﻿96 
  J. 
  CLIFTON 
  WARD 
  ON 
  THE 
  ORIGIN 
  OF 
  SOME 
  

  

  14. 
  The 
  Origin 
  of 
  some 
  of 
  the 
  Lake-basins 
  of 
  Cumberland. 
  By 
  J. 
  

   Clifton 
  Ward, 
  Esq., 
  Assoc. 
  R.S.M., 
  E.G.S., 
  of 
  the 
  Geological 
  

   Survey 
  of 
  England 
  and 
  Wales. 
  (Read 
  January 
  7, 
  1874.) 
  

  

  [Plates 
  IX. 
  & 
  X.] 
  

  

  Eirst 
  Paper. 
  

  

  The 
  subject 
  of 
  the 
  origin 
  of 
  lake-basins 
  is 
  one 
  which 
  has 
  received 
  

   considerable 
  attention 
  at 
  the 
  hands 
  of 
  several 
  eminent 
  observers, 
  

   and 
  notably 
  of 
  Professor 
  Ramsay. 
  At 
  the 
  present 
  time 
  I 
  propose 
  

   to 
  discuss 
  the 
  origin 
  of 
  those 
  depressions 
  in 
  which 
  some 
  of 
  our 
  

   Cumberland 
  lakes 
  lie, 
  taking 
  as 
  examples 
  Derwentwater 
  and 
  Bas- 
  

   senthwaite, 
  and 
  Buttermere, 
  Crummock, 
  and 
  Loweswater. 
  The 
  two 
  

   former 
  lakes 
  I 
  have 
  myself 
  carefully 
  sounded 
  ; 
  the 
  latter 
  were 
  

   sounded 
  many 
  years 
  since 
  by 
  Mr. 
  P. 
  C. 
  Crosthwaite 
  ; 
  and 
  the 
  depths 
  

   obtained 
  by 
  him 
  will 
  here 
  be 
  made 
  use 
  of, 
  with 
  some 
  observations 
  of 
  

   my 
  own. 
  

  

  The 
  first 
  point 
  is 
  to 
  obtain 
  a 
  true 
  idea 
  of 
  the 
  proportions 
  and 
  

   depths 
  of 
  the 
  lakes 
  as 
  compared 
  with 
  the 
  surrounding 
  mountains. 
  

   For 
  this 
  purpose 
  I 
  have 
  drawn 
  a 
  number 
  of 
  sections 
  on 
  a 
  true 
  scale 
  

   (the 
  same 
  vertical 
  and 
  horizontal), 
  both 
  in 
  the 
  direction 
  of 
  the 
  

   length 
  of 
  the 
  lakes 
  and 
  transverse 
  to 
  that 
  direction. 
  In 
  the 
  case 
  

   of 
  the 
  longitudinal 
  sections 
  (figs. 
  1-3), 
  outlines 
  of 
  the 
  mountains 
  

   on 
  the 
  left 
  sides 
  of 
  the 
  respective 
  valleys 
  are 
  inserted, 
  with 
  their 
  

   true 
  height, 
  and 
  the 
  lakes 
  are 
  indicated 
  by 
  deep-black 
  lines 
  of 
  a 
  

   thickness 
  corresponding 
  to 
  the 
  various 
  depths. 
  To 
  form 
  a 
  strictly 
  

   accurate 
  idea 
  of 
  the 
  original 
  size 
  of 
  the 
  lakes, 
  the 
  following 
  points 
  

   must 
  also 
  be 
  taken 
  into 
  account. 
  Both 
  Derwentwater 
  and 
  Butter- 
  

   mere 
  must 
  formerly 
  have 
  extended 
  nearly 
  a 
  mile 
  higher 
  up 
  their 
  

   respective 
  valleys 
  (see 
  Map, 
  PI. 
  IX.). 
  Derwentwater 
  and 
  Bassen- 
  

   thwaite 
  were 
  once 
  continuous, 
  though 
  now 
  parted 
  by 
  some 
  three 
  

   miles 
  of 
  alluvial 
  land. 
  Buttermere 
  and 
  Crummock 
  were 
  likewise 
  

   originally 
  one, 
  though 
  three 
  quarters 
  of 
  a 
  mile 
  of 
  alluvium 
  now 
  

   separates 
  them. 
  The 
  filling 
  up 
  of 
  the 
  head 
  of 
  Derwentwater 
  is 
  due 
  

   to 
  the 
  matter 
  brought 
  down 
  by 
  the 
  river 
  Derwent 
  and 
  the 
  Watend- 
  

   lath 
  beck 
  ; 
  and 
  the 
  soundings 
  for 
  a 
  mile 
  and 
  a 
  quarter 
  north 
  of 
  the 
  

   mouth 
  of 
  the 
  Derwent 
  show 
  how 
  this 
  process 
  is 
  still 
  going 
  on, 
  the 
  

   depths 
  for 
  that 
  distance 
  only 
  increasing 
  from 
  5 
  to 
  18 
  feet, 
  there 
  

   being 
  much 
  deeper 
  channels 
  on 
  either 
  side 
  the 
  northern 
  part 
  of 
  this 
  

   shallow 
  tongue 
  (fig. 
  17). 
  The 
  Barrow 
  beck 
  has 
  also 
  done 
  its 
  share 
  

   of 
  work 
  in 
  forming 
  an 
  alluvial 
  fan 
  projecting 
  into 
  the 
  lake, 
  and 
  in 
  

   shallowing 
  the 
  parts 
  immediately 
  beyond. 
  The 
  tract 
  of 
  alluvium 
  

   between 
  Derwentwater 
  and 
  Bassenthwaite 
  has 
  been 
  formed 
  by 
  the 
  

   river 
  Greta 
  flowing 
  from 
  the 
  east, 
  and 
  the 
  Kewlands 
  beck 
  and 
  its 
  

   tributaries 
  flowing 
  from 
  the 
  south 
  and 
  west. 
  The 
  head 
  of 
  Butter- 
  

   mere 
  has 
  been 
  filled 
  up 
  by 
  the 
  detritus 
  borne 
  down 
  by 
  the 
  Gates- 
  

   garthdale 
  and 
  Warnscale 
  becks, 
  flowing 
  westwards 
  on 
  either 
  side 
  of 
  

  

  