﻿174 
  Bucher 
  — 
  Origin 
  of 
  Ripples, 
  and 
  

  

  water 
  with 
  more 
  sediment 
  to 
  settle 
  on 
  it, 
  the 
  core 
  wonld 
  

   be 
  completely 
  hidden 
  and 
  a 
  perfect 
  "dune" 
  formed. 
  

  

  3. 
  For 
  data 
  on 
  ivave-length 
  and 
  amplitude, 
  see 
  

   table 
  4. 
  

  

  2. 
  On 
  tidal 
  flats. 
  

  

  The 
  large 
  ripples 
  so 
  common 
  on 
  tidal 
  flats 
  were 
  

   described 
  in 
  a 
  very 
  elaborate 
  paper, 
  amply 
  supplied 
  with 
  

   excellent 
  photographs 
  by 
  Cornish, 
  25 
  from 
  which 
  the 
  

   following 
  data 
  were 
  taken. 
  

  

  1. 
  Ground 
  plan. 
  — 
  Where 
  well 
  developed, 
  the 
  pattern 
  

   exhibited 
  by 
  these 
  sand-waves 
  in 
  ground 
  plan 
  is 
  that 
  of 
  

   typical 
  current-ripples, 
  long, 
  more 
  or 
  less 
  sinuous 
  and 
  

   parallel 
  lines 
  of 
  ridges, 
  presenting 
  the 
  appearance 
  of 
  a 
  

   regular 
  train 
  of 
  waves, 
  despite 
  the 
  fact 
  that 
  the 
  succeed- 
  

   ing 
  individual 
  waves 
  show 
  an 
  average 
  difference 
  of 
  33-2 
  

   per 
  cent 
  of 
  the 
  mean 
  wave-length 
  (p. 
  174). 
  Cornish 
  

   points 
  out 
  that 
  "this 
  appearance 
  probably 
  depends 
  more 
  

   on 
  the 
  parallelism 
  of 
  the 
  ridges 
  than 
  upon 
  the 
  equality 
  

   of 
  their 
  wave-lengths, 
  especially 
  when 
  the 
  eye 
  elevation 
  

   is 
  small." 
  

  

  At 
  Montrose, 
  N. 
  B., 
  Cornish 
  observed 
  that 
  "with 
  a 
  

   strong 
  westerly 
  gale 
  blowing, 
  the 
  ridges 
  were 
  much 
  more 
  

   sinuous, 
  and 
  many 
  pools 
  of 
  water 
  remained 
  at 
  low 
  tide 
  

   owing 
  to 
  dams 
  across 
  troughs 
  where 
  sand 
  had 
  been 
  

   washed 
  in 
  from 
  the 
  ridges" 
  (p. 
  182). 
  

  

  In 
  general 
  also 
  "the 
  wave 
  fronts 
  of 
  the 
  ebb-facing 
  

   ridges 
  are 
  . 
  . 
  . 
  more 
  sinuous 
  than 
  those 
  of 
  the 
  flood; 
  

   they 
  suggest 
  formation 
  when 
  the 
  waters 
  are 
  running 
  

   together 
  as 
  the 
  banks 
  dry 
  out" 
  (p. 
  191). 
  

  

  The 
  trend 
  of 
  these 
  sand-waves 
  with 
  reference 
  to 
  the 
  

   shore 
  line 
  is 
  characteristic: 
  on 
  open 
  shores, 
  such 
  as 
  at 
  

   Mundsley 
  (p. 
  183), 
  or 
  above 
  the 
  mouth 
  of 
  Barmouth 
  

   estuary 
  (p. 
  174), 
  or 
  on 
  the 
  Goodwin 
  Sands 
  (p. 
  189), 
  six 
  

   miles 
  off 
  the 
  N-S 
  shore 
  of 
  Kent, 
  these 
  tidal 
  sand-waves 
  

   were 
  invariably 
  found 
  to 
  trend 
  at 
  right 
  angles 
  to 
  the 
  

   shore. 
  In 
  the 
  case 
  of 
  the 
  Goodwin 
  Sands 
  especially, 
  

   they 
  trend 
  in 
  the 
  direction 
  of 
  the 
  wind 
  and 
  at 
  right 
  angles 
  

   to 
  the 
  waves 
  "which 
  are 
  not 
  insignificant 
  on 
  the 
  Good- 
  

   wins 
  even 
  when 
  the 
  wind 
  is 
  light." 
  In 
  the 
  indentations 
  

   of 
  the 
  shore 
  line, 
  bays 
  and 
  estuaries, 
  of 
  course, 
  the 
  sand- 
  

   waves 
  trending 
  at 
  right 
  angles 
  to 
  the 
  shore 
  of 
  the 
  

   estuaries 
  may 
  run 
  parallel 
  with 
  the 
  general 
  shore 
  line. 
  

  

  25 
  1901; 
  good 
  illustrations 
  also 
  in 
  Kindle, 
  1917, 
  pi. 
  8. 
  

  

  