﻿726 
  SEARLES 
  V. 
  WOOD 
  ON 
  THE 
  NEWER 
  

  

  position 
  it 
  now 
  occupies, 
  the 
  two 
  areas 
  being 
  connected 
  by 
  the 
  

   continuation 
  of 
  this 
  line 
  through 
  the 
  Isle 
  of 
  Purbeck. 
  The 
  exces- 
  

   sive 
  denudation 
  which 
  has 
  taken 
  place 
  along 
  this 
  line 
  of 
  upthrow 
  

   and 
  left 
  the 
  gravel 
  on 
  the 
  Chalk 
  Down 
  behind 
  Portland 
  in 
  a 
  similar 
  

   position 
  to 
  that 
  which 
  it 
  occupies 
  on 
  Headon 
  and 
  Cassar's 
  Camp 
  

   Hills, 
  I 
  attribute 
  to 
  the 
  selective 
  action 
  of 
  the 
  sea, 
  beneath 
  which 
  

   the 
  movement 
  took 
  place, 
  on 
  the 
  strata 
  which 
  were 
  shattered 
  by 
  it, 
  

   and 
  brought 
  under 
  this 
  action 
  by 
  the 
  continuous 
  though 
  gradual 
  

   rise 
  of 
  the 
  shattered 
  sea-bottom, 
  during 
  Stages 
  III. 
  to 
  Y. 
  ; 
  but 
  Prof. 
  

   Prestwich 
  seems 
  to 
  attribute 
  it 
  to 
  atmospheric 
  agency. 
  

  

  To 
  the 
  south 
  of 
  this 
  upthrown 
  and 
  denuded 
  space 
  is 
  the 
  high- 
  

   land 
  of 
  Portland, 
  on 
  the 
  seaward 
  slope 
  of 
  which 
  lies 
  the 
  old 
  beach 
  

   up 
  to 
  the 
  foot 
  of 
  the 
  buried 
  cliff 
  (e 
  of 
  cut 
  viii.) 
  ; 
  while 
  at 
  the 
  foot 
  of 
  

   the 
  landward 
  slope 
  of 
  this 
  high-land 
  *, 
  and 
  skirting 
  the 
  south 
  of 
  

   this 
  denuded 
  space, 
  Mr. 
  Prestwich 
  shows 
  a 
  very 
  thick 
  talus 
  of 
  the 
  

   burying 
  material, 
  or 
  " 
  Landwash 
  " 
  as 
  he 
  proposes 
  to 
  call 
  it, 
  identical 
  

   with 
  d 
  of 
  the 
  cut, 
  in 
  which 
  he 
  says 
  fragments 
  occur 
  of 
  the 
  Middle 
  

   Purbeck 
  beds 
  which 
  are 
  now 
  not 
  to 
  be 
  found 
  in 
  situ 
  on 
  this 
  high-land 
  ; 
  

   and 
  it 
  is 
  on 
  this 
  that 
  he 
  mainly 
  founds 
  his 
  opinion 
  that 
  the 
  material 
  

   of 
  this 
  talus, 
  and 
  that 
  corresponding 
  to 
  it 
  (marked 
  d 
  in 
  the 
  cut), 
  under 
  

   which 
  the 
  cliff 
  is 
  buried 
  has 
  had 
  a 
  marine 
  origin, 
  and 
  is 
  the 
  result 
  

   of 
  that 
  submergence 
  of 
  1000 
  feet 
  or 
  more, 
  of 
  which, 
  in 
  the 
  subsequent 
  

   paper 
  read 
  before 
  the 
  British 
  Association 
  meeting 
  of 
  1880, 
  he 
  speaks. 
  

