﻿484 
  PK0F. 
  J. 
  W. 
  JUDD 
  ON 
  THE 
  EOCENE 
  AND 
  OLIOOCENE 
  

  

  while 
  I 
  have 
  compared 
  the 
  whole 
  of 
  the 
  Headon 
  marine 
  forms 
  with 
  

   those 
  of 
  Colwell 
  Bay. 
  Nearly 
  100 
  species 
  are 
  known 
  and 
  have 
  

   been 
  recorded 
  by 
  competent 
  authorities 
  from 
  both 
  of 
  these 
  localities. 
  

  

  I, 
  on 
  the 
  contrary, 
  find 
  that 
  the 
  same 
  genus 
  is 
  constantly 
  repre- 
  

   sented 
  by 
  the 
  different 
  species 
  at 
  the 
  two 
  horizons, 
  and, 
  like 
  Yon 
  

   Konen, 
  I 
  recognize 
  a 
  considerable 
  proportion 
  of 
  the 
  Colw 
  ell-Bay 
  forms 
  

   as 
  identical 
  with 
  those 
  of 
  the 
  Brockenhnrst 
  series. 
  

  

  At 
  the 
  same 
  time, 
  as 
  both 
  Yon 
  Konen 
  and 
  I 
  have 
  admitted, 
  

   the 
  Colwell-Bay 
  beds 
  exhibit 
  much 
  more 
  estuarine 
  characters 
  than 
  

   do 
  the 
  strata 
  at 
  the 
  New 
  Forest 
  localities. 
  At 
  Lyndhurst 
  and 
  

   Brockenhurst 
  the 
  beds 
  appear 
  to 
  be 
  truly 
  marine, 
  containing, 
  as 
  Dr. 
  

   Duncan 
  has 
  shown, 
  reef-forming 
  corals 
  ; 
  but 
  at 
  Roydon 
  there 
  occur 
  

   a 
  few 
  specimens 
  of 
  Cyrena 
  and 
  Melania, 
  which 
  may 
  have 
  been 
  

   washed 
  in 
  from 
  a 
  neighbouring 
  river, 
  while 
  some 
  of 
  the 
  most 
  cha- 
  

   racteristically 
  marine 
  forms 
  are 
  absent 
  or 
  rare. 
  At 
  Colwell 
  Bay, 
  

   however, 
  the 
  admixture 
  of 
  freshwater 
  with 
  marine 
  Mollusca 
  becomes 
  

   much 
  more 
  marked 
  ; 
  many 
  of 
  the 
  marine 
  shells 
  are 
  dwarfed, 
  while 
  

   the 
  corals 
  and 
  such 
  genera 
  of 
  marine 
  Mollusca 
  as 
  could 
  not 
  tolerate 
  

   any 
  admixture 
  of 
  fresh 
  water 
  are 
  altogether 
  absent. 
  Further, 
  as 
  I 
  

   have 
  shown, 
  the 
  mass 
  of 
  brackish-water 
  strata 
  passes 
  within 
  a 
  very 
  

   short 
  distance 
  into 
  a 
  great 
  oyster-bank 
  ; 
  and 
  this, 
  when 
  traced 
  west- 
  

   ward, 
  is 
  replaced 
  by 
  a 
  number 
  of 
  thin 
  brackish-water 
  beds 
  which 
  

   at 
  Totland-Bay 
  brickyard 
  appear 
  on 
  the 
  point 
  of 
  thinning 
  out 
  and 
  

   disappearing 
  altogether*. 
  

