﻿F. 
  G. 
  H. 
  PRICE 
  ON 
  THE 
  GAULT 
  OF 
  FOLKESTONE. 
  357 
  

  

  depressed. 
  Aperture 
  oblique, 
  ovate, 
  the 
  length 
  being 
  nearly 
  double 
  

   the 
  width. 
  Inner 
  and 
  outer 
  lips 
  nearly 
  parallel. 
  Outer 
  lip 
  thin 
  ; 
  

   the 
  inner 
  lip, 
  which 
  is 
  somewhat 
  reflected 
  over 
  the 
  umbilicus, 
  

   is 
  callous 
  and 
  broader 
  at 
  its 
  upper 
  part, 
  where 
  it 
  forms 
  an 
  angle 
  at 
  

   the 
  point 
  where 
  it 
  joins 
  the 
  body-whorl. 
  

   Umbilicus 
  shallow 
  and 
  open. 
  

  

  millims. 
  

  

  Length 
  of 
  shell 
  12 
  

  

  Breadth 
  of 
  shell 
  10 
  

  

  Length 
  of 
  aperture 
  9 
  

  

  Breadth 
  of 
  aperture 
  4^ 
  

  

  This 
  shell 
  has 
  only 
  been 
  met 
  with 
  in 
  bed 
  IV. 
  of 
  the 
  Lower 
  

   Gault, 
  Folkestone. 
  

  

  A 
  large 
  Nucula 
  occurs 
  in 
  the 
  Gault 
  of 
  bed 
  II., 
  which 
  is 
  not 
  met 
  

   with 
  elsewhere 
  ; 
  this 
  I 
  have 
  always 
  considered 
  to 
  be 
  a 
  new 
  and 
  un- 
  

   described 
  species, 
  since 
  I 
  carefully 
  examined 
  the 
  figure 
  and 
  descrip- 
  

   tion 
  given 
  by 
  D'Orbigny 
  of 
  Nucula 
  ovata 
  in 
  the 
  Pal. 
  Prang. 
  Cret. 
  

   torn. 
  iii. 
  p. 
  173, 
  purporting 
  to 
  be 
  Hantell's 
  species. 
  I 
  then 
  found 
  

   that 
  he 
  has 
  mistaken 
  the 
  large 
  species, 
  which 
  is 
  peculiar 
  to 
  bed 
  II. 
  

   at 
  Folkestone, 
  for 
  what 
  has 
  always 
  been 
  taken 
  as 
  the 
  typical 
  form 
  

   of 
  Nucula 
  ovata, 
  Mantell, 
  which 
  has 
  a 
  range 
  throughout 
  the 
  Lower 
  

   Gault. 
  

  

  These 
  two 
  separate 
  species 
  are 
  constant 
  in 
  form, 
  and 
  differ 
  as 
  much 
  

   the 
  one 
  from 
  the 
  other 
  as 
  it 
  is 
  possible 
  for 
  two 
  Nuculce 
  to 
  do. 
  If 
  

   this 
  large 
  form, 
  which 
  is 
  figured 
  by 
  D'Orbigny, 
  be 
  taken 
  as 
  the 
  Nucula 
  

   ovata 
  of 
  Mantell, 
  then 
  that 
  which 
  has 
  hitherto 
  been 
  considered 
  

   Nucula 
  ovata 
  by 
  all 
  English 
  palaeontologists, 
  and 
  which 
  is 
  found 
  

   throughout 
  the 
  Gault 
  of 
  the 
  south-east 
  of 
  England, 
  and 
  does 
  not 
  

   appear 
  to 
  occur 
  at 
  all 
  in 
  France 
  (that 
  is 
  to 
  say, 
  it 
  has 
  not 
  been 
  

   described 
  by 
  D'Orbigny), 
  is 
  a 
  separate 
  and 
  distinct 
  species. 
  But 
  

   this 
  latter 
  fossil 
  is 
  the 
  typical 
  English 
  Gault 
  form 
  of 
  Nucula 
  

   ovata, 
  and 
  was 
  named, 
  described, 
  and 
  badly 
  figured 
  by 
  Dr. 
  Mantell 
  

  

  Natica 
  gaultina, 
  D'Orb. 
  Pal. 
  Franc;. 
  Cret. 
  t. 
  ii. 
  p. 
  156, 
  pi. 
  173. 
  figs. 
  3 
  &4. 
  

  

  = 
  Ampullaria 
  canaliculata, 
  Mantell, 
  1822, 
  Geol. 
  of 
  Sussex, 
  pi. 
  19. 
  fig. 
  13, 
  

   p. 
  87. 
  

  

  = 
  Natica 
  canaliculata, 
  Fitton, 
  1836, 
  Tr. 
  Geol. 
  Soc. 
  ser. 
  2, 
  vol. 
  iv. 
  pi. 
  11. 
  fig. 
  12. 
  

  

  The 
  above 
  two 
  species 
  are 
  common 
  in 
  the 
  Gault 
  of 
  England. 
  Natica 
  Clemen- 
  

   tina 
  is 
  met 
  with 
  in 
  beds 
  VI. 
  and 
  VII. 
  of 
  the 
  Lower 
  Gault 
  ; 
  whereas 
  N. 
  gaul- 
  

   tina 
  has 
  a 
  wider 
  range, 
  being 
  first 
  found 
  in 
  the 
  zone 
  of 
  Ammonites 
  interrwptus 
  

   at 
  the 
  base 
  of 
  the 
  Gault, 
  and 
  passing 
  all 
  through 
  the 
  various 
  beds 
  up 
  to 
  the 
  top. 
  

  

  There 
  are 
  four 
  other 
  species 
  obtained 
  from 
  the 
  Gault 
  of 
  France, 
  which 
  have 
  

   not 
  been 
  recorded 
  as 
  occurring 
  in 
  the 
  English 
  Gault. 
  They 
  are 
  : 
  — 
  

  

  Natica 
  Dupinii, 
  Leymerie, 
  1842, 
  Mem. 
  de 
  la 
  Soc. 
  Geol. 
  t. 
  v. 
  p. 
  13, 
  pi. 
  16. 
  

  

  fig. 
  7. 
  

   Natica 
  excavata, 
  Michelin, 
  1836, 
  Mem. 
  de 
  la 
  Soc. 
  Geol. 
  t. 
  iii. 
  pi. 
  12. 
  fig. 
  4. 
  

   Natica 
  ebvyna, 
  D'Orbigny, 
  Pal. 
  Franc. 
  Cret. 
  t. 
  ii. 
  p. 
  159, 
  pi. 
  173. 
  fig. 
  7. 
  

  

  Natica 
  Eauliniana, 
  D'Orbigny, 
  Pal. 
  Franc. 
  Cret, 
  t, 
  ii. 
  p. 
  160, 
  pi. 
  174. 
  fig. 
  1. 
  

   Q. 
  J. 
  G. 
  S. 
  No. 
  119. 
  2 
  c 
  

  

  