﻿2#8 
  Bucher 
  — 
  Origin 
  of 
  Ripples, 
  and 
  

  

  I, 
  have 
  always, 
  as 
  far 
  as 
  I 
  know, 
  been 
  found 
  where 
  the 
  

   depth 
  of 
  running 
  water 
  was 
  rapidly 
  diminished 
  to 
  com- 
  

   plete 
  exposure. 
  They 
  are 
  equally 
  common 
  on 
  tidal 
  flats 
  

   as 
  on 
  floodplains 
  and 
  therefore 
  can 
  be 
  considered 
  as 
  indi- 
  

   cators 
  of 
  this 
  special 
  condition. 
  During 
  the 
  G. 
  S. 
  A. 
  

   meeting 
  at 
  Albany, 
  New 
  York, 
  there 
  were 
  exhibited 
  

   excellent 
  specimens 
  of 
  negatives 
  of 
  this 
  type, 
  if 
  I 
  remem- 
  

   ber 
  correctly, 
  from 
  the 
  Portage 
  Sandstone 
  of 
  New 
  York, 
  

   together 
  with 
  plaster 
  casts 
  showing 
  their 
  true 
  form. 
  

   Cox 
  and 
  Dake 
  figure 
  a 
  good 
  specimen 
  from 
  the 
  Roubidoux 
  

   sandstone 
  of 
  the 
  vicinity 
  of 
  Rolla, 
  Missouri, 
  45 
  and 
  Kindle 
  

   one 
  from 
  the 
  Carboniferous 
  Sandstone, 
  Joggins 
  section, 
  

   N. 
  S. 
  4G 
  Kindle 
  also 
  called 
  attention 
  to 
  the 
  fact 
  that 
  the 
  

   laminations 
  of 
  such 
  linguoid 
  ripples, 
  when 
  exposed 
  by 
  

   erosion, 
  resemble 
  the 
  problematic 
  burrows, 
  described 
  as 
  

   Taonurus. 
  Surfaces 
  like 
  the 
  one 
  figured 
  by 
  him 
  on 
  plate 
  

   31 
  are 
  commonly 
  met 
  with, 
  for 
  instance, 
  in 
  the 
  rocks 
  of 
  

   the 
  Pottsville 
  group 
  of 
  Kentucky. 
  

  

  The 
  evidence 
  offered 
  by 
  these 
  linguoid 
  ripples 
  is 
  defi- 
  

   nite 
  and 
  should 
  be 
  used 
  in 
  combination 
  with 
  other 
  data, 
  

   giving 
  clues 
  to 
  the 
  marine 
  or 
  terrestrial 
  nature 
  of 
  the 
  

   sediments. 
  

  

  In 
  marine 
  deposits 
  they 
  should 
  be 
  confined 
  to 
  a 
  narrow 
  

   zone, 
  corresponding 
  to 
  the 
  tidal 
  fiats 
  ; 
  or 
  they 
  might 
  be 
  

   found 
  over 
  a 
  wide 
  area 
  in 
  a 
  formation 
  of 
  limited 
  thick- 
  

   ness 
  ascending 
  obliquely 
  through 
  the 
  stratigraphic 
  

   column 
  due 
  to 
  progressive 
  marine 
  overlap 
  pushing 
  the 
  

   marginal 
  zone 
  forward 
  across 
  the 
  land. 
  

  

  If 
  they 
  are, 
  however, 
  found 
  throughout 
  a 
  considerable 
  

   thickness 
  of 
  a 
  formation 
  of 
  fixed 
  position 
  in 
  the 
  strati- 
  

   graphic 
  column, 
  covering 
  a 
  wide 
  area, 
  they 
  offer 
  a 
  strong 
  

   argument 
  in 
  favor 
  of 
  a 
  terrestrial, 
  fhrviatile 
  origin. 
  

  

  III. 
  Large 
  Current-ripples. 
  

  

  1. 
  Description. 
  

  

  Large 
  current-ripples 
  were 
  described 
  or 
  mentioned 
  

   from 
  the 
  lower 
  Ordovician 
  dolomites 
  of 
  Illinois 
  47 
  and 
  

   Prom 
  the 
  Trenton 
  at 
  a 
  number 
  of 
  localities 
  in 
  New 
  York 
  

  

  46 
  Cox, 
  Gr. 
  II., 
  and 
  Dake, 
  C. 
  L., 
  Geologic 
  criteria 
  for 
  determining 
  the 
  struc- 
  

   tural 
  position 
  of 
  sedimentary 
  beds, 
  Bull. 
  School 
  of 
  Mines, 
  Univ. 
  of 
  

   Missouri, 
  vol. 
  2, 
  No. 
  4, 
  pi. 
  IIB, 
  1916. 
  

  

  1 
  B. 
  .\F. 
  Kindle, 
  Recent 
  and 
  Fossil 
  Bipple-Marks, 
  Geol. 
  Survey, 
  Canada, 
  

   Museum 
  Bull. 
  25, 
  p. 
  121, 
  1917. 
  

  

  "Udden, 
  J. 
  A., 
  Jon,-. 
  Geol., 
  vol. 
  24, 
  p. 
  125, 
  1916. 
  

  

  