﻿328 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [A]M*. 
  1**, 
  

  

  The 
  cliff 
  is 
  a 
  curve, 
  partly 
  running 
  nearly 
  due 
  north 
  and 
  south, 
  

   and 
  partly 
  facing 
  more 
  to 
  the 
  east 
  ; 
  so, 
  as 
  the 
  deposit 
  rises 
  from 
  the 
  

   beach 
  at 
  the 
  eastern 
  end, 
  its 
  dip 
  is 
  south-easterly. 
  

  

  All 
  observers 
  concur 
  in 
  making 
  its 
  thickness 
  about 
  four 
  feet, 
  

   which 
  is 
  maintained 
  from 
  one 
  end 
  of 
  the 
  section 
  to 
  the 
  other. 
  But 
  

   this 
  is 
  not 
  all 
  one 
  layer 
  ; 
  for 
  throughout 
  the 
  cliff 
  the 
  Red 
  Rock 
  is 
  seen 
  

   to 
  consist 
  of 
  three 
  subdivisions 
  of 
  about 
  equal 
  thickness, 
  and 
  in 
  

   many 
  places 
  so 
  well 
  parted 
  by 
  bedding 
  as 
  to 
  form, 
  by 
  falling 
  of 
  the 
  

   cliff, 
  three 
  overhanging 
  cornices, 
  the 
  uppermost 
  of 
  which 
  is 
  often 
  

   similarly 
  overhung 
  by 
  the 
  white 
  sponge-rock 
  band 
  above. 
  

  

  Into 
  the 
  lower 
  of 
  these 
  beds 
  (which 
  I 
  will 
  call 
  No. 
  3), 
  as 
  in 
  the 
  

   others, 
  the 
  little 
  brown 
  and 
  black 
  shining 
  pebbles, 
  which 
  form 
  so 
  

   conspicuous 
  a 
  feature 
  in 
  the 
  Carstone 
  sands, 
  pass 
  up, 
  and 
  are 
  almost 
  

   as 
  numerous 
  in 
  the 
  Huns'ton 
  Red 
  Rock 
  as 
  in 
  the 
  underlying 
  beds. 
  

   In 
  slipping 
  and 
  falling, 
  too, 
  the 
  Red 
  Rock 
  almost 
  invariably 
  goes 
  

   with 
  the 
  Carstone, 
  as 
  though 
  they 
  were 
  one 
  formation, 
  while 
  cracks 
  

   and 
  fissures 
  in 
  the 
  chalk 
  do 
  not 
  affect 
  the 
  red 
  beds. 
  The 
  sponge- 
  

   band 
  always 
  follows 
  the 
  jointing 
  of 
  the 
  other 
  white 
  chalk. 
  

  

  The 
  uppermost 
  of 
  the 
  three 
  layers 
  has 
  the 
  physical 
  characters 
  of 
  

   chalk, 
  breaking 
  by 
  joints, 
  which 
  present, 
  on 
  the 
  cliff-face, 
  long 
  flat 
  

   surfaces. 
  The 
  middle 
  bed 
  (No. 
  2) 
  has 
  a 
  remarkable 
  nodular 
  con- 
  

   cretionary 
  character, 
  which 
  makes 
  its 
  surface 
  on 
  the 
  cliff 
  rugged. 
  

   These 
  concretions 
  are 
  of 
  phosphate 
  of 
  lime 
  ; 
  one 
  of 
  them, 
  analyzed 
  

   by 
  Professor 
  Liveing, 
  yielded 
  11 
  per 
  cent, 
  of 
  that 
  substance. 
  The 
  

   lower 
  layer 
  is 
  sandy, 
  and 
  not 
  more 
  clearly 
  separated 
  from 
  the 
  Car- 
  

   stone 
  below 
  than 
  from 
  the 
  concretionary 
  layer 
  above 
  ; 
  for 
  the 
  line 
  of 
  

   junction 
  is 
  only 
  marked 
  by 
  colour, 
  being 
  otherwise 
  quite 
  indistin- 
  

   guishable, 
  and 
  not 
  affected 
  by 
  weathering. 
  

  

  The 
  upper 
  bed 
  is 
  divided 
  into 
  two 
  by 
  a 
  bedding 
  which 
  is 
  not 
  

   smooth, 
  but 
  nodular. 
  As 
  the 
  colour 
  is 
  due 
  to 
  glauconite, 
  it 
  is 
  pos- 
  

   sible 
  the 
  bedding 
  may 
  be 
  owing 
  to 
  the 
  same 
  cause. 
  The 
  top 
  surface 
  

   is 
  wrinkled 
  and 
  subnodular. 
  

  

  The 
  prevailing 
  character 
  of 
  colour 
  in 
  bed 
  No. 
  1, 
  in 
  which 
  the 
  

   ramose 
  sponge 
  chiefly 
  abounds, 
  is 
  mottled, 
  and, 
  by 
  weathering, 
  large 
  

   patches 
  of 
  it 
  become 
  quite 
  white. 
  It 
  nearly 
  resembles 
  in 
  structure 
  

   the 
  sponge 
  -stratum 
  above, 
  differing 
  chiefly 
  in 
  being 
  something 
  more 
  

   compact, 
  and 
  divided 
  by 
  larger 
  and 
  cleaner 
  joints. 
  

  

  Sometimes 
  the 
  sponge-layer 
  quite 
  touches 
  the 
  Red 
  Rock; 
  but 
  

   often 
  there 
  is 
  a 
  thin 
  soapy 
  seam 
  of 
  deep 
  -red 
  matter, 
  less 
  than 
  an 
  

   inch 
  thick, 
  parting 
  them 
  ; 
  and 
  at 
  intervals 
  this 
  enlarges 
  into 
  nest- 
  

   like 
  burrows, 
  which 
  penetrate 
  far, 
  and 
  extend 
  several 
  inches 
  up 
  

   into 
  the 
  sponge-rock, 
  without 
  affecting 
  the 
  level 
  top 
  of 
  the 
  Red 
  

   Rock. 
  Most 
  commonly 
  these 
  spaces 
  are 
  filled 
  with 
  soft 
  matter 
  of 
  a 
  

   deep-red 
  tinge, 
  but 
  sometimes 
  with 
  sand 
  ; 
  and 
  when 
  this 
  is 
  washed 
  

   out 
  by 
  the 
  surf, 
  the 
  holes 
  are 
  seen 
  to 
  anastomose. 
  The 
  nests 
  do 
  not 
  

   affect 
  the 
  colour 
  of 
  the 
  bed 
  underneath 
  ; 
  and 
  where 
  the 
  red 
  matter, 
  

   soft 
  or 
  concretionary, 
  joins 
  the 
  white 
  sponge-band, 
  the 
  limit 
  of 
  the 
  

   colour 
  is 
  sharp 
  and 
  clean. 
  

  

  The 
  sand 
  and 
  coloured 
  soapy 
  matter 
  are 
  far 
  from 
  being 
  confined 
  

   to 
  the 
  top 
  of 
  the 
  Red 
  Rock 
  ; 
  for 
  they 
  occur 
  at 
  the 
  top 
  of 
  the 
  white 
  

  

  