   This 
  " 
  Landwash 
  " 
  contains, 
  he 
  says, 
  land-shells 
  in 
  intercalated 
  

   seams 
  of 
  loam, 
  and 
  mammalian 
  remains. 
  Prof. 
  Prestwich 
  thus 
  assigns 
  

   the 
  Newer 
  Pliocene 
  submergence 
  to 
  a 
  very 
  much 
  later 
  date 
  than 
  1 
  do 
  

   (unless 
  it 
  be 
  that 
  he 
  considers 
  this 
  great 
  submergence 
  to 
  have 
  taken 
  

   place 
  twicef, 
  which 
  I 
  do 
  not), 
  and 
  he 
  refers 
  to 
  it 
  as 
  its 
  evidence, 
  

   not 
  the 
  gravel 
  which 
  in 
  the 
  successive 
  stages 
  of 
  its 
  emergence 
  forms 
  

   so 
  large 
  a 
  part 
  of 
  the 
  subject 
  of 
  my 
  memoir, 
  but 
  an 
  accumulation 
  

   which 
  appears 
  to 
  me 
  to 
  be 
  exclusively 
  of 
  terrestrial 
  origin. 
  With 
  

   respect 
  to 
  this 
  accumulation 
  and 
  the 
  burying 
  of 
  the 
  cliffs 
  under 
  it, 
  

   I 
  have 
  already 
  observed 
  that 
  cliffs 
  of 
  such 
  yielding 
  material 
  as 
  chalk 
  

   or 
  marl 
  could 
  not 
  escape 
  being 
  planed 
  off 
  by 
  a 
  submergence; 
  and 
  

   though 
  the 
  cliffs 
  of 
  Portland 
  and 
  Sili 
  Bay 
  are 
  of 
  more 
  unyielding 
  

   material 
  than 
  those 
  of 
  the 
  Isle 
  of 
  Wight 
  Foreland, 
  Brighton, 
  or 
  

   Sangatte, 
  yet 
  if 
  one 
  of 
  these 
  was 
  buried 
  by 
  submergence, 
  so 
  were 
  

  

  * 
  From 
  the 
  representation 
  which 
  Mr. 
  Prestwich 
  gives 
  of 
  this 
  talus, 
  it 
  seems 
  

   to 
  me 
  that 
  traces 
  of 
  the 
  old 
  shore-line 
  represented 
  by 
  the 
  cliff 
  and 
  shingle 
  may 
  

   not 
  unlikely 
  be 
  concealed 
  under 
  it, 
  though 
  he 
  regards 
  the 
  hollow 
  it 
  occupies 
  as 
  

   all 
  originating 
  since 
  the 
  cliff. 
  

  

  t 
  In 
  a 
  paper 
  read 
  before 
  the 
  British 
  Association 
  meeting 
  of 
  the 
  following 
  year 
  

   (1881), 
  Prof. 
  Prestwich 
  describes 
  the 
  submergence 
  of 
  the 
  South 
  of 
  England 
  as 
  

   having 
  taken 
  place 
  during 
  the 
  formation 
  of 
  the 
  pebbly 
  sand 
  b\, 
  which, 
  though 
  

   I 
  do 
  not 
  agree 
  in 
  many 
  of 
  the 
  details, 
  is 
  substantially 
  what 
  I 
  had 
  previously 
  

   shown, 
  in 
  the 
  first 
  part 
  of 
  this 
  memoir, 
  in 
  connexion 
  with 
  this 
  sand 
  and 
  its 
  

   modification 
  in 
  Norfolk 
  into 
  the 
  Till 
  and 
  Contorted 
  Drift, 
  and 
  its 
  representation 
  

   southwards 
  and 
  westwards 
  by 
  the 
  gravel 
  b\ 
  as 
  submergence 
  proceeded. 
  I 
  can 
  

   only 
  therefore 
  infer 
  that 
  Prof. 
  Prestwich 
  regards 
  this 
  great 
  submergence 
  as 
  

   having 
  been 
  repeated, 
  when 
  the 
  cliffs 
  were 
  buried 
  late 
  in 
  the 
  Newer 
  Pliocene 
  

   period. 
  

  

  