﻿684 
  SEARLES 
  V. 
  WOOD 
  ON 
  THE 
  ]S 
  T 
  EWER 
  

  

  south 
  of 
  England, 
  so 
  as 
  to 
  pass 
  exclusively 
  along 
  the 
  west 
  of 
  the 
  

   "Wold 
  in 
  Lincolnshire, 
  sweeping 
  all 
  the 
  degraded 
  chalk 
  from 
  the 
  

   Wold 
  into 
  this 
  Lincolnshire 
  vale, 
  and 
  carrying 
  it 
  down 
  into 
  Sheet 
  83, 
  

   where 
  it 
  is 
  heaped 
  into 
  the 
  hills 
  shown 
  by 
  the 
  black 
  tint, 
  in 
  Map 
  1, 
  

   representing 
  the 
  Chalky 
  Clay 
  there. 
  Possibly, 
  though 
  I 
  do 
  not 
  think 
  

   so 
  however, 
  there 
  may 
  be 
  some 
  of 
  this 
  concealed 
  by 
  the 
  alluvium 
  

   which 
  is 
  extensively 
  spread 
  in 
  the 
  west 
  of 
  the 
  Yorkshire 
  part 
  of 
  the 
  

   Wold 
  in 
  Sheet 
  86, 
  or 
  by 
  the 
  gravel 
  which 
  covers 
  so 
  much 
  of 
  the 
  

   east 
  of 
  Sheet 
  93, 
  and 
  skirts 
  the 
  Wold 
  escarpment 
  there. 
  Prior 
  to 
  

   this 
  deflection, 
  the 
  ice 
  thus 
  filling 
  the 
  vale 
  of 
  York 
  and 
  enveloping 
  

   the 
  wold 
  issued 
  to 
  the 
  sea 
  as 
  a 
  glacier 
  through 
  the 
  Humber, 
  and 
  

   covered 
  the 
  east 
  of 
  Holderness 
  (which 
  was 
  the 
  preglacial 
  Humber 
  

   valley) 
  with 
  its 
  moraine, 
  B, 
  while 
  the 
  silt 
  and 
  chalk 
  debris 
  from 
  

   it 
  passed 
  out 
  to 
  sea 
  to 
  supply 
  the 
  material 
  of 
  the 
  Cromer 
  Till 
  (b 
  2). 
  

   As 
  the 
  ice 
  in 
  thus 
  retiring 
  from 
  the 
  Humber 
  to 
  the 
  west 
  of 
  the 
  

   Wold 
  uncovered 
  this 
  moraine, 
  the 
  sea 
  took 
  its 
  place, 
  and 
  the 
  Brid- 
  

   lington 
  and 
  Dimlington 
  Mollusca 
  established 
  themselves 
  there 
  ; 
  

   so 
  that 
  their 
  remains 
  (many 
  of 
  which 
  are 
  in 
  the 
  condition 
  in 
  which 
  

   they 
  were 
  at 
  the 
  death 
  of 
  the 
  animals) 
  became 
  imbedded 
  in 
  seams 
  

   of 
  sand 
  which 
  occur 
  near 
  the 
  top 
  of 
  B, 
  in 
  fig. 
  XL 
  VI., 
  as 
  well 
  as 
  at 
  

   Bridlington, 
  and 
  were 
  probably 
  mixed 
  up 
  in 
  this 
  part 
  of 
  the 
  moraine 
  

   by 
  oscillations 
  in 
  the 
  position 
  of 
  the 
  ice 
  as 
  it 
  was 
  thus 
  changing 
  its 
  

   direction. 
  This, 
  as 
  shown 
  by 
  the 
  character 
  of 
  these 
  shells 
  (among 
  

   which 
  are 
  two 
  extinct 
  and 
  highly 
  characteristic 
  Crag 
  forms), 
  when 
  

   compared 
  with 
  the 
  shells 
  from 
  the 
  gravels 
  at 
  1200 
  and 
  1350 
  feet 
  

   elevation, 
  must 
  have 
  been 
  before 
  the 
  culmination 
  of 
  the 
  depression 
  

   represented 
  by 
  Map 
  4 
  had 
  arrived, 
  at 
  which 
  time 
  it 
  was 
  that 
  the 
  

   masses 
  buried 
  in 
  the 
  Contorted 
  Drift 
  were 
  carried 
  into 
  it, 
  probably 
  

   from 
  the 
  great 
  accumulation 
  of 
  reconstructed 
  chalk, 
  in 
  Sheet 
  83, 
  

   already 
  referred 
  to, 
  and 
  of 
  which 
  the 
  place 
  is 
  marked 
  by 
  an 
  asterisk 
  

   in 
  that 
  map 
  * 
  ; 
  but, 
  to 
  make 
  the 
  case 
  intelligible, 
  I 
  have 
  shown 
  the 
  

