﻿F. 
  O. 
  H. 
  TRICE 
  ON 
  THE 
  GATTLT 
  OF 
  FOLKESTONE. 
  347 
  

  

  per 
  cent. 
  

  

  Water 
  and 
  organic 
  matter 
  8-25 
  

  

  Carbonate 
  of 
  lime 
  8-61 
  

  

  Silica, 
  silicates, 
  oxides 
  of 
  iron*, 
  pyrites 
  &c 
  81*93 
  

  

  Not 
  f 
  Chloride 
  of 
  sodium 
  (consid.) 
  ] 
  

   actually 
  J 
  Carbonate 
  of 
  magnesia 
  (traces) 
  I 
  ,~i 
  

  

  estima- 
  j 
  Sulphuric 
  acid 
  f 
  

  

  ted 
  [ 
  Phosphoric 
  acid 
  (traces) 
  J 
  

  

  100-00 
  

   " 
  This 
  differs 
  principally 
  from 
  the 
  upper 
  bed 
  in 
  containing 
  less 
  

   carbonate 
  of 
  lime, 
  and 
  less 
  phosphoric 
  acid, 
  but 
  much 
  more 
  iron 
  and 
  

   more 
  organic 
  matter." 
  

  

  Bed 
  III. 
  

  

  Known 
  as 
  the 
  " 
  light 
  bed," 
  or 
  " 
  crab-bed," 
  from 
  the 
  fact 
  of 
  many 
  

   of 
  the 
  Crustaceans 
  found 
  in 
  the 
  Gault 
  being 
  derived 
  from 
  it. 
  

  

  It 
  may 
  be 
  readily 
  recognized 
  from 
  any 
  other 
  by 
  its 
  light 
  fawn- 
  

   coloured 
  clay, 
  which 
  exhibits 
  a 
  striking 
  contrast 
  to 
  the 
  very 
  dark 
  co- 
  

   lour 
  of 
  the 
  bed 
  last 
  described. 
  

  

  Its 
  thickness 
  is 
  4 
  feet 
  6 
  inches, 
  being 
  measured 
  from 
  the 
  top 
  of 
  bed 
  

   II. 
  to 
  a 
  line 
  of 
  nodules 
  containing 
  many 
  rolled 
  fossils 
  with 
  the 
  shell 
  

   preserved 
  on 
  them, 
  carapaces 
  of 
  Palceocorystes 
  Stolcesii 
  and 
  P. 
  Bro- 
  

   deripii, 
  Hamites 
  and 
  bones 
  of 
  saurians 
  and 
  fishes. 
  

  

  A 
  remarkably 
  fine 
  type 
  of 
  Inoceramus 
  concentricus 
  occurs 
  in 
  this 
  

   line 
  of 
  nodules. 
  

  

  Tabular 
  masses 
  of 
  ironstone 
  occur 
  in 
  various 
  parts 
  of 
  this 
  bed, 
  

   being 
  of 
  the 
  same 
  light 
  fawn-colour 
  as 
  the 
  clay. 
  Similar 
  ironstone 
  

   also 
  occurs 
  in 
  bed 
  V. 
  It 
  contains 
  many 
  of 
  the 
  fossils 
  common 
  to 
  the 
  

   bed, 
  Corbula 
  elegans 
  being 
  met 
  with 
  in 
  it 
  in 
  large 
  numbers. 
  

  

  For 
  the 
  following 
  analysis 
  of 
  this 
  ironstone 
  I 
  am 
  indebted 
  to 
  Mr. 
  

   W. 
  H. 
  Hudleston 
  :— 
  

  

  " 
  A 
  clay 
  ironstone 
  free 
  from 
  grit. 
  The 
  bulk 
  of 
  the 
  mass 
  consists 
  of 
  

   pulverulent 
  carbonate 
  of 
  lime, 
  ferrous 
  carbonate, 
  extremely 
  fine 
  par- 
  

   ticles 
  of 
  clay 
  &c. 
  with 
  about 
  2 
  per 
  cent 
  of 
  pyrites. 
  Dried 
  at 
  100 
  C. 
  : 
  — 
  

  

  Amount 
  of 
  metallic 
  iron 
  (principally 
  as 
  protoxide) 
  .... 
  29-40 
  

   Add 
  for 
  iron 
  in 
  combination 
  with 
  sulphur 
  (say) 
  1-00 
  

  

  Total 
  metallic 
  iron 
  30-40 
  " 
  

  

  Bed 
  IV. 
  

  

  This 
  is 
  a 
  narrow 
  band 
  which 
  was 
  apparently 
  overlooked 
  by 
  Mr. 
  

   De 
  Ranee, 
  or 
  not 
  considered 
  by 
  him 
  of 
  sufficient 
  importance 
  to 
  be 
  

   constituted 
  into 
  a 
  separate 
  bed. 
  It 
  is 
  measured 
  from 
  the 
  line 
  of 
  

   nodules 
  containing 
  the 
  carapaces 
  of 
  Crustaceans 
  before 
  named, 
  to 
  a 
  

   line 
  of 
  phosphatic 
  nodules 
  and 
  rolled 
  casts 
  of 
  fossils. 
  Imbedded 
  in 
  

   many 
  of 
  the 
  fragments 
  of 
  phosphate 
  a 
  very 
  small 
  species 
  of 
  Hoplo- 
  

   paria 
  is 
  met 
  with, 
  which 
  species 
  is 
  not 
  found 
  in 
  any 
  other 
  part 
  of 
  the 
  

   Gault. 
  

  

  * 
  Metallic 
  iron 
  425 
  per 
  cent. 
  

  

  