﻿452 
  MB. 
  S. 
  S. 
  BUCKMAN 
  ON 
  THE 
  

  

  At 
  Down 
  Cliffs, 
  about 
  three 
  miles 
  from 
  this 
  locality, 
  we 
  are 
  able 
  

   to 
  find 
  the 
  continuation 
  of 
  this 
  section, 
  although 
  the 
  exposure 
  is 
  

   not 
  very 
  good, 
  and 
  I 
  was 
  not 
  able 
  to 
  work 
  it 
  thoroughly. 
  

  

  IX. 
  a. 
  Section 
  at 
  Doivn 
  Cliffs, 
  near 
  Seatoivn, 
  Dorset. 
  

  

  ft. 
  

  

  Upper 
  Lias. 
  

  

  18 
  Yellow 
  sands, 
  a 
  continuation 
  of 
  those 
  seen 
  in 
  

   the 
  last 
  Section, 
  passing 
  gradually 
  into 
  a 
  

  

  19. 
  Blue, 
  somewhat 
  micaceous 
  clay. 
  No 
  fossils 
  

  

  were 
  observed. 
  Thickness 
  about 
  70-80 
  

  

  20. 
  Pink-coloured 
  rock 
  with 
  Hildoceras 
  bifrons 
  ; 
  

   attached 
  to 
  a 
  rock 
  like 
  marlstone. 
  

  

  The 
  first 
  thing 
  which 
  must 
  strike 
  us 
  on 
  examining 
  these 
  sections 
  

   is 
  the 
  totally 
  different 
  faunas 
  which 
  Xos. 
  III. 
  and 
  VIII. 
  exhibit 
  — 
  

   sections 
  which 
  show 
  the 
  junction 
  of 
  the 
  so-called 
  " 
  Midford 
  Sands 
  " 
  

   with 
  Upper 
  Lias 
  Clay. 
  Not 
  one 
  species 
  do 
  they 
  possess 
  in 
  common. 
  

   The 
  Yeovil 
  Sands 
  (Section 
  VII.) 
  overlie 
  a 
  fossiliferous 
  bed 
  ; 
  and 
  if 
  we 
  

   seek 
  in 
  the 
  section 
  at 
  Xibley 
  for 
  the 
  same 
  fauna 
  which 
  that 
  bed 
  con- 
  

   tains, 
  we 
  find 
  it, 
  not 
  below, 
  but 
  above, 
  the 
  Cotteswold 
  Sands. 
  Here 
  

   we 
  have, 
  to 
  start 
  with, 
  the 
  great 
  and 
  fundamental 
  difference 
  between 
  

   the 
  position 
  and 
  palaeontology 
  of 
  the 
  Yeovil 
  and 
  the 
  Cotteswold 
  Sands. 
  

   These 
  two 
  little 
  sections 
  (Xos. 
  ILL 
  and 
  VII.), 
  both, 
  as 
  it 
  happens, 
  

   taken 
  from 
  exposures 
  by 
  the 
  roadside, 
  are, 
  after 
  all, 
  the 
  two 
  most 
  

   important 
  sections 
  in 
  the 
  series. 
  They 
  supply 
  the 
  keynotes 
  to 
  the 
  

   situation 
  ; 
  the 
  others 
  give 
  us 
  general 
  details. 
  

  

  In 
  the 
  first 
  column 
  of 
  the 
  various 
  sections 
  I 
  have 
  placed 
  the 
  usual 
  

   lithological 
  signification 
  under 
  which 
  the 
  strata 
  have 
  passed. 
  In 
  

   the 
  second 
  column 
  I 
  have 
  appended 
  certain 
  names 
  to 
  the 
  beds, 
  for 
  

   the 
  purpose 
  of 
  distinction, 
  taken 
  from 
  some 
  characteristic 
  Ammonite 
  *. 
  

  

  Going 
  through 
  the 
  sections 
  in 
  order, 
  we 
  shall 
  find 
  that 
  the 
  

   sandy 
  strata 
  continue 
  to 
  begin 
  later, 
  and 
  to 
  end 
  later, 
  in 
  regard 
  to 
  

   the 
  palaeontological 
  evidence 
  as 
  expressed 
  in 
  the 
  second 
  column. 
  

   Sections 
  II. 
  and 
  III. 
  show 
  us 
  the 
  position 
  of 
  the 
  Cotteswold 
  Sands 
  in 
  

   the 
  Haresfield-Wotton 
  district, 
  this 
  position 
  being 
  below 
  the 
  Striatu- 
  

   Zmw-beds. 
  In 
  the 
  Sodbury 
  district 
  (Section 
  IV.) 
  the 
  sands 
  did 
  not 
  end 
  

   until 
  the 
  Dispansum-be&s 
  had 
  been 
  deposited. 
  In 
  the 
  Bath 
  district 
  

   (Section 
  V.) 
  we 
  do 
  not 
  know 
  the 
  time 
  of 
  the 
  ending 
  of 
  the 
  Midford 
  

   Sands 
  ; 
  but 
  they 
  differ 
  totally 
  from 
  the 
  Cotteswold 
  Sands 
  proper, 
  in 
  

   that 
  they 
  did 
  not 
  begin 
  until 
  the 
  Striatuliim-'beds 
  had 
  been 
  deposited. 
  

   In 
  the 
  Ilminster 
  district 
  (Section 
  VII.) 
  the 
  Yeovil 
  Sands 
  did 
  not 
  begin 
  

   until 
  the 
  Dispjansum-beds 
  had 
  been 
  laid 
  down, 
  while 
  their 
  ending, 
  

   as 
  we 
  can 
  find 
  out 
  from 
  Burton 
  Bradstock 
  (Section 
  IX.), 
  from 
  Broad 
  

   "Windsor, 
  and 
  Stoke 
  Knap, 
  occurs 
  towards 
  the 
  top 
  of 
  the 
  Opalinum- 
  

   zone. 
  

  

  * 
  It 
  is 
  not 
  intended 
  to 
  state 
  that 
  the 
  Ammonite 
  of 
  which 
  the 
  name 
  is 
  used 
  

   is 
  confined 
  to 
  that 
  horizon 
  ; 
  but 
  merely 
  that 
  it 
  is 
  most 
  characteristic 
  thereof, 
  

   that, 
  in 
  fact, 
  it 
  is 
  the 
  dominant 
  species. 
  The 
  word 
  " 
  beds 
  " 
  is 
  used 
  in 
  a 
  different 
  

   sense 
  to 
  "zone," 
  and 
  is 
  in 
  no 
  way 
  necessarily 
  equivalent 
  thereto. 
  For 
  instance, 
  

   the 
  OpoJinum-heds 
  and 
  the 
  J/cwm'-becls 
  are 
  parts 
  of 
  the 
  Opalini/m-zone. 
  

  

  