﻿The 
  Age 
  of 
  the 
  Suffolk 
  Valleys. 
  379 
  

  

  The 
  paper 
  contains 
  a 
  large 
  number 
  of 
  chemical 
  analyses, 
  prin- 
  

   cipally 
  carried 
  out 
  by 
  the 
  chemists 
  of 
  the 
  Geological 
  Survey 
  of 
  

   Western 
  Australia. 
  By 
  the 
  kindness 
  of 
  the 
  Director 
  of 
  that 
  Survey 
  

   the 
  author 
  has 
  also 
  been 
  able 
  to 
  make 
  use 
  of 
  the 
  specimens 
  in 
  the 
  

   Survey 
  cabinets, 
  in 
  addition 
  to 
  those 
  collected 
  during 
  his 
  own 
  

   examination 
  of 
  the 
  goldfield. 
  

  

  May 
  28th.— 
  Dr. 
  Aubrey 
  Strata 
  n, 
  F.R.S., 
  President, 
  

   in 
  the 
  Chair. 
  

  

  The 
  following 
  communications 
  were 
  read 
  : 
  — 
  

  

  1. 
  'On 
  the 
  Age 
  of 
  the 
  Suffolk 
  Valleys 
  ; 
  with 
  Notes 
  on 
  the 
  Buried 
  

   Channels 
  of 
  Drift/ 
  By 
  Percy 
  G. 
  H. 
  Boswell, 
  B.Sc, 
  F.G.S. 
  

  

  The 
  main 
  watershed 
  of 
  Suffolk 
  follows 
  generally 
  the 
  Chalk 
  

   Escarpment, 
  but 
  keeps 
  rather 
  to 
  the 
  east 
  of 
  it, 
  running 
  in 
  a 
  north- 
  

   easterly 
  direction 
  from 
  Haverhill 
  in 
  the 
  extreme 
  south-west 
  of 
  the 
  

   county. 
  Suffolk 
  forms 
  a 
  plateau, 
  100 
  to 
  400 
  feet 
  O.D., 
  dissected 
  

   by 
  a 
  valley-system 
  which 
  is 
  palmate 
  in 
  form, 
  the 
  chief 
  rivers, 
  

   taken 
  from 
  north 
  to 
  south, 
  being 
  the 
  Waveney, 
  the 
  Aide, 
  the 
  

   Deben, 
  the 
  Gipping 
  (with 
  its 
  estuary, 
  the 
  Orwell), 
  the 
  Brett, 
  and 
  

   the 
  Stour. 
  The 
  Little 
  Ouse 
  and 
  the 
  Lark 
  flow 
  north-westwards 
  

   into 
  the 
  "Wash 
  basin. 
  

  

  The 
  strata 
  (Chalk, 
  Lower 
  London 
  Tertiaries, 
  London 
  Clay, 
  Crags, 
  

   etc.) 
  cut 
  through 
  by 
  the 
  valleys, 
  and 
  the 
  mantle 
  of 
  Glacial 
  deposits 
  

   (sands, 
  gravels, 
  and 
  loams, 
  Upper 
  Boulder 
  Clay, 
  and 
  morainic 
  

   gravels) 
  which 
  more 
  or 
  less 
  covers 
  the 
  whole 
  county, 
  are 
  described 
  

   briefly. 
  Reasons 
  are 
  given 
  for 
  thinking 
  that 
  the 
  Contorted 
  Drift 
  

   does 
  not 
  extend 
  far 
  south 
  of 
  the 
  Waveney. 
  The 
  valleys, 
  although 
  

   they 
  may 
  have 
  been 
  etched 
  earlier, 
  are 
  on 
  direct 
  evidence 
  post- 
  

   Pliocene 
  in 
  age 
  ; 
  but, 
  by 
  analogy 
  with 
  the 
  Waveney 
  and 
  the 
  

   Norfolk 
  rivers, 
  they 
  may 
  be 
  younger 
  than 
  the 
  Contorted 
  Drift. 
  

  

  The 
  Upper 
  Boulder 
  Clay 
  (=the 
  Great 
  Chalky 
  Boulder 
  Clay 
  of 
  

   S. 
  Y. 
  Wood, 
  Jr.) 
  covers 
  much 
  of 
  the 
  plateau, 
  and 
  wraps 
  down 
  

   into 
  the 
  valleys 
  in 
  a 
  very 
  characteristic 
  manner. 
  The 
  Glacial 
  

   Sands, 
  etc., 
  below 
  it 
  also 
  appear 
  at 
  times 
  to 
  lie 
  on 
  the 
  valley-slopes. 
  

   Intense 
  glacial 
  disturbances 
  are 
  found 
  to 
  be 
  situated 
  always 
  on 
  

   i 
  bluffs 
  ' 
  or 
  ' 
  spurs 
  ' 
  of 
  the 
  plateau 
  projecting 
  into 
  the 
  wide 
  open 
  

   valleys, 
  which 
  were 
  thus 
  in 
  existence 
  before 
  the 
  advent 
  of 
  the 
  

   valley-glaciers 
  to 
  the 
  action 
  of 
  which 
  the 
  disturbances 
  have 
  been 
  

   attributed. 
  

  

  In 
  each 
  of 
  the 
  main 
  valleys 
  occur 
  one 
  or 
  more 
  buried 
  channel 
  

   of 
  Drift 
  ; 
  borings 
  made 
  recently 
  allow 
  these 
  to 
  be 
  described 
  in 
  

   detail, 
  and 
  the 
  deposits 
  filling 
  them 
  to 
  be 
  discussed. 
  A 
  contour- 
  

   map 
  of 
  the 
  top 
  of 
  the 
  Chalk 
  is 
  prepared 
  for 
  the 
  county, 
  and 
  this 
  

   serves 
  to 
  bring 
  out 
  the 
  anomalies 
  in 
  the 
  valleys. 
  These 
  buried 
  

   channels 
  were 
  probably 
  eroded 
  by 
  sub-glacial 
  water-streams, 
  and 
  a 
  

   comparison 
  is 
  instituted 
  between 
  them 
  and 
  the 
  Pohrden 
  of 
  North 
  

   Germany, 
  Schleswig-Holstein, 
  Kerguelen, 
  etc., 
  described 
  in 
  detail 
  

   by 
  Dr. 
  Werth 
  and 
  others. 
  

  

  The 
  evidence, 
  therefore, 
  indicates 
  that 
  the 
  pre-Glacial 
  or 
  early 
  

   Glacial 
  contours 
  of 
  Suffolk 
  were 
  in 
  the 
  main 
  much 
  as 
  they 
  are 
  now. 
  

  

  