﻿STRATA 
  OE 
  THE 
  HAMPSHIRE 
  BASEST. 
  485 
  

  

  these 
  beds 
  at 
  all 
  the 
  typical 
  localities*. 
  Quite 
  apart 
  from 
  the 
  

   evidence 
  afforded 
  by 
  the 
  equivalent 
  strata 
  of 
  the 
  Continent 
  as 
  to 
  

   the 
  relative 
  positions 
  of 
  the 
  beds 
  which 
  contain 
  the 
  Brockenhurst 
  

   fauna 
  and 
  those 
  belonging 
  to 
  the 
  zone 
  of 
  Cerithium 
  concavum, 
  it 
  

   seems 
  to 
  me 
  that 
  the 
  theory 
  of 
  Messrs. 
  Keeping 
  and 
  Tawney 
  labours 
  

   under 
  insuperable 
  difficulties. 
  

  

  If 
  the 
  Colwell-Bay 
  estuarine 
  strata 
  be 
  not 
  the 
  nuvio-niarine 
  

   representatives 
  of 
  the 
  Brockenhurst 
  series, 
  then 
  it 
  must 
  be 
  main- 
  

   tained 
  that 
  the 
  last-mentioned 
  series, 
  which 
  is 
  so 
  well 
  represented 
  

   both 
  at 
  Whitecliff 
  Bay 
  and 
  in 
  the 
  xTew 
  Forest, 
  has 
  altogether 
  

   thinned 
  out 
  and 
  disappeared 
  from 
  the 
  sections 
  of 
  the 
  west 
  end 
  of 
  

   the 
  Isle 
  of 
  Wight, 
  or 
  that 
  the 
  marine 
  beds 
  are 
  represented 
  by 
  

   others 
  of 
  purely 
  freshwater 
  character. 
  This 
  appears 
  to 
  be 
  the 
  view 
  

   adopted 
  by 
  Messrs. 
  Keeping 
  and 
  Tawney. 
  I 
  believe, 
  however, 
  that 
  

   the 
  interpretation 
  which 
  I 
  have 
  given 
  is 
  the 
  one 
  which 
  best 
  accords 
  

   with 
  the 
  facts 
  of 
  the 
  case 
  ; 
  and 
  it 
  has 
  the 
  additional 
  merit 
  of 
  bringing 
  

   our 
  own 
  series 
  of 
  strata 
  into 
  perfect 
  harmony 
  with 
  the 
  succession 
  

   made 
  out 
  by 
  the 
  labours 
  of 
  continental 
  observers 
  with 
  respect 
  to 
  the 
  

   equivalent 
  deposits 
  in 
  France, 
  Belgium, 
  and 
  Northern 
  German}*. 
  

  

  IT. 
  Conclusion. 
  

  

  The 
  Lower 
  Tongrian, 
  as 
  is 
  well 
  known, 
  has 
  no 
  marine 
  repre- 
  

   sentative 
  in 
  the 
  Paris 
  basin, 
  the 
  great 
  freshwater 
  gypseous 
  series 
  

   occurring 
  on 
  this 
  horizon 
  ; 
  but 
  in 
  the 
  small 
  basin 
  of 
  the 
  Cotentin, 
  as 
  

   M. 
  G. 
  Dollfus 
  has 
  so 
  well 
  shown, 
  the 
  Lower 
  Tongrian 
  or 
  Brocken- 
  

   hurst 
  series 
  is 
  represented 
  by 
  the 
  " 
  argile 
  a 
  Corbules" 
  f. 
  

  

  The 
  Headon 
  series, 
  including 
  both 
  the 
  sands 
  and 
  overlying 
  

   clays, 
  contains 
  a 
  fauna 
  which, 
  by 
  Hebert, 
  Sandberger, 
  Mayer, 
  and 
  

   other 
  authors, 
  has 
  been 
  recognized 
  under 
  the 
  name 
  of 
  the 
  zone 
  of 
  

   Cerithium 
  concavum. 
  The 
  Brockenhurst 
  series 
  contains 
  a 
  fauna 
  

   which 
  has 
  been 
  quite 
  as 
  universally 
  recognized 
  as 
  agreeing 
  with 
  that 
  

   of 
  the 
  continental 
  Tongrian 
  or 
  Lower 
  Oligocene. 
  

  

  Now, 
  if 
  my 
  interpretation 
  of 
  the 
  section 
  be 
  the 
  true 
  one, 
  the 
  beds 
  

   containing 
  the 
  Tongrian 
  fauna 
  in 
  the 
  Hampshire 
  basin 
  overlie 
  those 
  

   containing 
  the 
  fauna 
  of 
  the 
  zone 
  of 
  Cerithium 
  concavum 
  ; 
  and 
  this 
  

   is 
  the 
  relation 
  which 
  is 
  believed 
  to 
  exist 
  between 
  their 
  continental 
  

   representatives. 
  Most 
  geologists, 
  indeed, 
  group 
  the 
  zone 
  of 
  Ceri- 
  

   thium 
  concavum 
  with 
  the 
  Upper 
  Eocene 
  or 
  Bartonian, 
  and 
  the 
  repre- 
  

   sentatives 
  of 
  our 
  Brockenhurst 
  series 
  with 
  the 
  Lower 
  Oligocene. 
  

  

  But, 
  according 
  to 
  the 
  views 
  of 
  Messrs. 
  Keeping 
  and 
  Tawney, 
  the 
  

   beds 
  which 
  in 
  this 
  country 
  contain 
  the 
  Lower 
  Oligocene 
  fauna 
  

  

  * 
  I 
  have 
  pointed 
  out 
  that 
  the 
  several 
  geological 
  horizons 
  in 
  the 
  Oligocene 
  

   are 
  characterized 
  by 
  different 
  forms 
  of 
  Cerithium, 
  just 
  as 
  different 
  zones 
  in 
  the 
  

   Mesozoic 
  rocks 
  are 
  characterized 
  by 
  different 
  species 
  of 
  Ammonites. 
  My 
  critics 
  

   take 
  the 
  same 
  exception 
  to 
  my 
  views 
  as 
  has 
  been 
  urged 
  by 
  those 
  who 
  oppose 
  

   the 
  zonal 
  classification 
  of 
  the 
  Jurassic 
  rocks 
  : 
  they 
  assert 
  that 
  C. 
  concavum 
  is 
  

   occasionally 
  found 
  at 
  higher 
  horizons 
  than 
  the 
  zone 
  of 
  C. 
  concavum. 
  While 
  

   C. 
  concavum 
  occurs 
  in 
  prodigious 
  abundance 
  in 
  the 
  Headon 
  clays 
  and 
  sands, 
  it 
  

   is 
  exceedingly 
  rare 
  at 
  Colwell 
  Bay, 
  and 
  altogether 
  absent 
  at 
  Whitecliff 
  Bay 
  and 
  

   the 
  New 
  Forest 
  localities. 
  

  

  t 
  Mem. 
  Soc. 
  Greol. 
  de 
  Normandie, 
  1880, 
  p. 
  510. 
  

  

  