﻿CORRELATION 
  OF 
  THE 
  BOURNEMOUTH 
  BEDS. 
  11 
  

  

  have 
  been 
  mainly 
  derived 
  from 
  an 
  old 
  rock 
  area. 
  There 
  are 
  no 
  indi- 
  

   cations 
  of 
  the 
  proximity 
  of 
  salt 
  water, 
  beyond 
  the 
  occurrence 
  of 
  bored 
  

   wood 
  ; 
  and 
  although 
  this 
  is 
  met 
  with 
  in 
  existing 
  rivers 
  even 
  300 
  

   miles 
  from 
  the 
  sea, 
  its 
  presence 
  must 
  imply 
  that 
  this 
  region 
  was 
  

   towards 
  the 
  lower 
  part 
  of 
  the 
  course 
  of 
  the 
  river, 
  although 
  little 
  

   influenced, 
  I 
  believe, 
  by 
  tides. 
  

  

  If 
  this 
  were 
  admitted 
  to 
  be 
  the 
  filling-in 
  of 
  the 
  main 
  channel, 
  the 
  

   remainder 
  of 
  the 
  cliff-section 
  would 
  have 
  been 
  formed 
  in 
  a 
  valley 
  not 
  

   continuously 
  subjected 
  to 
  the 
  action 
  of 
  running 
  water. 
  The 
  clay 
  

   patches 
  would 
  mark 
  pools 
  or 
  slack 
  water 
  creeks 
  ; 
  and 
  while 
  it 
  is 
  quite 
  

   possible 
  that 
  those 
  without 
  fossils, 
  and 
  especially 
  those 
  that 
  are 
  not 
  

   laminated, 
  may 
  have 
  been 
  deposited 
  in 
  depressions 
  at 
  the 
  bottom 
  of 
  

   the 
  river 
  itself, 
  it 
  is 
  certain 
  that 
  those 
  with 
  an 
  abundance 
  of 
  leaves 
  

   smoothly 
  deposited 
  must 
  have 
  been 
  formed 
  away 
  from 
  the 
  influence 
  

   of 
  strong 
  currents, 
  and 
  in 
  sidings 
  of, 
  or 
  pools 
  left 
  by, 
  the 
  river. 
  The 
  

   clays 
  are 
  of 
  all 
  shades, 
  from 
  white 
  to 
  black, 
  the 
  more 
  considerable 
  

   masses 
  being 
  always 
  dark. 
  The 
  pure 
  sediments 
  of 
  the 
  river 
  and 
  its 
  

   sands 
  were 
  white 
  ; 
  and 
  we 
  therefore 
  cannot 
  but 
  infer 
  that 
  the 
  staining- 
  

   matter 
  of 
  the 
  dark 
  masses 
  was 
  iron 
  and 
  carbon, 
  derived 
  from 
  decay- 
  

   ing 
  vegetation. 
  In 
  the 
  case 
  of 
  the 
  leaf-beds 
  the 
  dark 
  clays 
  always 
  

   have 
  lighter 
  layers 
  between 
  them 
  and 
  the 
  sands 
  which 
  surround 
  them, 
  

   and 
  these 
  contain 
  the 
  best-preserved 
  leaves. 
  I 
  have 
  seen 
  no 
  instance 
  

   of 
  the 
  dark 
  clays 
  enclosing 
  lighter 
  layers, 
  nor 
  of 
  their 
  ever, 
  when 
  

   undisturbed, 
  coming 
  into 
  direct 
  contact 
  with 
  the 
  sands 
  or 
  grits 
  *. 
  The 
  

   presence 
  of 
  leaves 
  in 
  the 
  lighter 
  beds 
  shows 
  at 
  least 
  that 
  vegetable 
  

   matter 
  reached 
  the 
  pools 
  in 
  some 
  abundance, 
  and 
  their 
  absence 
  in 
  the 
  

   blacker 
  clays 
  that 
  they 
  had 
  decomposed 
  into 
  staining-matter. 
  The 
  

   section 
  of 
  the 
  beds 
  just 
  west 
  of 
  the 
  pier 
  presents 
  at 
  its 
  base 
  fine 
  river- 
  

   sand, 
  becoming 
  carbonaceous 
  as 
  the 
  current 
  diminished, 
  then 
  choked 
  

   with 
  the 
  fallen 
  leaves, 
  and 
  then 
  a 
  nearly 
  stagnant 
  pool. 
  The 
  deposi- 
  

   tion 
  of 
  mud 
  was 
  abruptly 
  ended 
  by 
  an 
  influx 
  of 
  coarse 
  grit 
  several 
  feet 
  

   in 
  depth. 
  The 
  same 
  process 
  was 
  repeated 
  in 
  the 
  second 
  leaf 
  -bed 
  ; 
  but 
  

   the 
  third 
  pool 
  was 
  formed 
  more 
  suddenly 
  ; 
  for 
  the 
  clay 
  rests 
  immedi- 
  

   ately 
  on 
  clean 
  grit 
  and 
  is 
  not 
  discoloured, 
  though 
  leaf-impressions 
  

   abound 
  in 
  it. 
  It 
  is 
  margined, 
  like 
  a 
  few 
  other 
  leaf-beds 
  here, 
  with 
  

   a 
  white 
  marl 
  penetrated 
  by 
  rootlets. 
  The 
  succeeding 
  5 
  feet 
  of 
  coarse 
  

   granitic 
  grit 
  mark 
  the 
  passage 
  of 
  a 
  considerable 
  body 
  of 
  water, 
  and 
  of 
  

   some 
  swiftness, 
  and 
  the 
  ironstone 
  a 
  period 
  of 
  stagnation. 
  The 
  white 
  

   clay 
  shows 
  that 
  water 
  again 
  trickled 
  in, 
  charged 
  with 
  enough 
  sedi- 
  

   ment 
  to 
  bury 
  the 
  leaves 
  before 
  they 
  decayed. 
  This 
  passes 
  gradually 
  

   into 
  the 
  black 
  clay, 
  small 
  light 
  patches 
  with 
  actually 
  skeletonized 
  

   leaves 
  in 
  them 
  (one 
  has 
  yielded 
  a 
  unique 
  Cecropia 
  leaf, 
  and 
  another 
  a 
  

   fern, 
  Adiantwm(Hewardia) 
  regia) 
  penetrating 
  the 
  black 
  stagnant 
  clay, 
  

   which 
  is 
  dark 
  with 
  decomposed 
  vegetation 
  and 
  charged 
  with 
  sulphide 
  

   of 
  iron. 
  In 
  some 
  layers 
  ferns 
  and 
  seeds 
  can 
  still 
  be 
  traced 
  ; 
  but 
  in 
  

   most 
  the 
  vegetable 
  matter 
  is 
  thoroughly 
  decayed. 
  Layers 
  of 
  com- 
  

   pact 
  clay 
  are 
  separated 
  by 
  what 
  are 
  now 
  films 
  of 
  carbonaceous 
  mat- 
  

   ter, 
  to 
  the 
  number 
  of 
  hundreds, 
  each 
  layer 
  indicating 
  possibly 
  only 
  

  

  * 
  Dark-clay 
  masses 
  sometimes 
  contain 
  galls 
  of 
  the 
  finest 
  pipe-clay, 
  due, 
  I 
  

   belieye, 
  to 
  segregation. 
  

  

  