (Isle 
  of 
  Wight), 
  1908. 
  

  

  