﻿ON 
  THE 
  SUBDIVISIONS 
  OF 
  THE 
  SPEETON 
  CLAY. 
  575 
  

  

  36. 
  On 
  the 
  Subdivisions 
  of 
  the 
  Speeton 
  Clay. 
  By 
  G. 
  W. 
  

   Lamplugh, 
  Esq. 
  (Read 
  March 
  6, 
  1889.) 
  

  

  (Communicated 
  by 
  Clement 
  Reid, 
  Esq., 
  F.G.S.) 
  

  

  Introduction. 
  

  

  Twenty 
  years 
  ago 
  Professor 
  J. 
  W. 
  Judd, 
  in 
  a 
  paper 
  * 
  which 
  has 
  

   become 
  classical, 
  described 
  to 
  this 
  Society 
  the 
  Clays 
  which 
  emerge 
  

   from 
  beneath 
  the 
  Chalk 
  at 
  Speeton 
  on 
  the 
  coast 
  of 
  Yorkshire, 
  and 
  

   showed 
  that 
  they 
  comprise 
  the 
  fullest 
  development 
  of 
  marine 
  beds 
  

   of 
  Lower 
  Cretaceous 
  or 
  Neocomian 
  age 
  to 
  be 
  found 
  in 
  England 
  ; 
  and, 
  

   in 
  a 
  later 
  paper 
  f, 
  he 
  pointed 
  out 
  that 
  the 
  section 
  at 
  this 
  place 
  

   furnished 
  the 
  key 
  by 
  means 
  of 
  which 
  might 
  be 
  identified 
  the 
  more 
  

   or 
  less 
  isolated 
  and 
  fragmentary 
  exposures 
  of 
  beds 
  of 
  this 
  age 
  

   scattered 
  over 
  the 
  whole 
  of 
  the 
  great 
  North-European 
  area. 
  He 
  

   showed, 
  moreover, 
  more 
  clearly 
  than 
  had 
  hitherto 
  been 
  done, 
  that 
  

   the 
  uppermost 
  beds 
  of 
  the 
  Jurassic 
  formation 
  were 
  also 
  represented 
  

   in 
  the 
  series, 
  and 
  denned 
  the 
  limits 
  of 
  the 
  two 
  systems. 
  

  

  In 
  spite 
  of 
  the 
  acknowledged 
  importance 
  of 
  the 
  section 
  and 
  the 
  

   uncertainty 
  which 
  still 
  pertained 
  to 
  parts 
  of 
  it, 
  there 
  has 
  been 
  

   practically 
  no 
  addition 
  to 
  our 
  knowledge 
  of 
  the 
  locality 
  since 
  these 
  

   papers 
  were 
  published 
  — 
  the 
  reason 
  for 
  this 
  being, 
  no 
  doubt, 
  the 
  

   generally 
  obscure 
  and 
  difficult 
  state 
  of 
  the 
  cliffs, 
  as 
  it 
  is 
  rarely, 
  

   except 
  in 
  the 
  winter 
  or 
  in 
  stormy 
  weather 
  when 
  this 
  bleak 
  coast- 
  

   line 
  has 
  few 
  visitors, 
  that 
  the 
  conditions 
  of 
  the 
  section 
  are 
  favourable 
  

   for 
  observation. 
  

  

  It 
  needs 
  a 
  high 
  and 
  stormy 
  tide, 
  to 
  reveal 
  a 
  fresh 
  unweathered 
  

   surface 
  of 
  clay 
  at 
  the 
  foot 
  of 
  the 
  slopes, 
  or 
  a 
  heavy 
  onshore 
  gale, 
  to 
  

   sweep 
  aside 
  the 
  sand 
  and 
  shingle 
  of 
  the 
  beach, 
  before 
  the 
  student 
  of 
  

   the 
  section 
  can 
  make 
  any 
  really 
  satisfactory 
  progress 
  either 
  in 
  col- 
  

   lecting 
  the 
  fossils 
  or 
  in 
  studying 
  the 
  sequence 
  of 
  the 
  deposits 
  ; 
  and 
  

   many 
  repetitions 
  of 
  such 
  conditions 
  are 
  necessary 
  before 
  the 
  many 
  

   difficulties 
  of 
  the 
  section 
  can 
  be 
  grasped. 
  Eor 
  work 
  of 
  this 
  kind, 
  

   which 
  can 
  only 
  be 
  carried 
  on 
  at 
  intervals, 
  it 
  is 
  almost 
  indispensable 
  

   that 
  the 
  observer 
  should 
  live 
  near 
  the 
  locality 
  ; 
  and 
  it 
  is 
  because 
  of 
  the 
  

   opportunities 
  I 
  have 
  had 
  during 
  the 
  last 
  ten 
  years, 
  by 
  residence 
  in 
  the 
  

   neighbourhood, 
  that 
  I 
  have 
  been 
  able 
  to 
  accumulate 
  the 
  observations 
  

   which 
  I 
  propose 
  to 
  summarize 
  in 
  this 
  paper. 
  Even 
  now, 
  as 
  will 
  be 
  

   found, 
  my 
  knowledge 
  of 
  the 
  section 
  does 
  not 
  include 
  quite 
  the 
  whole 
  

   of 
  the 
  clays, 
  but 
  many 
  more 
  years 
  might 
  have 
  elapsed 
  had 
  I 
  waited 
  

   to 
  make 
  it 
  complete. 
  

  

  Bibliography. 
  

  

  The 
  bibliography 
  and 
  history 
  of 
  the 
  beds 
  up 
  to 
  the 
  date 
  of 
  publi- 
  

   cation 
  of 
  Professor 
  Judd's 
  first 
  paper, 
  in 
  1868, 
  were 
  thoroughly 
  

  

  * 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxiv. 
  p. 
  219. 
  

   t 
  Ibid. 
  vol. 
  xxvi. 
  p. 
  326. 
  

   Q.J.G.S. 
  No. 
  180. 
  2u 
  

  

  