﻿348 
  F. 
  G. 
  H. 
  PRICE 
  ON 
  THE 
  GAULT 
  OF 
  FOLKESTONE. 
  

  

  The 
  total 
  thickness 
  of 
  this 
  bed 
  is 
  four 
  inches; 
  in 
  colour 
  it 
  is 
  slightly 
  

   darker 
  than 
  the 
  preceding 
  bed 
  No. 
  III. 
  and 
  not 
  mottled 
  like 
  the 
  clay 
  

   of 
  bed 
  No. 
  V. 
  

  

  Comparatively 
  few 
  fossils 
  are 
  met 
  with 
  in 
  this 
  bed 
  ; 
  the 
  following 
  

   may 
  be 
  regarded 
  as 
  peculiar 
  to 
  it 
  : 
  — 
  

  

  Ammonites 
  Delaruei, 
  D'Orb., 
  a 
  form 
  belonging 
  to 
  the 
  group 
  Cristati, 
  

   which 
  may 
  be 
  considered 
  characteristic 
  of 
  the 
  Upper 
  Gault 
  as 
  the 
  

   groups 
  Dentati 
  and 
  Tuberculati 
  are 
  of 
  the 
  Lower. 
  Ammonites 
  cor- 
  

   nutus, 
  Pictet, 
  and 
  Ammonites 
  Roissyanus, 
  D'Orb., 
  are 
  the 
  only 
  other 
  

   forms 
  belonging 
  to 
  the 
  group 
  Cristati 
  that 
  I 
  have 
  met 
  with 
  in 
  the 
  

   Lower 
  Gault 
  ; 
  and 
  as 
  only 
  these 
  three 
  forms 
  have 
  been 
  found 
  in 
  the 
  

   Lower 
  Gault, 
  the 
  Cristati 
  group 
  of 
  Ammonites 
  may 
  still 
  be 
  considered 
  

   characteristic 
  of 
  the 
  Upper 
  division. 
  

  

  An 
  Ammonite 
  possessed 
  of 
  very 
  long 
  spines 
  or 
  tubercles, 
  which 
  may 
  

   be 
  classed 
  as 
  a 
  variety 
  of 
  Ammonites 
  tuberculatus, 
  Sow., 
  M. 
  C. 
  ; 
  a 
  small 
  

   species 
  of 
  Natica, 
  which 
  will 
  be 
  subsequently 
  described 
  in 
  this 
  paper 
  

   as 
  Natiea 
  obliqua 
  ; 
  and 
  Fusus 
  gaultinus. 
  

  

  The 
  conditions 
  under 
  which 
  this 
  bed 
  was 
  formed 
  appear 
  to 
  have 
  been 
  

   especially 
  favourable 
  to 
  the 
  development 
  of 
  Dentalium 
  decussatum, 
  

   remarkably 
  fine 
  specimens 
  of 
  which 
  occur 
  between 
  these 
  lines 
  of 
  

   nodules. 
  

  

  I 
  submitted 
  one 
  of 
  the 
  nodules 
  from 
  the 
  last-described 
  band 
  (in 
  

   fact, 
  one 
  containing 
  a 
  specimen 
  of 
  the 
  small 
  Hoploparia) 
  to 
  my 
  friend 
  

   Mr. 
  Hudleston, 
  who 
  has 
  reported 
  to 
  me 
  the 
  following 
  results: 
  — 
  

  

  " 
  This 
  is 
  a 
  mixture 
  of 
  carbonate 
  of 
  lime 
  with 
  phosphate 
  of 
  lime 
  

   and 
  iron, 
  some 
  clay, 
  organic 
  matter, 
  and 
  pyrites. 
  

  

  "The 
  amount 
  of 
  phosphoric 
  anhydride 
  in 
  the 
  sample 
  dried 
  at 
  

   100 
  C. 
  is 
  

  

  25-53 
  per 
  cent 
  = 
  55*60 
  tricalcic 
  phosphate." 
  

  

  Bed 
  V. 
  

  

  This 
  bed 
  may 
  consistently 
  be 
  termed 
  the 
  " 
  coral 
  bed," 
  on 
  account 
  

   of 
  the 
  quantity 
  of 
  corals 
  which 
  it 
  contains. 
  

  

  Its 
  thickness 
  is 
  1 
  foot 
  6 
  inches. 
  The 
  clay 
  is 
  of 
  a 
  dark 
  colour, 
  

   spotted 
  to 
  within 
  a 
  few 
  inches 
  of 
  the 
  top 
  with 
  light 
  fawn-coloured 
  

   markings. 
  

  

  It 
  is 
  measured 
  from 
  the 
  line 
  of 
  nodules 
  containing 
  the 
  fossil 
  casts 
  

   up 
  to 
  a 
  line 
  where 
  the 
  clay 
  becomes 
  more 
  strongly 
  mottled. 
  

  

  This 
  bed 
  is 
  considered 
  by 
  Mr. 
  De 
  Eance 
  to 
  be 
  the 
  zone 
  of 
  Nautilus 
  

   Clementinus 
  ; 
  but 
  as 
  that 
  fossil 
  is 
  by 
  no 
  means 
  peculiar 
  to 
  it, 
  and 
  

   makes 
  its 
  first 
  appearance 
  in 
  bed 
  III., 
  and 
  has 
  been 
  met 
  with 
  in 
  every 
  

   bed 
  up 
  to 
  and 
  in 
  bed 
  XL, 
  I 
  do 
  no 
  not 
  think 
  we 
  can 
  specialize 
  it 
  as 
  

   the 
  zone 
  of 
  Nautilus 
  Clementinus, 
  but 
  rather 
  as 
  the 
  zone 
  of 
  Ammo- 
  

   nites 
  lautus, 
  as 
  the 
  typical 
  form 
  of 
  this 
  species 
  makes 
  its 
  first 
  appear- 
  

   ance 
  in 
  it. 
  

  

  The 
  following 
  fossils 
  appear 
  to 
  be 
  peculiar 
  to 
  this 
  bed 
  : 
  — 
  

  

  Astarte 
  Dupiniana, 
  D' 
  Orb. 
  Turritella, 
  two 
  sp. 
  undetermined. 
  

   Cerithium 
  Dupinianum, 
  D'Orb. 
  Solarium 
  albense, 
  D'Orb. 
  

   subspinosum? 
  Desk. 
  moniliferum, 
  Mich. 
  

  

  