﻿686 
  SEAELES 
  V. 
  WOOD 
  OK 
  THE 
  NEWEK 
  

  

  of 
  the 
  Pennine 
  is, 
  that 
  throughout 
  the 
  major 
  glaciation 
  the 
  ice 
  filled 
  

   all 
  the 
  lower 
  ground 
  between 
  the 
  Pennine 
  and 
  the 
  Wold, 
  in 
  conse- 
  

   quence 
  both 
  of 
  the 
  less 
  depression 
  of 
  this 
  side 
  during 
  the 
  submergence, 
  

   and 
  of 
  its 
  having 
  been 
  that 
  originally 
  filled 
  by 
  the 
  ice 
  in 
  its 
  passage 
  

   to 
  the 
  sea 
  at 
  the 
  outset 
  of 
  the 
  glaciation, 
  when 
  the 
  sea 
  was 
  confined 
  to 
  

   the 
  eastern 
  side 
  of 
  England 
  : 
  so 
  that 
  throughout 
  the 
  glaciation 
  it 
  kept 
  

   out 
  the 
  sea 
  until 
  this 
  part 
  had 
  emerged, 
  the 
  ice 
  continuing 
  in 
  this 
  

   part 
  after 
  it 
  had 
  retired 
  altogether 
  from 
  East 
  Anglia. 
  Thus, 
  instead 
  

   of 
  the 
  gravels 
  6' 
  and 
  c 
  having, 
  as 
  suggested 
  in 
  the 
  first 
  part 
  of 
  this 
  

   memoir, 
  been 
  destroyed 
  over 
  the 
  space 
  between 
  the 
  Pennine 
  and 
  the 
  

   broken 
  line 
  on 
  Map 
  1, 
  by 
  the 
  advance 
  of 
  the 
  ice 
  which 
  formed 
  the 
  

   Chalky 
  Clay, 
  they 
  never 
  existed 
  over 
  so 
  much 
  of 
  that 
  space 
  as 
  is 
  

   represented 
  in 
  Map 
  4 
  as 
  occupied 
  by 
  ice. 
  

  

  The 
  intermittent 
  beds 
  of 
  sand 
  marked 
  c 
  in 
  fig. 
  XL 
  VI. 
  seem 
  to 
  have 
  

   been 
  deposited 
  after 
  the 
  Mollusca, 
  which 
  established 
  themselves 
  on 
  

   the 
  moraine 
  of 
  Easement 
  Clay 
  (B) 
  as 
  the 
  ice 
  of 
  this 
  retreated, 
  had 
  

   ceased 
  to 
  live 
  there, 
  no 
  trace 
  of 
  shells 
  having 
  yet 
  been 
  detected 
  in 
  

   these 
  beds. 
  Their 
  accumulation 
  appears 
  to 
  have 
  accompanied 
  the 
  

   inroad 
  of 
  the 
  ice 
  of 
  the 
  Purple 
  Clay 
  (D), 
  for 
  they 
  are 
  mixed 
  up 
  with 
  

   sheet-like 
  fragments 
  of 
  both 
  the 
  Basement 
  and 
  Purple 
  Clays, 
  and 
  are 
  

   only 
  occasionally 
  present. 
  

  

  There 
  are 
  four 
  particular 
  sources 
  from 
  which 
  erratic 
  blocks 
  have 
  

   been 
  traced, 
  viz. 
  : 
  — 
  Criffel, 
  near 
  the 
  Scotch 
  shore 
  of 
  the 
  Solway 
  Firth 
  ; 
  

   Eskdale, 
  near 
  Ravenglass 
  on 
  the 
  Cumberland 
  coast 
  ; 
  Shap, 
  in 
  West- 
  

   moreland 
  ; 
  and 
  Arenig, 
  in 
  North 
  Wales. 
  These 
  places 
  are 
  shown 
  on 
  

   Map 
  4 
  with 
  lines 
  indicating 
  the 
  routes 
  which 
  the 
  blocks 
  from 
  them 
  

   have 
  taken, 
  and 
  the 
  limits 
  to 
  which, 
  as 
  far 
  as 
  known, 
  they 
  have 
  reached. 
  

   Now 
  Mr. 
  Mackintosh 
  (from 
  whose 
  papers* 
  the 
  line3 
  followed 
  by 
  these 
  

   blocks, 
  save 
  part 
  of 
  the 
  line 
  followed 
  by 
  the 
  Shap, 
  are 
  taken) 
  states 
  

   that 
  the 
  blocks 
  and 
  fragments 
  from 
  Criffel, 
  Pavenglass, 
  and 
  Arenig 
  

   are 
  all 
  distributed 
  over 
  the 
  area 
  occupied 
  by 
  the 
  tint 
  of 
  ruled 
  lines 
  in 
  

   Sheets 
  72, 
  73, 
  74, 
  79, 
  80, 
  89, 
  and 
  90 
  (most 
  of 
  which 
  is 
  of 
  no 
  great 
  

   elevation) 
  ; 
  but 
  that 
  none 
  of 
  them, 
  save 
  those 
  from 
  Arenig, 
  occur 
  

   west 
  of 
  a 
  line 
  corresponding 
  to 
  that 
  which 
  I 
  have 
  represented 
  as 
  the 
  

   eastern 
  boundary 
  of 
  the 
  Welsh 
  ice. 
  The 
  Arenig 
  blocks, 
  on 
  the 
  con- 
  

   trary, 
  he 
  says 
  are 
  distributed 
  within 
  the 
  part 
  representing 
  the 
  Welsh 
  

   ice 
  up 
  to 
  elevations 
  exceeding 
  2000 
  feet, 
  to 
  which 
  height 
  he 
  in 
  con- 
  

   sequence 
  regards 
  the 
  submergence 
  as 
  reaching. 
  Mr. 
  Mackintosh 
  

   attributes 
  the 
  arrest 
  of 
  the 
  Criffel 
  and 
  Eavenglass 
  blocks 
  at 
  this 
  line 
  

   to 
  a 
  conflict 
  of 
  currents 
  ; 
  but 
  it 
  appears 
  to 
  me 
  to 
  be 
  susceptible 
  of 
  

   the 
  more 
  simple 
  explanation 
  that 
  I 
  suggested 
  to 
  him, 
  and 
  which 
  he 
  

   notices 
  in 
  his 
  paperf 
  , 
  but 
  which, 
  as 
  it 
  is 
  part 
  of 
  the 
  case 
  presented 
  

   by 
  this 
  memoir, 
  I 
  now 
  advert 
  to. 
  

  

  If 
  we 
  regard 
  the 
  Arenig 
  blocks 
  and 
  fragments 
  as 
  having 
  been 
  

  

  * 
  Quart. 
  Journ. 
  Greol. 
  Soc. 
  vol. 
  xxix. 
  p. 
  351, 
  vol. 
  xxx. 
  p. 
  721, 
  & 
  vol. 
  xxxvii. 
  

   p. 
  361. 
  

  

  t 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxxvii. 
  p. 
  361, 
  footnote. 
  Mr. 
  Mackintosh 
  

   objects 
  to 
  this 
  view 
  on 
  the 
  ground 
  that, 
  the 
  land-ice 
  from 
  Arenig 
  could 
  not 
  

   have 
  attained 
  a 
  surface-level 
  of 
  1500 
  feet 
  above 
  the 
  present 
  sea 
  by 
  the 
  time 
  

   it 
  reached 
  the 
  line 
  where 
  I 
  regard 
  it 
  as 
  terminating 
  in 
  the 
  sea. 
  As, 
  how- 
  

  

  