﻿404 
  "VV. 
  WHITAKER 
  ON 
  THE 
  OCCURRENCE 
  OF 
  

  

  all 
  the 
  fossils 
  were 
  in 
  the 
  state 
  of 
  casts 
  and 
  impressions 
  in 
  one 
  of 
  

   the 
  layers 
  of 
  ironstone, 
  which 
  yielded 
  the 
  following 
  : 
  — 
  

  

  Nassa 
  elongata. 
  Mya 
  arenaria. 
  

  

  Natica 
  occlusa. 
  Mytilus 
  edulis. 
  

  

  Trophon 
  antiquus 
  (lower 
  whorls). 
  Pecten 
  opercularis. 
  

  

  Cardium 
  Parkinsoni. 
  Tellina. 
  

  

  Mactra. 
  Pollicipes. 
  

  

  Modiola 
  modiolus. 
  Balanophyllia. 
  

  

  From 
  their 
  unsatisfactory 
  state 
  these 
  fossils 
  are 
  of 
  little 
  value 
  in 
  

   deciding 
  the 
  age 
  of 
  the 
  bed 
  ; 
  indeed 
  Mr. 
  Etheridge 
  assures 
  me 
  that 
  

   it 
  is 
  hard 
  in 
  most 
  cases 
  to 
  assign 
  the 
  specific 
  names 
  with 
  any 
  cer- 
  

   tainty, 
  and 
  consequently 
  it 
  is 
  open 
  to 
  suggest 
  that 
  the 
  bed 
  might 
  be 
  

   a 
  fossiliferous 
  member 
  of 
  the 
  Glacial 
  Drift. 
  The 
  reasons, 
  however, 
  

   for 
  referring 
  it 
  to 
  the 
  Crag 
  are 
  as 
  follows 
  : 
  — 
  

  

  1. 
  That 
  no 
  fossiliferous 
  Glacial 
  Drift 
  is 
  known 
  within 
  a 
  very 
  

   great 
  distance, 
  much 
  greater 
  than 
  the 
  distance 
  of 
  the 
  Crag 
  tract 
  (on 
  

   the 
  east). 
  

  

  2. 
  That 
  no 
  layer 
  of 
  phosphatie 
  nodules 
  is 
  known 
  to 
  occur 
  at 
  the 
  

   base 
  of 
  the 
  Drift, 
  whilst 
  the 
  presence 
  of 
  such 
  a 
  layer 
  at 
  the 
  base 
  of 
  

   the 
  Crag 
  is 
  very 
  usual. 
  

  

  3. 
  That 
  the 
  bed 
  is 
  unlike 
  the 
  well- 
  developed 
  Drift 
  of 
  the 
  neigh- 
  

   bourhood, 
  whilst 
  it 
  is 
  like 
  some 
  of 
  the 
  less 
  fossiliferous 
  beds 
  of 
  the 
  

   Red 
  Crag. 
  

  

  As 
  might 
  be 
  expected, 
  this 
  small 
  patch 
  belongs 
  to 
  the 
  upper 
  and 
  

   wider-spread 
  division, 
  the 
  Red 
  Crag 
  *, 
  and 
  not 
  to 
  the 
  lower 
  and 
  rarer 
  

   White 
  (or 
  Coralline) 
  Crag. 
  Its 
  chief 
  interest 
  consists 
  in 
  the 
  dist- 
  

   ance 
  from 
  any 
  yet 
  known 
  masses, 
  it 
  being 
  some 
  miles 
  westward 
  of 
  

   all 
  other 
  exposures. 
  Perhaps 
  Crag 
  may 
  yet 
  be 
  found 
  still 
  further 
  

   westward 
  ; 
  for 
  my 
  colleague 
  Mr. 
  Penning 
  showed 
  me 
  a 
  section 
  near 
  

   Stoke 
  (west 
  of 
  Clare) 
  where, 
  between 
  a 
  mass 
  of 
  Drift 
  sand 
  and 
  the 
  

   Chalk, 
  was 
  a 
  bed 
  of 
  angular 
  flints 
  and 
  flint-pebbles, 
  in 
  which 
  I 
  

   found 
  one 
  very 
  small 
  piece 
  of 
  phosphatized 
  bone, 
  and 
  on 
  the 
  top 
  of 
  

   wbich 
  we 
  were 
  told 
  a 
  mass 
  of 
  shells 
  had 
  once 
  been 
  found. 
  We 
  

   have 
  since 
  seen 
  some 
  of 
  these, 
  which 
  turn 
  out 
  to 
  be 
  Purpura 
  lapillus, 
  

   the 
  common 
  Sudbury 
  shell. 
  

  

  The 
  level 
  of 
  the 
  Crag 
  is, 
  I 
  believe, 
  far 
  higher 
  at 
  Sudbury 
  than 
  in 
  

   any 
  other 
  part 
  of 
  the 
  Eastern 
  Counties. 
  I 
  fear 
  that 
  the 
  layer 
  of 
  

   phosphatie 
  nodules 
  at 
  the 
  bottom 
  is 
  here 
  too 
  thin, 
  too 
  irregular, 
  and 
  

   too 
  much 
  mixed 
  with 
  flint-pebbles 
  to 
  be 
  of 
  economical 
  value. 
  

  

  P.S. 
  — 
  Since 
  the 
  above 
  was 
  written 
  Mr. 
  Penning 
  and 
  myself 
  have 
  

   found 
  traces 
  of 
  the 
  bottom 
  bed 
  of 
  the 
  Crag 
  southwards 
  of 
  Thaxted, 
  in 
  

   Essex, 
  in 
  the 
  shape 
  of 
  a 
  few 
  small 
  phosphatie 
  nodules 
  and 
  a 
  piece 
  of 
  

   phosphatized 
  bone 
  in 
  a 
  very 
  thin 
  layer 
  of 
  gravel 
  at 
  the 
  bottom 
  of 
  

   Drift 
  sand 
  and 
  lying 
  on 
  London 
  Clay. 
  [April 
  1874.] 
  

  

  A 
  few 
  days 
  after 
  this 
  paper 
  was 
  read 
  [June], 
  when 
  with 
  my 
  

   colleague 
  Mr. 
  Bennett, 
  I 
  found 
  Thanet 
  Sand 
  a 
  little 
  north 
  of 
  Had- 
  

   leigh, 
  and 
  south 
  of 
  that 
  town 
  some 
  nodules 
  of 
  ironstone 
  in 
  sand 
  

   (resting 
  on 
  London 
  Clay), 
  which 
  were 
  crowded 
  with 
  casts 
  of 
  shells, 
  

  

  * 
  Mr. 
  S. 
  V. 
  Wood, 
  Jun., 
  thinks 
  it 
  most 
  likely 
  to 
  belong 
  to 
  the 
  higher 
  part 
  

   (Chillesford 
  beds) 
  of 
  this 
  division. 
  

  

  