  

  * 
  Mr. 
  T. 
  Mellard 
  Reade, 
  in 
  the 
  38th 
  vol. 
  of 
  the 
  Journal, 
  page 
  222, 
  seems 
  to 
  be 
  

   under 
  the 
  impression 
  that 
  these 
  masses 
  consist 
  of 
  chalk 
  ; 
  but 
  such 
  is 
  not 
  the 
  case, 
  

   though 
  the 
  sheets 
  interstratified 
  in 
  the 
  Till 
  below 
  are 
  of 
  unaltered 
  chalk, 
  and, 
  as 
  

   stated 
  in 
  the 
  first 
  part 
  of 
  this 
  memoir, 
  seem 
  to 
  have 
  been 
  dropped 
  from 
  floe-ice 
  

   early 
  in 
  Stage 
  II., 
  and 
  are 
  unconnected 
  with 
  the 
  contortions. 
  The 
  masses 
  in 
  

   question, 
  the 
  introduction 
  of 
  which 
  is 
  due 
  to 
  the 
  agency 
  giving 
  rise 
  to 
  the 
  

   contortions, 
  were 
  introduced 
  at 
  the 
  close 
  of 
  the 
  Contorted 
  Drift, 
  and 
  are 
  mostly 
  

   of 
  reconstructed 
  chalk, 
  or 
  the 
  extremely 
  chalky 
  f 
  orm 
  of 
  the 
  Chalky 
  Clay, 
  and 
  

   include 
  quartz 
  and 
  quartzite 
  pebbles 
  and 
  other 
  foreign 
  debris, 
  and 
  in 
  some 
  of 
  

   the 
  inland 
  pits 
  consist 
  of 
  a 
  deposit 
  of 
  chalk 
  silt 
  in 
  paper-like 
  laminae. 
  Where, 
  

   as 
  in 
  some 
  cases 
  by 
  the 
  flints 
  being 
  in 
  rows, 
  they 
  look 
  like 
  chalk, 
  the 
  masses 
  consist 
  

   of 
  glaciated 
  chalk 
  with 
  galls 
  of 
  red 
  clay 
  in 
  them. 
  If, 
  therefore, 
  they 
  were 
  

   introduced 
  as 
  Mr. 
  Reade 
  thinks, 
  not 
  by 
  the 
  grounding 
  of 
  bergs, 
  but 
  of 
  floe 
  

   ice, 
  these 
  floes 
  must 
  have 
  frozen 
  to 
  banks 
  of 
  moraine 
  extruded 
  at 
  or 
  about 
  

   the 
  sea-level, 
  as 
  is 
  the 
  case 
  in 
  many 
  parts 
  of 
  Greenland. 
  The 
  way 
  in 
  which 
  

   these 
  masses 
  and 
  the 
  contortions 
  cease 
  eastwards 
  along 
  the 
  North 
  -Norfolk 
  cliff 
  as 
  

   •the 
  Contorted 
  Drift 
  in 
  tbat 
  direction 
  thins, 
  shows, 
  however, 
  that 
  the 
  vehicle 
  of 
  

   their 
  transport 
  was 
  ice 
  which 
  required 
  some 
  depth 
  of 
  water 
  to 
  float 
  in. 
  I 
  am 
  

   at 
  a 
  loss 
  to 
  imagine 
  where 
  the 
  Chalk 
  can 
  be, 
  as 
  Mr. 
  Reade 
  supposes, 
  650 
  feet 
  

   above 
  O. 
  D. 
  in 
  Norfolk, 
  so 
  as 
  to 
  have 
  formed 
  cliffs 
  during 
  the 
  accumulation 
  

   of 
  the 
  Contorted 
  Drift 
  ; 
  for 
  I 
  do 
  not 
  think 
  that 
  the 
  elevation 
  to 
  which 
  the 
  

   beds 
  b 
  3 
  and 
  c 
  rise 
  to 
  form 
  Cromer 
  lighthouse 
  hill 
  (248 
  feet) 
  is 
  exceeded 
  by 
  any 
  

   point 
  in 
  Norfolk 
  to 
  the 
  extent 
  of 
  more 
  than 
  a 
  few 
  feet. 
  

  

  

  