﻿352 
  F. 
  G. 
  H. 
  PRICE 
  ON 
  THE 
  GATJLT 
  OF 
  FOLKESTONE. 
  

  

  nodules 
  below, 
  and 
  passes 
  up 
  into 
  bed 
  X, 
  where, 
  however, 
  it 
  is 
  not 
  

   frequently 
  found. 
  I 
  would 
  suggest 
  that 
  bed 
  IX. 
  be 
  considered 
  the 
  

   zone 
  of 
  Ammonites 
  varicosus. 
  

  

  The 
  geologist 
  will 
  at 
  all 
  times 
  when 
  working 
  in 
  the 
  Gault 
  readily 
  

   be 
  able 
  to 
  fix 
  his 
  position, 
  and 
  know 
  that 
  when 
  he 
  discovers 
  these 
  

   two 
  most 
  characteristic 
  fossils 
  he 
  is 
  upon 
  the 
  base 
  of 
  the 
  Upper 
  

   Gault. 
  

  

  A 
  variety 
  of 
  Ammonites 
  lautus 
  occurs 
  in 
  this 
  zone, 
  ranging 
  from 
  

   the 
  nodule-bed, 
  where 
  it 
  is 
  found 
  in 
  the 
  form 
  of 
  casts, 
  up 
  to 
  a 
  

   hard 
  seam 
  near 
  the 
  top, 
  but 
  never 
  having 
  been 
  noted 
  as 
  passing 
  

   above 
  that 
  horizon. 
  This 
  Ammonite 
  belonging 
  to 
  the 
  group 
  Dentati, 
  

   forms 
  another 
  exception 
  to 
  the 
  rule 
  of 
  the 
  Upper 
  Gault 
  being 
  re- 
  

   stricted 
  exclusively 
  to 
  Ammonites 
  of 
  the 
  group 
  Cristati. 
  

  

  Just 
  below 
  the 
  hard 
  seam 
  at 
  the 
  top 
  of 
  this 
  zone, 
  Ammonites 
  ros- 
  

   tratus, 
  Sow. 
  = 
  Ammonites 
  inflatus 
  of 
  D'Orbigny, 
  makes 
  its 
  first 
  

   appearance. 
  It 
  extends 
  thence 
  up 
  to 
  the 
  top 
  of 
  the 
  Gault. 
  

  

  Pholadomya 
  fabrina, 
  D'Orb., 
  is 
  only 
  met 
  with 
  in 
  situ 
  in 
  this 
  bed; 
  

   it 
  certainly 
  is 
  found 
  in 
  the 
  nodule-bed 
  No. 
  VIII., 
  but 
  then 
  only 
  in 
  

   the 
  form 
  of 
  rolled 
  casts. 
  No 
  other 
  fossils, 
  so 
  far 
  as 
  I 
  have 
  as 
  yet 
  

   been 
  able 
  to 
  ascertain, 
  can 
  be 
  considered 
  to 
  be 
  peculiar 
  to 
  this 
  zone 
  ; 
  

   but 
  the 
  two 
  following 
  well-known 
  Upper-Gault 
  forms 
  make 
  their 
  

   first 
  appearance 
  in 
  it 
  : 
  — 
  

  

  Pleurotomaria 
  Gribbsii, 
  Sow. 
  M.C. 
  Scaphites 
  sequalis, 
  Sow. 
  

  

  Bed^. 
  

  

  Commences 
  at 
  the 
  crushed 
  band 
  of 
  Inoceramus 
  sulcatus, 
  and 
  ex- 
  

   tends 
  upwards 
  to 
  a 
  line 
  of 
  phosphatic 
  nodules 
  containing 
  specimens 
  of 
  

   Pecten 
  Raulinianus, 
  D'Orb., 
  5 
  feet 
  1 
  inch 
  above 
  the 
  top 
  of 
  bed 
  IX. 
  

  

  The 
  Gault 
  of 
  this 
  zone 
  is 
  homogeneous, 
  hard, 
  and 
  of 
  a 
  pale 
  cold 
  

   grey 
  colour, 
  poor 
  in 
  organic 
  remains, 
  and 
  partakes 
  more 
  of 
  the 
  

   character 
  of 
  marl 
  than 
  clay, 
  as 
  does 
  the 
  whole 
  of 
  the 
  Gault 
  of 
  the 
  

   upper 
  division, 
  which 
  contains 
  as 
  much 
  as 
  26 
  per 
  cent, 
  of 
  carbonate 
  

   of 
  lime 
  — 
  a 
  fact 
  sufficient 
  of 
  itself 
  to 
  account 
  for 
  the 
  shells 
  of 
  the 
  

   fossils 
  being 
  so 
  seldom 
  preserved. 
  

  

  At 
  a 
  distance 
  of 
  2 
  feet 
  8 
  inches 
  above 
  bed 
  IX. 
  a 
  line 
  of 
  phos- 
  

   phatic 
  nodules 
  is 
  met 
  with, 
  in 
  which 
  Plicatula 
  jpectinoides 
  occurs 
  in 
  

   good 
  condition 
  and 
  in 
  large 
  quantities. 
  

  

  At 
  the 
  base 
  of 
  this 
  bed 
  Rosiellaria 
  maxima 
  *, 
  the 
  largest 
  known 
  

   Rostellaria 
  from 
  the 
  Gault, 
  was 
  procured. 
  

  

  Between 
  the 
  last-mentioned 
  seam 
  of 
  phosphatic 
  nodules 
  and 
  the 
  

   line 
  of 
  nodules 
  containing 
  Pecten 
  Raulinianus, 
  forming 
  the 
  base 
  of 
  

   bed 
  XI., 
  the 
  clay, 
  which 
  has 
  a 
  thickness 
  of 
  2 
  feet 
  5 
  inches, 
  is 
  much 
  

   mottled. 
  Pentacrinus 
  Fittoni 
  occurs 
  in 
  masses, 
  whereas 
  in 
  all 
  

   other 
  parts 
  of 
  the 
  Gault 
  it 
  is 
  only 
  found 
  in 
  fragments. 
  Cidaris 
  

   gaultina 
  is 
  only 
  met 
  with 
  between 
  these 
  two 
  lines 
  of 
  nodules. 
  

  

  Many 
  pieces 
  of 
  bones 
  of 
  Chelonians 
  and 
  fishes 
  are 
  obtained 
  from 
  

   the 
  same 
  horizon. 
  

  

  Upon 
  two 
  separate 
  occasions 
  Griffiths 
  has 
  discovered 
  in 
  this 
  zone, 
  

   * 
  See 
  Geol. 
  Mag. 
  March 
  1873, 
  vol. 
  x. 
  pi. 
  vi. 
  

  

  