﻿Quart. 
  Journ.Geol.Soc. 
  Vol. 
  LIII.P1.XXVIII 
  

  

  , 
  A 
  ..^w 
  i 
  

  

  L 
  

  

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  X 
  

  

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  >^ 
  

  

  :i 
  

  

  v 
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  I 
  

  

  16 
  

  

  19 
  

  

  xj 
  

  

  17 
  

  

  X2/2 
  

  

  IS 
  

  

  CHALK 
  ROCK 
  MOLLUSCA. 
  

  

  Edwin 
  Wilson, 
  Cambridge 
  

  

  