﻿256 
  Bucher 
  — 
  Origin 
  of 
  Ripples, 
  and 
  

  

  at 
  times 
  with 
  a 
  velocity 
  of 
  0-215 
  m. 
  p. 
  sec. 
  at 
  a 
  depth 
  of 
  

   250 
  m. 
  The 
  lowest 
  velocity 
  observed 
  was 
  0-059 
  m.p. 
  sec. 
  

   "This 
  velocity 
  is 
  so 
  great 
  that 
  the 
  water 
  would 
  move 
  

   grains 
  of 
  sand, 
  and 
  wash 
  them 
  away 
  from 
  the 
  bottom, 
  

   which 
  at 
  this 
  place 
  was 
  rocky. 
  ' 
  ' 
  40 
  

  

  From 
  ripples 
  found 
  in 
  marine 
  sediments, 
  therefore, 
  

   no 
  other 
  reliable 
  information 
  can 
  be 
  obtained 
  than 
  that 
  

   there 
  existed 
  currents 
  of 
  some 
  kind 
  which 
  touched 
  the 
  

   bottom. 
  Since 
  the 
  conditions 
  of 
  preservation 
  are 
  the 
  

   same 
  for 
  both 
  current 
  and 
  oscillation-ripples, 
  the 
  absence 
  

   of 
  one 
  or 
  the 
  other 
  type 
  in 
  a 
  sediment 
  must 
  be 
  accounted 
  

   for 
  in 
  other 
  ways. 
  The 
  Bedford-Berea 
  ripples 
  offered 
  

   an 
  excellent 
  example 
  for 
  the 
  one 
  case. 
  In 
  the 
  limestone- 
  

   shale 
  series 
  of 
  the 
  Eden 
  and 
  Richmond 
  Groups 
  of 
  the 
  

   Cincinnati 
  Anticline 
  current-ripples 
  are 
  common, 
  while 
  

   I 
  have 
  so 
  far 
  not 
  seen 
  a 
  single 
  case 
  of 
  undoubted 
  oscilla- 
  

   tion-ripples. 
  While 
  I 
  have 
  no 
  doubt 
  that 
  they 
  will 
  be 
  

   found, 
  their 
  scarcity 
  is 
  certainly 
  significant 
  and 
  a 
  good 
  

   evidence 
  of 
  the 
  rather 
  constant 
  current 
  action 
  in 
  these 
  

   seas, 
  which 
  were 
  shown 
  to 
  have 
  been 
  largely 
  tidal. 
  

  

  3. 
  Fluviatile 
  current-ripples. 
  — 
  While 
  in 
  marine 
  sedi- 
  

   ments 
  the 
  trend 
  of 
  ripples 
  seems 
  of 
  little 
  value 
  to 
  the 
  

   paleogeographer, 
  its 
  study 
  may 
  yield 
  important 
  results 
  

   in 
  fluviatile 
  deposits, 
  the 
  true 
  nature 
  and 
  wide 
  distribu- 
  

   tion 
  of 
  which 
  among 
  the 
  sediments 
  of 
  the 
  past 
  we 
  are 
  

   just 
  beginning 
  to 
  realize. 
  There 
  are 
  no 
  sediments 
  in 
  

   which 
  ripples 
  of 
  any 
  kind 
  are 
  of 
  more 
  common 
  occurrence 
  

   and 
  find 
  better 
  chances 
  of 
  preservation 
  than 
  the 
  sands 
  

   and 
  muds 
  of 
  alluvial 
  plains. 
  41 
  

  

  In 
  the 
  deposits 
  of 
  a 
  river 
  obviously 
  a 
  great 
  majority 
  of 
  

   all 
  ripples 
  should 
  be 
  found 
  facing 
  approximately 
  in 
  the 
  

   direction 
  of 
  flow 
  of 
  the 
  river. 
  Locally, 
  of 
  course, 
  they 
  

   can 
  be 
  found 
  facing 
  even 
  in 
  an 
  opposite 
  direction, 
  as 
  along 
  

   parts 
  of 
  meanders 
  or 
  under 
  the 
  influence 
  of 
  local 
  eddies. 
  

   Such 
  cases 
  can 
  not, 
  however, 
  seriously 
  affect 
  the 
  average 
  

   direction 
  obtained 
  from 
  numerous 
  determinations. 
  

  

  This 
  is 
  also 
  true 
  of 
  the 
  ripples 
  on 
  compound 
  alluvial 
  

   fans. 
  An 
  analysis 
  of 
  the 
  ripples 
  in 
  sediments 
  which 
  are 
  

   interpreted 
  as 
  alluvial 
  fillings 
  of 
  rift 
  valleys, 
  as, 
  for 
  

   instance, 
  the 
  Newark 
  series 
  in 
  Connecticut, 
  42 
  should 
  prove 
  

   especially 
  interesting. 
  

  

  Holland 
  Hansen 
  and 
  Nansen, 
  loc. 
  cit., 
  p. 
  155; 
  ef. 
  also 
  table 
  1 
  of 
  Part 
  I 
  

   of 
  this 
  paper. 
  

  

  "Of. 
  also 
  p. 
  269 
  (Part 
  II). 
  

  

  42 
  J. 
  Barrell, 
  Central 
  Connecticut 
  in 
  the 
  Geologic 
  Past, 
  Proc. 
  and 
  Coll. 
  

   of 
  the 
  Wyoming 
  Hist, 
  and 
  Geol. 
  Soc, 
  vol. 
  12, 
  pp. 
  1-30, 
  1911. 
  

  

  