  

  If 
  the 
  interpretation 
  which 
  I 
  have 
  advocated 
  requires 
  us 
  to 
  

   believe 
  that 
  the 
  Brockenhurst 
  beds, 
  which 
  at 
  Colwell 
  Bay 
  begin 
  to 
  

   exhibit 
  markedly 
  estuarine 
  characters, 
  have, 
  within 
  less 
  than 
  two 
  

   miles, 
  thinned 
  out 
  altogether 
  or 
  passed 
  into 
  freshwater 
  deposits, 
  the 
  

   theory 
  opposed 
  to 
  it 
  labours 
  under 
  still 
  greater 
  difficulties 
  ; 
  for 
  we 
  

   are 
  called 
  upon 
  by 
  it 
  to 
  believe 
  that 
  the 
  thick 
  masses 
  of 
  the 
  Headon- 
  

   Hill 
  limestones 
  have 
  almost 
  entirely 
  thinned 
  out 
  and 
  disappeared 
  

   at 
  Colwell 
  Bay. 
  The 
  Brockenhurst 
  beds 
  are 
  said 
  to 
  form 
  the 
  base 
  

   of 
  the 
  "' 
  Middle 
  Headon 
  ;" 
  and 
  of 
  this 
  Middle 
  Headon 
  there 
  are 
  said 
  

   to 
  be 
  clear 
  sections 
  at 
  Headon 
  Hill, 
  Colwell 
  Bay, 
  and 
  Hordwell. 
  

   Has 
  any 
  one 
  ever 
  detected 
  at 
  any 
  one 
  of 
  these 
  localities 
  a 
  bed 
  that 
  

   can 
  be 
  regarded 
  as 
  this 
  Brockenhurst 
  bed 
  ? 
  The 
  whole 
  of 
  the 
  

   Headon 
  beds, 
  both 
  sands 
  and 
  clays, 
  abound 
  with 
  Cerithiiim 
  con- 
  

   cavum 
  and 
  its 
  varieties. 
  Cerithia 
  occur 
  in 
  considerable 
  abundance 
  

   in 
  the 
  Brockenhurst 
  beds 
  : 
  but 
  Cerithium 
  concavum 
  is 
  absent 
  from 
  

  

  * 
  I 
  have 
  stated, 
  in 
  my 
  paper 
  and 
  section, 
  that 
  the 
  places 
  where 
  the 
  Colwell- 
  

   Bay 
  marine 
  bed, 
  if 
  it 
  be 
  continuous, 
  should 
  occur 
  in 
  Headon 
  Hill 
  are 
  concealed 
  

   by 
  gravel 
  and 
  landslips. 
  My 
  critics 
  declare 
  that 
  at 
  one 
  particular 
  point 
  there 
  

   is 
  no 
  gravel, 
  and 
  take 
  great 
  exception 
  to 
  my 
  description. 
  They 
  state 
  that 
  only 
  

   " 
  local 
  taluses" 
  occur. 
  I 
  can 
  only 
  ask 
  any 
  one 
  who 
  has 
  taken 
  the 
  footpath 
  from 
  

   the 
  keeper's 
  lodge 
  to 
  Headon 
  Cottage, 
  to 
  judge 
  if 
  my 
  statement 
  is 
  not 
  strictly 
  

   correct. 
  The 
  thinness 
  and 
  inconstancy 
  of 
  the 
  brackish-water 
  bed 
  at 
  Totland 
  

   Bay 
  brickyard 
  points 
  to 
  the 
  conclusion 
  that 
  it 
  is 
  on 
  the 
  point 
  of 
  dying 
  out 
  

   altogether. 
  Mr. 
  Gardner 
  has 
  obligingly 
  furnished 
  me 
  with 
  some 
  sections 
  he 
  

   had 
  made 
  by 
  digging 
  at 
  the 
  east 
  end 
  of 
  Headon 
  Hill, 
  which 
  seem 
  to 
  show 
  that 
  

   the 
  Brockenhurst 
  marine 
  band 
  has 
  entirely 
  disappeared. 
  But, 
  as 
  Mr. 
  Prest- 
  

   wich's 
  section 
  long 
  ago 
  showed, 
  traces 
  of 
  brackish-water 
  beds 
  are 
  found 
  on 
  this 
  

   horizon 
  at 
  the 
  other 
  end 
  of 
  the 
  hill. 
  

  

  